Differential Shims

[TylerBrown]

It appears BMW no longer sells diff shims for our car. I found Racing Diffs sells shims but shipping is around 21 days from Serbia (their location) to the USA.

Does anyone have other sources for diff shims? I checked ebay but I couldn’t find any sourced from the USA.

[Cubieman]

https://diffsonline.com/custom-performance-differentials/

[TylerBrown]

Thanks for the link! I forgot to mention I checked Diff Online and they want $500 for shims. I can't fathom why shims would cost anywhere near that much aside from the age-old "BMW tax."

[CrookedCommie]

Thanks for the link! I forgot to mention I checked Diff Online and they want $500 for shims. I can't fathom why shims would cost anywhere near that much aside from the age-old "BMW tax."

I have an unused set of racingdiff shims. PM me an offer.

[TylerBrown]

I have an unused set of racingdiff shims. PM me an offer.

I PM’d you. Thanks for reaching out!

[Arith2]

Can we get the dimensions of OEM shims? Shims are just shims. There's nothing special about them

[TylerBrown]

We probably could. Aside from capitalism, I don’t understand why 10 shims would ever cost $500.

[Arith2]

We probably could. Aside from capitalism, I don’t understand why 10 shims would ever cost $500.

Chevy and Ford shims are like $10. If we can find them in the same size, then we can post it here. I don't have a diff to take apart and measure radius of the shims. Even getting some made at a machine shop would be cheaper.

[EZE]

Are the racingdiffs shims a different size? They call them "free play delete" shims on their site.

Also CrookedCommie did you install a set of their rebuild kits and any feedback?

This is the kit for reference:
https://www.racingdiffs.com/collecti...34090515529863

They have a video up to rebuild your own diff with stock gearing I was thinking of giving it a shot but wanted to gear my diff to 3.91.

[///Mac]

I recently rebuilt my diff with 4.10 gear set and installed Racing Diffs' LSD clutch pack + "free play fix shim" while I was in there. Somewhere in the item description on eBay, they mention DHL shipping is available at additional cost upon request, so I contacted them to arrange that. They stated that due to Covid-19 interrupting standard shipping reliability, they've been shipping all orders via DHL at no additional charge. If that's still true, you can expect to receive the shipment in 4-5 calendar days from ship date regardless of the dates in the eBay listing. My order was shipped on a Friday and delivered Tuesday using the free shipping option.

I had a pretty serious "M clunk" from my diff before the rebuild and it's completely gone now. I replaced everything in the diff with exception of the LSD carrier and spider gears, and obviously set backlash and preloads within tolerance. I'll never know if the clunk would have been resolved with the fresh OEM parts alone or if the "free play fix shim" did it. There's still a noticeable amount of free play in the right axle and no clunk, so I think the clunk would have been eliminated with the rebuild alone. Diff bushings were also replaced which may have helped too, but the originals didn't look bad and probably didn't contribute to the clunk in the fist place.

Due to the ridiculous cost of the shim kit I didn't order them hoping I'd be able to sneak by with the originals. Luckily my diff needed thinner shims for proper preload, so I cheated and planed the original shims down little by little until they were perfect. I don't know if that's advisable, but seems to have worked so far.

I don't have any feedback on the LSD clutch plates yet. I'm still in the break-in period for the new gears and haven't driven her hard yet.

[///Mac]

Are the racingdiffs shims a different size? They call them "free play delete" shims on their site.

The "free play delete" shim is installed in the LSD unit to minimize slop in the right axle. This design is unique to the Racing Diffs shim, but it's not the same shim referenced by the OP. The OP is talking about the shims that go between the right and left output flanges and the diff case which set the correct carrier preload.

[CrookedCommie]

Are the racingdiffs shims a different size? They call them "free play delete" shims on their site.

Also CrookedCommie did you install a set of their rebuild kits and any feedback?

This is the kit for reference:
https://www.racingdiffs.com/collecti...34090515529863

They have a video up to rebuild your own diff with stock gearing I was thinking of giving it a shot but wanted to gear my diff to 3.91.

I put in one of their rebuilt ZF 4 clutch units. I have no feedback because the track car has not been on track yet this year.

[TylerBrown]

The racingdiffs shim sizes are 1.0mm to 2.0mm. They worked fine and were a lot cheaper than diffsonline.

[EZE]

Thanks all, I’ll get the racing diff set and try them out on a 3.91 rebuild.

[Arith2]

I recently rebuilt my diff with 4.10 gear set and installed Racing Diffs' LSD clutch pack + "free play fix shim" while I was in there. Somewhere in the item description on eBay, they mention DHL shipping is available at additional cost upon request, so I contacted them to arrange that. They stated that due to Covid-19 interrupting standard shipping reliability, they've been shipping all orders via DHL at no additional charge. If that's still true, you can expect to receive the shipment in 4-5 calendar days from ship date regardless of the dates in the eBay listing. My order was shipped on a Friday and delivered Tuesday using the free shipping option.

I had a pretty serious "M clunk" from my diff before the rebuild and it's completely gone now. I replaced everything in the diff with exception of the LSD carrier and spider gears, and obviously set backlash and preloads within tolerance. I'll never know if the clunk would have been resolved with the fresh OEM parts alone or if the "free play fix shim" did it. There's still a noticeable amount of free play in the right axle and no clunk, so I think the clunk would have been eliminated with the rebuild alone. Diff bushings were also replaced which may have helped too, but the originals didn't look bad and probably didn't contribute to the clunk in the fist place.

Due to the ridiculous cost of the shim kit I didn't order them hoping I'd be able to sneak by with the originals. Luckily my diff needed thinner shims for proper preload, so I cheated and planed the original shims down little by little until they were perfect. I don't know if that's advisable, but seems to have worked so far.

I don't have any feedback on the LSD clutch plates yet. I'm still in the break-in period for the new gears and haven't driven her hard yet.

Any update on the rebuild?