ADVrider (
-   GS Boxers (
-   -   Cracked R1100GS Transmission Case (

MJ Gurunathan 05-26-2012 07:27 AM

Cracked R1100GS Transmission Case
Hi there everyone.

I have a question that I would like to ask. I ride a 1994 R1100GS that has been absolutely brilliant till... now. You've probably guessed by reading the thread title that the transmission housing (where the RHS swing arm pivot threads into the case) is cracked.

This happened when I sent the bike in to my local dealership for a clutch replacement; apparently the pin seized in the threaded hole; in an effort to remove it the technician used a breaker bar and a cheater bar on top of that and *crack* went the transmission housing.

Here's a picture of the damage:

<a href="" title="DSC03288 by MRF3343, on Flickr"><img src="" width="500" height="375" alt="DSC03288"></a>

I'm not sure why they didn't stop and drill the pin out, but that's a story for another day. The dealership will not pay for the damage (despite much slamming of palm on table) so I am left to fix this problem myself.

Here are my options and my opinions on them:

1) Purchase a used transmission: the workshop supervisor tells me that the following transmissions will fit my bike: M94 or M97. I've read Mr. Anton Largiader's website and this seems like a good solution, but I am having trouble finding M97 transmissions in good nick. Used transmissions are not available where I live (I'm in Singapore).

2) Purchase a transmission housing and use the internals from my transmission: this seems like the best thing to do. This will also allow me to rebuild my current transmission, increasing reliability and improving the shifting (I have a problem with the bike skipping from 2nd to neutral and engaging first from neutral without feathering the clutch).

The problem with this is that I do not know which transmission housing will fit the internals of my current gearbox. As far as I understand, the housings from all years are externally the same, but the internals differ depending on the type of input shaft and bearings used.

3) Weld the cracked area and carry out an insert-repair on the threaded hole: this seems do-able, but I have to make sure that the work done is tip-top or else I'll end up with more problems. There is also the possibility of the case distorting during welding.


Given that my GS was produced in 1994, what sort of gearbox housing would fit the internals of my current gearbox?

Are there any other solutions that you would recommend?

I appreciate any and all advice; I'm hoping to compile a little gearbox FAQ and maybe an interchangeability matrix of sorts, but I am short of information... hence my post.

Thanks in advance for all your help!


street_moto 05-26-2012 08:10 AM

Sorry to hear about your trouble and I can't offer any advice about repair or replacement, but I'd say that it's the dealer/mechanics fault and I'd be expecting them to sort it out. Something should have told the mechanic/expert who you paid good money to effect a repair on your vehicle, that something was amiss when he had to extend the breaker bar. Any dope would know that something would break, it's only alloy for goodness sake! Looks like he just used brute force to extract the pin rather than heat it up to soften the Loctite on the thread. Hope you get sorted!

malloy 05-26-2012 08:21 AM

MJ - You are a true gentlemen for not naming the dealer here but I am sure inquiring minds want to know:D. I'd contact BMW NA as clearly the dealer, not you, did the pooch. You went to them for their expertise. It was in their care and custody. You didn't break it. They did! OUTRAGEOUS:eek1. Run, don't walk, from the heavy handed techs therein. Maybe you are better off not going back there.

I had a cracked case with internal bearing failures out of warranty on an R1200GS. It was cheaper (although certainly not cheap) to replace the entire transmission - OUCH.

I'd check with Anton Largiader, an inmate here and generous contributor: Very knowledgeable man.

Or Ted Porter: His shop does a lot of transmission work.

Or BeemerBoneyard: for parts and/or information.

Where are you? Fill in your profile.

Good luck.

TUCKERS 05-26-2012 11:41 AM

Too bad.

I don't believe the mechanic.

This breakage is not uncommon due to torque values being EXTREMELY DIFFERENT on either side of tranny for those fixtures, and mechanic makes big mistake.

If you buy a used tranny you are going to overhaul it anyway. So either a used tranny or used case will cost you the same in the end.

Check with mechanic about torque specs for those fixtures and ask what he use. Don't tell him, but look in manual, I believe there is over a hundred pound difference, Yes that much or more!

Shop is bad and a liar.

bloc 05-26-2012 12:08 PM

OP said he was in Singapore.. doubt BMWNA would be of much help, unfortunately. Posting the name of the dealership may help others in your location though.. what BMW tech doesn't know to apply heat to loosen the loctite?

MotorradMike 05-26-2012 02:05 PM

They broke it due to incompetence, they should fix it.

This may cheer you up a bit.

vagueout 05-26-2012 04:27 PM

MJ, this being an official BMW workshop they have failed in a very basic task OR have been very unlucky (it happens) BUT they are responsible. If they fail to look after you name and shame relentlessly on the net, youtube etc to teach the bastard a lesson in good business. If you are left to wear it, the repairs you mentioned are all doable if you did the work yourself, to have it done properly by someone will be very expensive, and you are not going to trust the shop you already dealt with. If i was in your position, mindful that you are in Singapore, i would be looking for a used g/box from a later 1100 (m97) likely from the U.S. or even australia. Wishing you the best in this drama.:yikes

MJ Gurunathan 05-27-2012 08:30 AM

Thank you all
Hi everyone!

Thanks so much for the great replies, they've been most helpful. I also appreciate the advice given with regards to dealing with the dealership.

For your info, I'm located in Singapore. I've updated my profile as suggested... and you can easily tell I'm a 2-stroke nut! This GS (Chocolate is her name) is my first BMW and I love her to bits.

I'm actually a mechanic by training, I work in a factory servicing turbomachinery. I've always done all of the work on my motorcycles and believe in the old adage, "If you want a job done well, do it yourself." I've just started night classes at the local university and that, coupled with some really long shifts/overtime at the factory leave me no time to work on my bikes. I've therefore had to send them to various places to be fettled...

I've not had very good experiences with the local BMW dealership; I will be honest with you all, I am not a well-to-do person and me and my old GS aren't exactly given star treatment there. The dealership refuses to pay for the damage because my motorcycle has no prior service history with them and in their words, "The previous mechanic must have cross threaded the pivot pin or used the wrong type of Loctite, that's why the case broke."

I am not an idiot, though and any mechanic would know to STOP when dealing with a seized fastener in an aluminum alloy part. I have access to a radial drill so I could have easily drilled the pin out if they had just called me up and told me that the bloody thing was seized and they couldn't get it out.

My primary aim is to get my dear machine out of the workshop as soon as possible, so based on your advice I shall check this matter out with Anton/Ted Porter/Beemer Boneyard.

I may have a good deal on a used transmission from a wrecked R1100RT; it is my understanding (via Anton Largiader's website) that the transmissions on all models (with the exception of the R1100S) are interchangeable, so I shall investigate that route. In any case, my motorcycle has more than 110,000 miles on it so I think it might be wise to get a decent transmission with low miles on it, just to preclude any issues.

I will update you guys when I get more info; I'm quite new to BMWs and I know how frustrating it can be dealing with a lack of information. Maybe we can get some kind of transmission FAQ up and running to help others in similar predicaments.

Thanks again for all your help, ADV rocks!

TUCKERS 05-27-2012 05:02 PM

I am pretty sure the RT box has 'longer legs' your GS has short legs for off road useage. Nothing wrong with the longer legs, better gas mileage and lower RPM at high cruising speeds.

Whale Rider 05-27-2012 05:25 PM


Originally Posted by TUCKERS (Post 18779133)
I am pretty sure the RT box has 'longer legs' your GS has short legs for off road useage. Nothing wrong with the longer legs, better gas mileage and lower RPM at high cruising speeds.

Gerabox Ratios should be the same but the final drive ratios vary between GS & RT
1100 GS 3:1
1100 RT 2.78:1

TXjames 05-27-2012 05:51 PM

I have a used M96 gearbox case with intermediate and output shafts (no input shaft). I think yours is an M94 but if an M97 will work then so will the M96 I have. The bearings in the M96 were tapered, not sealed, but the case is the same. The taper bearing has an outer race diameter that matched that of the sealed bearing in later models. I'll make you a great deal on the case. PM me if interested.

EDIT: As others have mentioned, the tech made a HUGE mistake and it is all his fault. Those bolts are known to be very difficult to remove due to the red loctite used from the factory, large steel bolt torqued pretty tight and a soft aluminum case. Heat and patience required.

Teager 05-27-2012 08:22 PM

I just put a transmission from a R1100R in my 96 1100GS a couple weeks ago and it's working great. Thank's again Robb. The gearing differences are in the final drives not the transmissions. Bottom line; $300.00 vs. a lot more I didn't have to spend. Good luck.

Peka 05-27-2012 11:04 PM


Originally Posted by MJ Gurunathan (Post 18771506)
This happened when I sent the bike in to my local dealership for a clutch replacement; apparently the pin seized in the threaded hole; in an effort to remove it the technician used a breaker bar and a cheater bar on top of that and *crack* went the transmission housing.

They mustn't have read in the manual where it says to heat it before trying to loosen that pin :rolleyes

Pekkavee 05-28-2012 03:42 AM


Originally Posted by Peka (Post 18780919)
They mustn't have read in the manual where it says to heat it before trying to loosen that pin :rolleyes

Quite right. It has to bee very hot before you even touch the pin.


slartidbartfast 05-28-2012 03:48 AM

You can try asking them if they heated the pin to soften the thread-lock compound before trying to remove the pin (that's the procedure per the factory manual.) I expect they'll lie about it once they check but it might be worth asking the tech directly and see what he says.

Times are GMT -7.   It's 05:57 PM.

Powered by vBulletin® Version 3.8.5
Copyright ©2000 - 2015, Jelsoft Enterprises Ltd.
Copyright ADVrider 2011-2015