How long to check gearbox input / output bearings?

[Richard Russell]

I've had my '94 1100GS for about 5 years, and in all that time it's had a rattle in neutral that disappears when the clutch is pulled in. Several people on here have asked about similar noises, so I guess it's relatively common. I wasn't too worried, as it never got any worse... ...until now.

Now the rattle has become noticeably louder, and has developed a worrying whining noise to go with it that sounds like a failing bearing. After reading Tarka's experience I reckon I need to check it out!

Can anyone give me any hints on how long it should take to remove the gearbox and check the input and output bearings? After a quick flick through the Haynes book I'm guessing it will take me quite a while just to remove all the other stuff first (tank, airbox, throttle bodies, exhaust, rear subframe, etc).

Any pointers welcome!

Thanks,

Richard

 

[dazco]

you should be able to get the box out within 2 hours easy. Its a pain in the ass stripping it all down but no big hardship(even i managed it)
As i remember, all the electical connectors are different so theres no worry about getting them mixed up(but i still labeled them all)
the trickiest part is splitting the box from the engine.
If its not been off before it could be quite "stuck"
nice gentle, but persistant tapping around the join line with a soft faced hammer and the application of a bit of WD40 helps, and make sure youve got a trolley jack under the box for when it splits.
As for actualy checking the bearings someone else had better give you some pointers on that one.

 

[ciderman gs]

i belive the sub frame can be left bolted to the frame so there are just two bolts holding it then lift the sub frame and strap up out of the way this then gives access to the gearbox without removing all the stuff bolted to the sub frame so i think. as too the bearings if you are going to remove them to check them you may as well replace them with new hope this helps i sure somebody will put me right if i am wrong.

andy

 

[Tarka]

After reading Tarka's experience I reckon I need to check it out!

You do indeed.....get it sorted ASAP.

 

[Rob Farmer]

Richard the case hardning on the taper roller bearings have gone tits up. You can get the early gearboxs upgraded to the 97 spec doing away with the dodgy taper roller bearings.

Basically up to 96 the boxes rattled at tickover due to the gears rattling. In 96 they fitted O rings to stop the rattle but this caused a clunky gearbox because the gears slowed down too quick. so they changed them again in 97 - the final rev of the gearbox was 98/99 and they were quite well sorted. Then they bought out the 1150 that didn't have niggly gearbox problems...they just blew them to pieces by selecting two gears at the same time

If you fancy a read about the different boxes then have a look here http://www.micapeak.com/bmw-gs/trans.html

Audi gearboxes (also made by Getrag) from the same era suffered from the same problem due to the taper rollers

The bottom line is it's bolloxed and needs fixing ASAP

 

[Richard Russell]

Thanks for the replies chaps. I've taken the gearbox off and taken a look inside, and sure enough there is some scoring on the taper rollers and the corresponding race for the input shaft bearing. I only looked at one bearing, as I didn't have the time or inclination to take the innards out to check the other. I'd seen enough. The (non-taper roller) bearings on the intermediate and output shaft seemed nice and smooth with no play, so I guess it would still be possible to change just the input shaft.

However the Haynes book says checking the shaft preload is a job for a dealer. Anyone got a view on this? Maybe I should take it into a dealer and get them to swap the bearings for me?

I think on balance swapping it for a post-97 gearbox is the better option, although quite a bit more expensive. Anyone got one? Motorworks may well have one, but at a price.

Rob, is this what you meant when you mentioned getting the gearbox upgraded? Or is there someone who will upgrade my existing box to 97 or post-97 spec?

By the way Dazco... two hours? It took me the best part of two whole evenings. You had me going for a while there, but I suppose it was April 1st

 

[ktmmark]

You can fit later bearings to your box(except 1) & to remove the box fit a clutch & refit geardox takes 3 hrs