pinkpanther
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- Thread starter pinkpanther
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or go after market diff..Newbers said:
All M cars come with LSDs as standard.
Pinkpanther give Phil at CPC Performance Engineering a call, really knowlegable and specialize in engine rebuilds and BMW servicing, they did my rod bearing shells, and repaired my sump when it was damaged, and I now use them for all servicing and maintenance. Really good garage with nothing but M cars inside and out, helpful, honest and great service.
Shaft seal is about £40. Remanufactured diff is about £1800.
If there is play in the input shaft you should be able to feel it by hand, if not hear it when blipping throttle whilst driving.
I'd take it elsewhere if you aren't mechanically minded.
Worst case scenario, get a quaife atb LSD fitted at Bird's for about £1600 all in, a better diff than the clutch type one fitted from the factory, which at 50k will probably have worn clutch plates anyway.
Mike
If there is play in the input shaft you should be able to feel it by hand, if not hear it when blipping throttle whilst driving.
I'd take it elsewhere if you aren't mechanically minded.
Worst case scenario, get a quaife atb LSD fitted at Bird's for about £1600 all in, a better diff than the clutch type one fitted from the factory, which at 50k will probably have worn clutch plates anyway.
Mike
I think you have a good reason to be sceptical.
Without opening up the diff there's not that much to say about the condition, so changing without proper diagnose is tbh not a really professional way to do things.
Do you know what they exactly ment by play? Have you seen it?
Was it axial play? radial play?
How much oil was left in the diff?
The play can be caused by a lot of things, like the flange nut not properly tightened. True that can cause damage to the bearings (those can be changed) or gears, but without opening up the diff thats rather a guessing game. It could be that you only need a new claping bush (thats a £4 part on its own) or that any play has already damaged your pinion/ringgear.
I dont know any UK based bmw diff specialists, but its sure time to get another specialist than the one you have now.
I'm sure there are some UK based companies that specialize in bmw diff refurbishments. Getting the diff there might be a pain because of shipping weight and the possibility that it can leak oil (some parcelservices specifically note that shipping car parts that contain oil is forbidden)
Usually a total refurb costs between 500 and 1k (thats usually cleaning/painting/sandblasting, adjusting/setting tolerances, new seals and (partial?) new bearings). An M diff will be at the higher end of that scale. And if new parts like pinion/crownwheel etc are required that will be more of course.
For these kinds of jobs you musnt go to 'bmw specialists' that do maintenance on cars but to specific driveline/transmission/diff specialists or motorsport oriented shops as fiddeling on a bmw diff is beyond that what is written in the BMW factory workshop manuals (so a 'bmw specialist' or a bmw dealer wouldnt know how to proceed). Its specialized work.
A quaife lsd wont solve this problem as the quaife diff is only the internal diff core. These problems are either related to the bearings/pretention or the crown/pinion.
Without opening up the diff there's not that much to say about the condition, so changing without proper diagnose is tbh not a really professional way to do things.
Do you know what they exactly ment by play? Have you seen it?
Was it axial play? radial play?
How much oil was left in the diff?
The play can be caused by a lot of things, like the flange nut not properly tightened. True that can cause damage to the bearings (those can be changed) or gears, but without opening up the diff thats rather a guessing game. It could be that you only need a new claping bush (thats a £4 part on its own) or that any play has already damaged your pinion/ringgear.
I dont know any UK based bmw diff specialists, but its sure time to get another specialist than the one you have now.
I'm sure there are some UK based companies that specialize in bmw diff refurbishments. Getting the diff there might be a pain because of shipping weight and the possibility that it can leak oil (some parcelservices specifically note that shipping car parts that contain oil is forbidden)
Usually a total refurb costs between 500 and 1k (thats usually cleaning/painting/sandblasting, adjusting/setting tolerances, new seals and (partial?) new bearings). An M diff will be at the higher end of that scale. And if new parts like pinion/crownwheel etc are required that will be more of course.
For these kinds of jobs you musnt go to 'bmw specialists' that do maintenance on cars but to specific driveline/transmission/diff specialists or motorsport oriented shops as fiddeling on a bmw diff is beyond that what is written in the BMW factory workshop manuals (so a 'bmw specialist' or a bmw dealer wouldnt know how to proceed). Its specialized work.
A quaife lsd wont solve this problem as the quaife diff is only the internal diff core. These problems are either related to the bearings/pretention or the crown/pinion.
pinkpanther
New member
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pinkpanther said:
The input shaft should not be able to move in either axial or radial direction.
However a little bit of rotational play is permitted but thats very little. This is the play between the teeth from the pinion and crowngear and its called backlash. Maximum permitted backlash is I think 0,20 mm for the M diff.
Liverpool
I'm on my 2nd diff at 150,000 miles.
1st paid for by BMW as it was under warranty. I hadn't slotted anything amiss, but the dealer called me whilst it was in for an inspection and asked whether I'd be okay with them requesting a warranty repair for the unit...I didn't argue.
2nd was mostly paid for by the insurance company after my pre-Christmas accident in 2015. Seems the lateral impact transferred some damage through the driveshaft and diff...so after a few months back & forth between their engineer and my engineer, it was agreed that I'd pay 1/3 of the cost.
The insurance engineer was adamant that the diffs in similar cars (e.g. M3s) rarely made it past 80k miles, and that was why they were initially refusing to contribute.
1st paid for by BMW as it was under warranty. I hadn't slotted anything amiss, but the dealer called me whilst it was in for an inspection and asked whether I'd be okay with them requesting a warranty repair for the unit...I didn't argue.
2nd was mostly paid for by the insurance company after my pre-Christmas accident in 2015. Seems the lateral impact transferred some damage through the driveshaft and diff...so after a few months back & forth between their engineer and my engineer, it was agreed that I'd pay 1/3 of the cost.
The insurance engineer was adamant that the diffs in similar cars (e.g. M3s) rarely made it past 80k miles, and that was why they were initially refusing to contribute.
I have seen the E46 M3 wear input shaft bearings, the play in the flange can be felt with the prop removed ..
Seal wear is common, but indicated by a small mist around the diff and sometimes on the underpan of the car..
I would suggest a big leak "all of a sudden" could easily be something more ..
That said
£4K is ridiculous on price, you can get a refurb with fitting around £2500.. it's no big deal to fit one ..
Seal wear is common, but indicated by a small mist around the diff and sometimes on the underpan of the car..
I would suggest a big leak "all of a sudden" could easily be something more ..
That said
£4K is ridiculous on price, you can get a refurb with fitting around £2500.. it's no big deal to fit one ..
Leaking Diffs are apparently common on these cars.
The tray does a good job of catching the oil so id imagine if its dripping off the tray then its lost a considerable amount.
I have just had the input and 2 draveshaft seals replaced at my local BMW specilist for £300, so even £500 to replace the seals sounds rather steep...
I can also advise that he E46 M3 diff is different to the Z4M diff, both in part numbers and construction, there are a couple of detailed threads on M3 cutters and American forums showing difference in the outer cooling fins and the internals of the diff. The Z4m diff is far "beefier" than the M3 diff.
The tray does a good job of catching the oil so id imagine if its dripping off the tray then its lost a considerable amount.
I have just had the input and 2 draveshaft seals replaced at my local BMW specilist for £300, so even £500 to replace the seals sounds rather steep...
I can also advise that he E46 M3 diff is different to the Z4M diff, both in part numbers and construction, there are a couple of detailed threads on M3 cutters and American forums showing difference in the outer cooling fins and the internals of the diff. The Z4m diff is far "beefier" than the M3 diff.
indeed, its got to be worth trying the cheaper option first - a 50p sized drip from a diff is hardly pouring out. possibly even before you change the seals I'd get the diff drained and refilled to the correct level, and make note of how much came out, and how much went back in again. then put some cardboard under a regular parking spot so you can see how quickly it is leaking.
mad4slalom
Senior member
I had dif input shaft seal done a while back as i had the bit of oil misting, they had to drop the exhaust and prop, it was not a big job or a big bill. About three hundred i think but that was 2 years ago. If no noises i would go for seals an see what happens or get a second opinion. When i first got the m , i noticed a diff clunk occasionally, which is not uncommon, i think it was if you did a fast gearchange and mis timed the clutch, it was just that I was not used to the car and never got it after that. 
as above its boxes off job but pretty routine job for a decent indy