Diff backlash after billet diff mount install

[ajm55]

A few months back I installed the GAW billet diff mount. Following the installation I noticed some diff whine. It’s mild but certainly audible from the driver seat. GAW advised that this is not uncommon given the absence of the stock bushes on the GAW unit.

Not long after the instal, I began noticing what sounds a lot like diff backlash. That issue seems to be getting worse. I’m going to re-instal the stock diff mount to assess its impact, if any, on the two issues. In the meantime, I’d be keen to hear whether others using the GAW diff mount have experienced either or both these issues

[TinCanSailor]

Appreciate your sharing this information. I am about a month out from installing my diff brace from rkautowerks which reuses the stock bushing. Maybe run your diff brace with the stock bushing vs the derlin bushing from GAW.

[Doctor_X]

The issues you’re reporting are the main downfall of the GAW mount - the solid delrin bushing signicantly increases cabin noise transmission.

[ajm55]

Yep, if I had known at the time about the impact of the delrin bushing, I would have opted for the RK unit instead. TinCanSailor, I'd consider doing what you suggest but not sure that's even possible

[TinCanSailor]

Originally Posted by ajm55

Yep, if I had known at the time about the impact of the delrin bushing, I would have opted for the RK unit instead. TinCanSailor, I'd consider doing what you suggest but not sure that's even possible

Man, sorry to hear that. I've always had a hard time with urethane bushings most of the time it was just a comfort issue but when you start hearing new noises you gotta investigate. Hopefully you caught this early enough to head off any real trouble.

That said I am curious about the question you posed regarding diff rebuilds. I have seen anything on this topic before. amybe hit the folks up at seemslegitgarage.com. They do a lot of DCT work.

[bmwmike89]

I had this exact issue with mine when I first installed it. I had a local shop to me install it as German Auto Werks is about 3hrs from me. Upon first install I had greatly increased differential whine noise. It was so loud that even with the radio on I could hear it. I thought for sure the mount was the problem. Contacted GAW and they told me to bring the car to them to look at. I went for a test drive with the owner and he stated it most certainly is not supposed to be this loud and something was wrong. They removed and reinstalled it and sure enough no more noise. They stated most people dont look at the directions they supply. These are the directions from BMW directly for the oem bracket. It's highlighted if not followed properly it can cause increased noise and that's with the stock bracket/bushing. So most certainly installing wrong with a delrin bushing can cause increased noise.

Not saying this is you're issue but it's the issue I had and something to at least look into.

[BBHMM]

Damm i just bought GAW mount. Now Im not sure if i want them to install it or return it and buy RK mount🤷🏻*♂️🤷🏻*♂️

[ajm55]

Originally Posted by bmwmike89

I had this exact issue with mine when I first installed it. I had a local shop to me install it as German Auto Werks is about 3hrs from me. Upon first install I had greatly increased differential whine noise. It was so loud that even with the radio on I could hear it. I thought for sure the mount was the problem. Contacted GAW and they told me to bring the car to them to look at. I went for a test drive with the owner and he stated it most certainly is not supposed to be this loud and something was wrong. They removed and reinstalled it and sure enough no more noise. They stated most people dont look at the directions they supply. These are the directions from BMW directly for the oem bracket. It's highlighted if not followed properly it can cause increased noise and that's with the stock bracket/bushing. So most certainly installing wrong with a delrin bushing can cause increased noise.

Not saying this is you're issue but it's the issue I had and something to at least look into.

yeah, thanks. Doubt this this applies in my case. A mate installed the unit. I watched and read out the instructions to him step by step

[BBHMM]

Originally Posted by ajm55

yeah, thanks. Doubt this this applies in my case. A mate installed the unit. I watched and read out the instructions to him step by step

How he like it?? Any noise that everyone talking about???
Can anyone share sound clip with that diff noise??

[ajm55]

Originally Posted by Bmyguy88

After GAW reinstalled mine I have no complaints. I did my research and messaged quite a few of their customers before buying. All of which had no conplaints. Yes it's not as quiet as oem but I'm after all out performance vs comfort. In my eyes it's a small price to pay to have piece of mind it won't break. I don't think my phone will pick up the increased noise as it's not very loud. It's a slight diff whine noise. I can only faintly hear it without the radio on. Once it's on I can't hear it at all. Also I'm still stock exhaust. Once I put on my Akrapovic exhaust I'm sure I'll never hear it.

Yes, its not great but not unbearable. I'd rather have no diff whine but put up with it for peace of mind. With the radio on, its not noticeable unless you're at very low volume and specifically listening out for it

[Doctor_X]

Question

For those who have posted that believe the OEM bushing in the RK mount is prone to failure - beyond what you were told by GAW, has anyone actually seen this happen?

[Bmyguy88]

Originally Posted by Doctor_X

Question

For those who have posted that believe the OEM bushing in the RK mount is prone to failure - beyond what you were told by GAW, has anyone actually seen this happen?

When I contacted past GAW customers for reviews when I was considering what mount to go with there was one customer who stated his failed on his stock mount and was the main reason he went with the GAW. Also GAW did have pictures of mounts with failures that where not from them but their research before making the mount.

[Flo1989]

Originally Posted by BBHMM

Damm i just bought GAW mount. Now Im not sure if i want them to install it or return it and buy RK mount🤷🏻*♂️🤷🏻*♂️

Same here. ajm55 has me a bit hesitant to intall mine as well but I think I'm gonna go for it. Talked to a guy outside of the forum who has it and he has zero regrets. And if you can't hear it with the music on low, there shouldn't be any reason why us with aftermarket exhaust should hear it.

ajm55 Can you elaborate on what you mean when you said "diff backlash"? On up/down shifts?

[Doctor_X]

Diff bushing failure was and has been an issue on the non-M F10 models. On the M5, it’s not a common failure point.

RK first built their diff mount with delrin bushings identical to the GAW unit. They soon pulled the delrin and recommended stock because of the noise, vibration, and lack of appreciable benefit.

The GAW mount is an extremely quality product - but it’s noisy. That’s the only downfall.

[TinCanSailor]

Originally Posted by Bmyguy88

When I contacted past GAW customers for reviews when I was considering what mount to go with there was one customer who stated his failed on his stock mount and was the main reason he went with the GAW. Also GAW did have pictures of mounts with failures that where not from them but their research before making the mount.

Hey is talking about the bushing that goes in the mount.

[Bmyguy88]

Originally Posted by TinCanSailor

Hey is talking about the bushing that goes in the mount.

Correct. I'm talking about the stock oem rear differential bracket bushing. I've talked to someone who had it fail on them and GAW also had multiple pictures of other people's failed oem rear bracket bushing. I'm not talking about the mount itself I'm referring to the bushing only.

[TinCanSailor]

Originally Posted by Bmyguy88

Correct. I'm talking about the stock oem rear differential bracket bushing. I've talked to someone who had it fail on them and GAW also had multiple pictures of other people's failed oem rear bracket bushing. I'm not talking about the mount itself I'm referring to the bushing only.

Crazy. I can't imagine the level of abuse that thing would have to take to fall apart but hammer something enough and you can. Maybe from a dead stop to WOT.

[ajm55]

Originally Posted by Flo1989

Same here. ajm55 has me a bit hesitant to intall mine as well but I think I'm gonna go for it. Talked to a guy outside of the forum who has it and he has zero regrets. And if you can't hear it with the music on low, there shouldn't be any reason why us with aftermarket exhaust should hear it.

ajm55 Can you elaborate on what you mean when you said "diff backlash"? On up/down shifts?

i'm referring to the thud you hear when getting on or coming off the throttle while travelling at low rpm in a high gear.

[m5dream]

any more updates on this mount has more people used it with more feedback??