This section contains information that augments the information in the Bentley Service Manual.
All information contained in this FAQ is provided by BMW enthusiasts who are not typically fully trained in the art of BMW maintenance. As such, all information in this FAQ is provided "as-is". Any use of this information is strictly the responsibility of the using party. The supplier of the information and the Webmeister assume no liability for incorrect information or use of this information.
Transmission Seals - Check First
Replacing the Transmission Seals
Article on Redline MTL for Transmissions
Gearshift Carrier Repair
Clutch Master Cylinder Removal/Installation
Complete Driveline Refurbishment
Transmission Swap Getrag 260 to 265
Transmission Seals - Check First - Steve Morey <email@example.com>
I installed two output seals and a selector shaft seal in my M6 before finding the real source of the leak. I suggest before you do anything you should *thoroughly* clean & de-grease the tranny, Guibo, and surrounding area. Go for a drive on the freeway at high speeds, put the car back up on stands and with a light, carefully inspect. If there is fluid on the front of the Guibo disc then your output seal and perhaps the selector shaft seal are the culprit (you might as well replace both because the R&R is the same). If the front of the Guibo is dry then you most likely are leaking way up on the top, rear of the tranny. This is the only other place that even has an opening in the case. To save some time, here is a copy of an old post I made to the BMW Digest:
I had a similar problem on my M6, turned out not to be the output seal. In my case I first thoroughly pressure cleaned everything to trace the leak. After 2 output seals and a selector shaft seal (I assume you are talking about a 5-speed) the leak persisted. I noticed, however, that there was no fluid on the front of the Guibo disc where you would expect it. It turned out that the small detent spring cover plate on the top rear of the transmission was the culprit. This should be set in a sealant like Permatex per the manual. In my case, not only was the sealant gone, the plate was *very* warped. After milling it flat and re-installing in sealant, no problems! (and no more smell from fluid on the cat).
Look to see if the front of your Guibo is wet. If it is, you probably have some damage to the seating surface of your output seal (or the selector shaft seal is shot).
While you are under there, reach up on the top front (driver's side near bellhousing) and make sure that the vent is not clogged. If it is it will force too much pressure against your new seals at high speed.<
If anyone does indeed have a leak from the detent-spring cover plate, I can provide more details on the cure.
Replacing the Transmission Seals - Andre Grandi <firstname.lastname@example.org>
The procedure below was done on an 1983 U.S. 633csi with a Getrag 260-5 speed transmission. The procedure should be similar on other E-24's if not identical. I would strongly suggest that you read Steve Morey's FAQ report on troubleshooting a leaky transmission before you do this procedure.
I noticed the guibo was wet in the front so I took a peak under there and found the culprit. The selector rod seal was toast. Since I was in there I decided to change the output shaft seal, and the transmission cross-member bushings. The shifter pillow block bushings needed to be changed along with the rear rubber shift bracket bushing.
30mm thinwall deep socket
19mm socket and wrench
13mm socket and wrench
2 medium flat blade screwdrivers
8mm hex socket
Pneumatic impact ratchet
Hydraulic floor jack
Snap ring pliers
Safety stands and glasses
1 small flat blade screwdriver
1 selector rod seal
1 transmission output seal
2 pillow block bushings
1 crush lock washer
2 transmission cross-member bushings(green color for heavy duty use)
1 rear shifter bracket bushing
242 loctite(BLUE liquid--stay away from the red stuff!)
Jack all four wheels of the car up as high as possible. Leave the emergency brake off and the transmission in neutral. Loosen the muffler from the rear bracket and the center support hangers. Make sure the muffler is resting on something, and don't leave it hanging from the exhaust manifold.
My car has a 1 piece steel exhaust pipe with a muffler at the end. I just loosened the rear muffler bracket and the two exhaust hangers forward of the differential. On cars with the resonator/cat I think you can get by with just removing the rear exhaust attachment points. The exhaust will rub on the right front thrust arm attaching bracket so it is a good idea to support the rear of the exhaust with something.
Remove the 10mm nuts on the center driveshaft bearing heat shield. > Loosen the two 13mm nuts on the center driveshaft bearing. Using the 19mm air ratchet and a 19mm wrench, remove the three bolts holding driveshaft to the guibo. Now the driveshaft should slide off the guibo. Make sure the center bearing drops down to the floor. The driveshaft should still be attached at the differential. Slide the driveshaft to the side.
Remove the three remaining bolts on the guibo from the transmission output flange. Next take a small flat blade screw driver and remove the crush lock washer from the transmission output flange. Take your 30mm socket and an air ratchet and remove the output flange nut. Pull the output flange off. You may need a gear puller for this, mine just slid off. Disconnect the two clips holding the shifter linkage and remove the transmission shifter rod. Make sure you can see the naked selector rod at this point.
The transmission does not need to be lowered to change the shifter bushings. However it can simplify your job a little. You should lower the transmission to get to the selector rod seal. Support the rear of the transmission with a floor jack and loosen the 2 transmission crossmember nuts with a 13mm socket. Lower the transmission as much as possible. The transmission drops about 3-4 inches.
If you need to change the transmission shifter bushings then read on. Remove the 13mm nut holding the rear shifter bracket. Remove the two hex pillow block hex bolts with the 8mm socket. The metal shifter bracket should drop down. Using the 10mm wrench and socket remove the two bolts. Reinstall the pillow block bushings. Take your pliers and remove the rear shifter bracket bushing. Insert the new bushing by pulling the end through both brackets. Leave the shifter bracket off until the selector seal has been replaced.
Using two flat blades try and jerk the output shaft seal out. Mine would not budge even with the small grooves cut in the screwdrivers for grabbing the seal. I took my flat blade screwdriver and pushed the bottom of the seal into the transmission causing the top of the seal to pop out. Take your pliers and remove the seal. Look at the seal seating surface in the transmission and verify that any remaining seal material has been removed. Use a clean rag with some mineral spirits or your cleaner of choice to clean the surface.
To install the new seal use a large socket(1"5/8) that covers just inside the inner circumference of the seal. Lightly tap the seal into place. Make sure the seal does not go in crooked. If necessary remove the socket and lightly tap the sides until the seal is flush with the transmission housing.
Next, take a screwdriver and tap the bottom of the selector seal into the transmission. The seal will not fall in because of a lip inside the transmission, but it will deform enough so the top of the seal pops out. Take a small flat blade and pry the top of the seal out. To reinstall the new seal find a deepwell socket and gently tap the seal into place. Make sure the seal is fully seated against the inner lip on the inside of the transmission.
Reinstall the transmission shifter bracket and the two hex bolts into the transmission. Use loctite on the hex bolts. Reinstall the shifter linkage and tighten the rear bracket bushing with a 13mm wrench. Shifter linkage should be completely installed at this point. Verify that everything is moving properly.
If you are replacing the transmission cross-member bushing read on. Using a floor jack support the rear of the transmission and remove the two bolts that hold the exhaust bracket to the transmission with a 13mm socket. Swing the bracket out of the way. Loosen the two top bushing bolts with a 13mm wrench. Loosen the two cross-member nuts with a 13mm socket and slide the cross-member off of the car. Remove the bushings with a 10mm socket.
Reinstall the cross-member and tighten both top and bottom bolts on the cross-member. Reinstall the exhaust bracket hanger and remove the floor jack.
Reinstall the transmission output flange, lightly tap to make sure it is fully seated on the shaft. With the 30mm socket reinstall the nut, make sure it is tight. Add a thin bead of blue loctite to the face of the 30mm nut. The idea is to seal the threads on the output shaft to the face of the 30mm nut. It is a good idea to do this to prevent possible transmission oil seepage. Oil can travel down the splined output shaft and around the threaded end of the shaft. Adding loctite should keep the oil from escaping.
Install the crush washer and notch the three ends locking the washer inside the flange. Install the guibo to the output flange with the three bolts. Torque these bolts down to factory specs. Install the driveshaft into the guibo and reconnect the driveshaft center support bearing. Bolt the remaining three bolts from the driveshaft to the guibo.. Reinstall the heat shield and reconnect the exhaust.
Total time should be around 3 hours if everything goes well. Air tools really speed up the process with this type of work. Lower the car and go for a spin!
Article on Redline MTL for Transmissions
In your BMW transmission, I would recommend the Red Line MTL, this is a GL-4 gear lube as is called for. The sulphur content of a gear lube is a factor of the type additive package used in the fluid and separate from the base stock either synthetic or petroleum. Synthetic oils are not corrosive by nature. The extreme pressure chemistry used in many gear oils can be corrosive to brass and bronze used in synchronizers and bushings. Most gear oils are corrosive at temperatures of 200°F. The MTL is not corrosive at temperatures over 375°F. A corrosive gear oil can shorten synchronizer life by half and can also contribute to rust problems. The transmission builders have not used the MTL or Red Line gear oils, as they are not corrosive. The MTL will work will in your transmission offering very good shiftability and protection.
I am attaching two PDF files one on our gear lubes and one on the MTL. Thank you for your interest in Red Line Oil.
Gearshift Carrier Repair - "sean barry" <email@example.com>
Better than new fix.
What you need:
1- #3 or #3.5 black rubber stopper, the kind used to stopper chemical bottles.
1- 50x8mm stud
2- 8mm nuts
2- 8mm washers
Total cost less than $5.00
-Drill a hole, 7mm, through the center of the stopper if it doesn't already have one. They come both ways, but most labratory supply places should have them with holes already. The one I used already had a hole and the stud fit perfectly.
-The stopper will be conical and it's hard to get it in like this so I milled mine to a cylinder using the hole as the axis.
-Press the stud evenly through the stopper, suddenly looks like a mount doesn't it.
-Using the nuts and washers remount the rear of your carrier, a crows foot really helps here.
-Enjoy much improved driving.
Sean Barry 84 633CSi
Clutch Master Cylinder Removal/Installation - "Gene M." <firstname.lastname@example.org>
Changing the clutch master cylinder is not an easy job, but it is something a DIYer can do with the proper tools. Most books will recommend that you also change the clutch slave cylinder at the same time (not covered in this). Before tackling this job, be sure your problem isn't just the need to bleed the clutch hydraulic system and that you really do need to replace the master cylinder. Also remember that the clutch hydraulic system uses brake fluid so protect your carpets and paint and your eyes.
Removal--Under the Hood
Use a turkey baster or equivalent to draw out the brake/clutch fluid from the reservoir until the level is below the fitting on the side of the reservoir that feeds the clutch hydraulic system. I would suggest you change the rubber hose coming off of the reservoir that feeds the clutch hydraulics, so at this point I would remove this hose from the reservoir. (Use the proper replacement, which is currently blue with a fabric mesh sheath on the outside--brake fluid eats up a lot of things and you don't want it to eat up this hose and have to remove the master cylinder again.)
At the tip of the clutch master cylinder there is an 11mm flare nut fitting. Access to this fitting is tough. If you jack up the car you can see it from underneath but the steering and suspension components block your arm from getting a flare nut wrench on it. You need to go in from the top and work in the blind. You should be able to get your left arm down in between the engine and the brake booster and reach around and get to this 11mm flare nut. Expect it to be very tight. Do not try to loosen it with anything other than a good flare nut wrench. Rounding off flare nut fittings on these cars can get expensive because they use a "bubble flare". At this point, use a rag to clean the fitting and loosen this flare fitting (you can remove it and cover the end with a plastic bag and a tie if you are sure you can complete the Under the Dash section).
Removal--Under the Dash.
You first need to remove the kick panel under the steering wheel. It usually has a couple of phillips screws under edge of the dash, one on each side of the steering wheel. There are a couple of other screws (phillips or hex head) a little farther forward toward the edges of the kick panel (around the hood release on one side and in the same area on the other side). Make sure you disconnect the wiring connectors for the seat belt/door chime, and the wire connector and the rubber hose fitting to the climate control sensor. Remove the kick panel out of the area and move the seat all the way back to get enough room to maneuver to get at the clutch master cylinder.
Before disconnecting the master under the dash, I recommend that you disconnect the 11mm flare nut fitting on the end in the engine compartment (see under the hood) because that flare fitting will be on tight and you may not be able to remove it if the master cylinder is flopping around on the inside.
Two 10mm bolts hold the clutch master in place up on a bracket in front and above the clutch pedal. Look up high and by the firewall--they are hard to see and hard to get a socket on them. You need to depress the gas pedal to move that linkage out of the way to get at these bolts from the left side (the nuts on the right side are welded in place). You will need to use a 1/4" drive, 10mm socket with a short extension (75mm) and a hinged handle to get at the front bolt (closest to firewall). The rubber "stop" for the clutch pedal mounted on the firewall restricts access. You can use a ratchet handle on the rear bolt. I don't think there is any way you can get at these bolts with a wrench or 3/8" drive socket. These bolts will be on tight so make sure your socket is fully on these bolts so you do not round off the edges.
The end of the master clutch cylinder that attaches to the clutch pedal is held by a bolt. 13mm and 17mm wrenches are needed to remove the bolt Make a note of which direction the bolt goes in from and which side the master cylinder is mounted to the pedal.
If the under the hood flare nut fitting and the rubber feed line on the fluid reservoir were removed, the clutch master can now be pulled out. (If you are not planning on replacing the rubber feed line, you may want to remove the plastic fitting on top of the master cylinder but I think you will find that it isn't easy to do this working in the cramped area). You may need to loosen (not remove) the bracket that holds the switch in to disengage the cruise control for the clutch pedal so that it can be swung out of the way to get room to slide out the master cylinder. A 10mm open end wrench is needed and the nut to loosen is on the brake pedal side. Be sure to have rags down on the floor to catch any fluid that drips (brake fluid bleaches out carpets and corrodes metal).
I would recommend that you get a new plastic fitting for the top of the master cylinder and have it around even if you are not replacing the feed hose in case the old one breaks.
Installation--Under the Dash
I don't know if it is needed, but I "prime" the new master cylinder by putting some brake fluid into the feed side to get some lubrication on the seals. Put on the new plastic fitting and attach the feed line--put a plug in the other end of the feed line so that you don't get debris when running it through the firewall. Loosen the end plug so that when you are working back under the hood you can easily get it off but leave it on so that you don't get debris when running it through the firewall.
Loosely rebolt the master cylinder in place. Make sure the end is on the correct side of the pedal before you start threading in those 10mm bolts and make sure you are not cross-threading them. I tend to use a bit of non-hardening grease on the large bolt that attaches to the pedal to make sure the plunger can freely move on the bolt. Don't tighten everything all the way because a little "play" may help reconnect that 11mm flare nut fitting under the hood.
Installation--Under the Hood
At this point I reconnect the 11 mm flare nut fitting on the end of the master cylinder. This can be very difficult working with the left hand in the "blind" because the hard pipe may not give you the proper angle to get the threads started. If you are not straight on, you won't be able to get this back on and will rub your fingertips off. I have recently started to disconnect the 11mm flare fitting that is at the bottom of the metal pipe going down to the clutch slave cylinder to make the other connection at the end of the master cylinder less frustrating. This involves jacking up the car to get at this lower fitting (again make sure to thoroughly clean the area before opening hydraulic lines and keep your face away because you will get fluid dripping when you disconnect), lowering the car and attaching at the master cylinder, jacking back up and reattaching the lower fitting.
Reattach the feed line to the reservoir making sure your line is not kinked both under the dash and under the hood. If your car didn't use one, you may want to use a hose clamp or zip tie to hold this feed line in place--especially if you pressure bleed your clutch or brake lines.
Installation--Back under the Dash
Now tighten up the 10 mm and the 13mm/17mm bolts. After you have replaced the clutch slave cylinder (if applicable) and have refilled and bled the hydraulic system and you know the clutch is working, double check for leaks under the dash before reinstalling the kick panel. Remember to reconnect the wire connector and rubber hose to the climate control sensor.
Complete Driveline Refurbishment - Sean Barry <email@example.com>
The following describes the complete refurbishment, except rebuilding the
transmission, on a 1984 633CSi, other e24's and e28's should be similar.
Rear main seal
Rear seal housing gasket
Pilot bearing cap
8 Flywheel to crank bolts
6 pressure plate to flywheel bolts
Throw out bearing
Transmission input shaft seal
Selector shaft seal
Transmission output shaft seal
Selector console mounts, front and rear
Center support bearing
2 Differential output seals
2 Differential output snap rings
2 rebuilt half-shafts
Transmission and differential oil
PBlaster/WD40 or some such spray oil
Exhaust manifold to pipes gaskets
6 Copper nuts exhaust to pipes
front exhaust hangers
rear exhaust hanger
12 of your favorite malted beverage
30mm thin-walled deep-socket
Pilot bearing puller
Torque wrench, a real one. Not a bar with a pointer that deflects.
Wobbly extensions, several
Clutch alignment tool
Floor or transmission jack
4 Jack stands
A good assortment of hand tools
OK, I’ve decided to do this job, actually my car decided for me. Having good light makes this job tons easier. Basically this is what I decided to do since so much of this has to be done to do any of these things individually it just made sense to get it all out of the way at one time. Please email me with any corrections.
First disconnect the battery, jack the car up, setting the stands as high as possible at all four corners, do several rounds of jacking placing a sections of 2x6 under the jack if you can’t set the stands as high as possible. Next get under the car and soak all the exhaust fasteners with PBlaster, to help get them loose and begin to remove the exhaust. This is best accomplished by beginning at the rear of the car and working forward. The exhaust is some damn heavy, so it helps to support just the rear slightly while removing the six nuts from the manifolds. These are copper nuts, and should be replaced when the car is reassembled. They should be 14mm, and if jammed on are easily removed by driving a 13mm socket onto them and then just forcing them off. Also remove the O2 sensor, a great time to replace this if you suspect it to be shot. Separate the pipes from the manifolds, and remove them from the car. It’s not completely necessary to remove them from under the car as getting the pipe flanges past some of the suspension parts is very tough and requires swinging the pipes outward more than most home garages will allow. Finally remove all the heat shields from the body.
Loosen the mounting bolts for the center bearing, mark the relationship of the driveshaft halves, and loosen the connecting collar. Mark the relationship of the driveshaft to the differential input flange, and remove the drive shaft from the differential. Remove the 3 bolts connecting the driveshaft to the flex disk, slide the drive shaft rearward, and unmate it from the transmission. Remove the bolts connecting the drive shaft to the differential. Remove the bolts supporting the center bearing and remove the drive shaft. Try not to separate the shaft’s halves yet, if this happens use the mark to realign them. Improper alignment will lead to noise and vibrations, shortened center bearing life and shortened flex disk life.
Now you’ve got a choice, differential or transmission.
Select 3rd gear. Remove the rear transmission mounts and the sub frame. Disconnect the selector lever from the shift lever, leave it attached to the selector shaft for now. Disconnect the reverse switch, and unbolt the shift console from the transmission. The bolts are two allen head bolts roughly on either side of the selector shaft. Also remove the press fit rear console mount so that it can be replaced. Use the factory part or the fix I submitted to the list archives see, , it is a much more durable and substantial fix from the factory part.
Attach a piece of hose to the clutch slave bleeder nipple, and open the bleed screw to relieve pressure in the clutch hydraulics. This is a precautionary step that results from personal experience, when removing my slave cylinder the rapid release of pressure caused the piston in the master to become disengaged from the shaft requiring replacement of the master cylinder. This condition is not noticeable until final assembly of the motor and transmission. Remove the slave from the transmission bell housing, and suspend it out of the way.
Remove the protective cover from the flywheel sensors, and remove them from the bellhousing suspending then out of the way. Be sure to mark their correct positions, as the motor will not start if they are reversed.
Begin removing the bolts mounting the transmission to the engine, there were 11 on my car but several just secure a inspection cover. If these are the torx head bolts as in my car, be sure to do a good job cleaning them with PB and a rag or tooth brush before attempting to remove any of them. Also there are two different sizes of bolts so be sure to get them right. The nightmare of stripping any of these is something I shudder to consider, as there is almost no room to work with and several are completely blind and must be found by hand alone.
Removal of these bolts will require the use of lots of extensions in combination, and wobbles are required to get at several. The best method consists of trying several configurations of the extensions including placing a wobbly in the middle of several extensions for a couple. Work cautiously; attempt to drive the correct sockets onto the bolts to fully seat the fastener and to shock it loose a bit.
When all the bolts are loosened, support the transmission with the jack then remove all the bolts. Avoid allowing the transmission to hang by the input shaft, it could damage the transmission. Separate the transmission from the engine, this may require lifting the rear of the engine slightly to ease the separation and remating of the transmission. Slide the transmission rearward until the input shaft is cleared and remove it from under the car. Use a rubber mallet, or a piece of 2x4 to break the housing loose if it’s stuck.
Back to the transmission in a bit.
Loosen the bolts holding the pressure plate to the flywheel, then remove them while supporting the pressure plate. Remove the pressure plate and clutch disk from the flywheel.
At this point the flywheel can be inspected to determine if can be resurfaced or needs to be replaced. If it appears that the flywheel can be resurfaced not gouged or warped, bring it to a machine shop and have the minimal cut a cleaning cut, possible done. NAPA, no plug intended, did mine while I waited for about $35.
To remove the flywheel the crankshaft must be blocked in some way. I’ve found two methods that work well. First, obtain a socket and handle large enough to hold the nut on the front end of the crankshaft. Plus the crank can be blocked once with out having to rotate it much at all. Minus, the coolant system must be drained and the radiator removed to accommodate most tools of sufficient size to fit the crank nut.
Second method, use a pair of sockets or wrenches on opposite, or adjacent bolts, while turning the fasteners in opposite directions. Plus, no need to remove cooling parts. Minus, you’ll likely have to turn the motor to get all the fasteners. Both methods work equally well to torque fasteners.
Loosen the flywheel bolts, support the flywheel, remove the bolts, the plate and remove the flywheel. Be careful not to pry, or strike the magnets on the ring gear while removing or handling the flywheel.
Next, use the pilot bearing removal tool to extract the bearing and its covering. Be sure to remove the outer race also. In my car the bearing had deteriorated to such a point that the inner and outer races separated during removal, requiring a second pulling operation. Install the new bearing and cover using a socket of correct size to drive the bearing and cover squarely into the end of the crankshaft.
Remove the bolts holding the rear main seal flange to the block, there are also bolts securing the flange to the oil pan as well. Carefully pry the flange from the block and oil pan. Use care not to damage the oil pan gasket. Use a razor blade or a long thin x-acto blade to help separate the flange and gasket. Clean the mating faces of the flange and block. Drive the old rear seal out of the flange, and install the new seal being sure to seat it squarely. Reinstall the new seal and flange, using care not to damage the seal, and torque down the bolts.
Now it’s time to reinstall your newly resurfaced flywheel. First, thoroughly clean the surface of all cutting oil. Then install the flywheel aligning the locating dowl. Don’t force it, the flywheel only fits one way. Install the plate and NEW FACTORY BOLTS, the factory bolts have a special locking compound on them to prevent them from backing out and are slightly stretched by torquing and are not reusable. Just hand tighten the bolts until they are all in place. Then torque them in a cris-cross pattern. Again you’ll need to block the crank shaft, either of the above methods work well.
At this point you’re ready to install the clutch mechanism. Orient the clutch disk and pressure plate correctly. Put the clutch disk on the alignment tool, and correctly align the disk with the pilot bearing and flywheel surface. You want to be sure that the alignment tool is inserted as far as possible into the pilot bearing. Push the disk up against the flywheel and install the pressure plate, using the pins on the flywheel to correctly orient it. Install the bolts holding the pressure plate to the flywheel using blue locktite and torque the bolts.
Back to the transmission. When I finally turned my attention to the transmission I decided that it was too dirty, covered with a foul mixture of oils, tars, and road grime, to fool with and properly install new seals without damaging them. I cleaned the entire exterior, and inside the bell housing with a high temp pressure washer before I even drained it or pulled a seal. It came out looking brand new. I realize that most people don’t have access to a heated pressure washer but a high pressure DIY car/boat wash and some engine cleaner should do just fine. Cleaning also makes the reinstall a much less messy job.
Remove the throw out bearing, clutch fork. Remove the fork by releasing the spring clip that holds it to the pivot pin.
Remove the selector lever from the selector shaft by sliding the spring ring back and removing the pin. This is a good time to install a short shift kit, as it’s tons easier with all the parts out of the car. Pull the selector shaft seal out and install the new seal.
Next the output shaft seal needs to be removed. To remove the seal the output flange needs to be removed. Removal requires the use of a thin walled deep 30mm socket. If one cannot be found, grind a deep 30mm impact socket to fit. Also I have seen at an auto parts superstore a deep 30mm socket for some US make’s FWD units. It looks as if it may fit, but I don’t know for sure. Block the transmission and remove the nut, lock plate, and the flange. Pull out the seal, and install the new one. Use a piece of pipe to reach over the shaft. The output shaft bearing can also be repacked at this point too.
Reinstalling the output flange requires a two stage torquing. The first stage seats everything properly, and then the second stage which requires loosening and then retorquing is for holding everything together. Also when the flange is replaced on the shaft use a thin coat of blue locktite to seal the splines as they are a source of small leaks. Replace the flange, the lock plate, torque the nut with locktite, and bend the lock plate tabs.
To replace the front seal remove the bolts securing the throw out bearing guide sleeve, remove the sleeve, and carefully remove the seal. Install the new seal, a length of pipe is most helpful in this operation. Reinstall the guide sleeve, use a thin coat of locktite on the sleeve’s mating surface with the transmission case. Note there are at least 2 different types guide sleeves, the difference is in how the sleeve is attached, but the operation is essentially the same except for the number of bolts. Torque the bolts with locktite.
Remove the pivot pin from the bell housing, and install the new one. Put a small amount of moly grease on the pivot pin and return the fork to it’s correct position on the guide sleeve. Completely pack the new throw out bearing with long term moly grease, there is a shallow groove on the inner surface of the bearing that need to be completely filled. Put a thin coat of moly grease on the guide sleeve and install the throw out bearing and correctly orient it with the fork. The ears on the bearing should be vertical. Also put small amount of moly grease on the splines and tip of the input shaft, and the tip of the slave plunger.
Remove the fill and drain plugs, drain the case, and refill it with the gear oil of your choice. Be sure all your clutch surfaces are clean and reinstall the transmission. Also check the transmission case vent to be sure that it is not blocked and that the cover moves freely. Reinstallation is the reverse of removal, be sure to remember to bleed the clutch.
Note I didn’t replace the differential input seal as it wasn’t leaking at all and looked to be in excellent shape.
Engage the parking brake, and begin removing the bolts securing the half shafts to the differential first and then from the final drive hubs. Removal will take a couple of cycles of locking the wheels removing bolts then rotating the wheels and repeating. Remove the half shafts, keep the 3 plates per end, as they need to be reinstalled. The half shafts can be rebuilt and should be if the boots show wear or are split. I found a place that did it for $69 a side or kits are available to DIY.
If you are changing the differential, be sure that the output flanges are the same as the ends of the half shafts. There are as far as I know 2 different flange shapes. One has a flower like pattern on the sides that mate to the half shafts, the other is smooth. The output flanges are interchangeable so just swap them from your old unit if the flanges don’t match your half shafts.
Removal of the differential is not necessary to replace the output seals, but is in order to replace the mount. Disconnect the speedometer pulse sender, place a jack or other support under the differential and begin by removing the 4 forward mounting bolts. The are located on either side, two on top of the housing and two near the bottom. Then remove the bolt holding the rear of the differential to the mount. Some cars may have a bolt that also has a lock nut on the top side of the mount. If this is the case, access the lock nut through the access hole in the trunk under the carpet and insulation.
To replace the output seals. Pry out the output flanges, they come out easily. Remove the snap rings, pull out the seals, then install new seals and snap rings. Make sure the snap rings are fully seated. Reinstall the drive flanges. Drain and refill the differential.
To replace the differential mount simply remove the 4 mounting bolts and replace the mount.
Reassembly is the reverse of removal. Be sure to use locktite on all fasteners and replace any of the bolts joining the half shafts to the drive flanges that may be damaged as they are hex head and strip easily if your tools aren’t seated well.
Driveshaft Center Bearing replacement:
Before separating the drive shaft halves, be sure that you have marked the proper orientation for reassemble. Loosen the locking collar and separate the halves.
Remove the snap-ring, dust cover, and bearing. Replace the bearing, dust cover, and snap ring. Lightly lubricate the splines with moly grease, align the marks and reassemble the driveshaft, tighten the locking collar only enough to prevent the halves from separating while being handled.
When reinstalling the center bearing pre load it before final tightening of the fasteners by sliding it forward slightly, specs call for 5/32-15/64”, and tighten the fasteners.
Put a small amount of moly grease on the locating pin on transmission output flange, install the new guibo being sure that the arrows face the flange arms and not the bolt heads and torque.
Finally, replace all the heat shields and reinstall the exhaust. When reinstalling the exhaust mount the front end of the pipes first and work rearward. This will allow you to position the pipes more easily to align them with the manifolds. Supporting the rear section on my transmission jack was a huge help in placing them.
Replace the tires, remove the stands and enjoy!
Sean 84 633CSi
Transmission Swap Getrag 260 to 265 - "Gene M." <firstname.lastname@example.org>
When the 5 speed transmission on my 86 635 went
out, I planned to do a direct switch it with the 5 speed in my 85 535.
Then I noticed the cars had different looking transmissions and asked
the members of the BCG for information. Turns out that the 86 635 has
the Getrag 260 manual transmission and the 85 535 has the Getrag 265
From the great information from members of the
BCG, it appears that the 265 is an older model and was later replaced
by the 260. However, in 1985 the 265 was put into the 85 E24's and
E28's because of problems with the 260. The 265 is supposed to be "more
robust" than the 260. Gear ratios on the standard U.S. models are about
the same and Bentley's has this information. Bentley's, however,
doesn't tell you how to quickly identify which model you have.
The quickest way to tell whether you have a 265 is that the transmission is attached to four large bolts that are attached to the bell housing with. You will see four 17mm nuts holding the unit onto the bell housing. The 260 bell housing and transmission case is a single intergrated unit.
Other differences are the 265 is longer than the
260. The rear seal on the 260 is seated quite a bit deeper than on the
265. The transmission support mounts are different and they are
mounted in different positions. The mount on the 260 is almost as far
back as the guibo, while the transmission support mount on the 265 will
be further forward. The transmission rubber mount on the 265 is heavier
duty. The shift rod holders are also different. The 265 uses a
sheetmetal holder rather than the aluminum rod style on the 260. The
reverse switch on the 265 is on the driver's side and the vent is on the
passenger side toward the back. The 260 reverse switch is on the
passenger side and the vent toward the front.
The 265 and 260 have the same bolt pattern, but 4 of the bolts are of different lengths. The 4:00 and 9:00 position bolts on the 265 are longer (and have a hex head instead of the male torx head), and the 7:00 and 12:00 bolts on the 265 are shorter than the 260.
If you intend to switch from a 260 to a 265 (or
visa versa), make sure you get all the necessary parts from the donor
car to make the switch. These parts will be:
1. the tranny (also make sure its for a M30 engine and not for a baby six),
2. tranny support with the rubber mounts,
3. shifter holder (you may also want to check/replace the front shifter bushing on the 265),
4. driveshaft (the 265 driveshaft will be too long to fit),
5. bolts to mount the bell housing to the engine (at least the 4 that are different lengths).
Remaining parts like the throw out bearing,
clutch fork, tranny seals and guibo are the same on both. With the
proper parts, the switch is a direct swap. The 265, with its removable
bell housing, is quite a bit easier to get in and out of the car.
One other thing to keep in mind. Tranny identification is important if you plan on ordering a new driveshaft or shifter parts.