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04-06-2021, 06:51 PM | #1 |
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rear diff bolt keeps braking.
My rear diff bolt keeps snapping. ive replaced it twice now going on the 3rd time. i cant seem to find anywear with a stronger bolt or a support bracket to help prevent this. If anyone has found a cure for this please lend my some insight. thanx
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04-06-2021, 07:13 PM | #3 | |
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It seems the problem hasn't been sorted yet. Others had the same experience |
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04-07-2021, 05:55 AM | #4 |
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diff bushings.
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2011 Frozen Black/Fox Red E90 M3 650+WHP
G-Power Supercharged First DCT to Manual Conversion Worldwide KW CS, BBS RI-A, BW Headers, Snow 2.5 |
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04-12-2021, 07:53 AM | #7 |
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Very noticeable, especially when you're pressing or letting off the throttle (clunks as the driveshaft bounces around). This guy's diff bushings must be made of jello and he must be launching hard daily
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04-13-2021, 04:37 PM | #8 |
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04-13-2021, 06:23 PM | #9 |
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Not exactly related to abuse, it's been happening to others too. MRF claimed they were making some reinforcement of some sorts then it went quiet. It seems to be a rare flaw some of these cars have that's recurring. There is another thread in here.
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04-13-2021, 07:05 PM | #10 | |
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04-13-2021, 07:18 PM | #11 | ||
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https://www.bimmerpost.com/forums/sh...php?p=26705163 |
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04-13-2021, 07:47 PM | #12 | |||
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Good except from AKG Motorsports to keep in mind. "Remember: The material used for the subframe bushing location(s) must match the material used for the diff mount bushing(s)."
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04-13-2021, 08:02 PM | #13 |
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The rear bushing is not foam. It is solid aluminum with a roughly 1/8” thick foam sleeve. I think the problem that a few people have experienced is related to more than just that single rear bushing.
I don’t think the subframe and diff bushings have to match. You can run solid or very stiff (like Delrin or 75D poly) subframe bushings with stiffer than stock diff bushings like 80A or 95A or 75D poly. It’s the stiffer diff bushings that cause the whine, not the stiffer subframe bushings. I run 75D subframe and 95A diff bushings. There is whine, but it is tolerable to me. I would not go any stiffer on the diff bushings. I did drive a convertible with solid subframe bushings, however, and thought the whine was tolerable. Maybe the convertible is better insulated? |
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04-13-2021, 09:58 PM | #14 | |
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Of course you can do whatever you want, that's just what's advised by this specific race parts company. Lots of folks running solid sub and softer diffs to minimize whine. But you're not solving the problem of movement if you're launching the car.
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