Powerflex poly diff bushing failure

[bmwfnatic]

Wtf lol, I was buying covers for well under 200, shame…

[Flow]

FWIW, with the Powerflex diff bushings, I cross threaded the front diff bolt on a car as nothing was lining up.
Nothing from that brand will go on my car that is certain.

[Obioban]

e36 is softer, but still a better option than poly.

Poly always sucks.

[bigjae46]

Here is why that happened...it's poly. It is like I have two options. Let's take the shittiest traits from those options, combine them into one....that's poly.

[enjoy_m3]

I've used e36 m3 diff cover bushings on a street car that's setup for track. No issues paired with rogue front diff bushing. Had it on my e46 m3, now my z4mc.

[SteelGreyM]

Here is why that happened...it's poly. It is like I have two options. Let's take the shittiest traits from those options, combine them into one....that's poly.

Somehow I missed the poly is garbage FYI. Thought they really lasted forever.


Everything OEM is just leaps and bounds better. I'm slowly swapping out all these little aftermarket touches I've put on the car over the years.

There is a bright side to all this. I'm finally getting to take the exhaust off the car and swap out the stupid aftermarket (surprise) resonator that has somehow crumbled from the inside out and made an annoying rattle.

[Nate047]

How's the front diff mount looking after 3 years?

[Ramps]

I’ve been running OE E36 bushings for about few years and they’re great, I didn’t notice any difference from stock to be honest.

[eacmen]

I don't know who makes the poly diff bushings that the previous owner put on the car but they have held up well with no issues. They are red so maybe AKG?

Not all poly is created equal. And powerflex is one of the worst ones. I had a set on the old m3 that lasted one track event.

[Altaran]

I don't know who makes the poly diff bushings that the previous owner put on the car but they have held up well with no issues. They are red so maybe AKG?

Not all poly is created equal. And powerflex is one of the worst ones. I had a set on the old m3 that lasted one track event.

Red could be AKG's hard compound. They don't really dampen at all, so you should hear the diff in that case. (If you still have interior, then it's not so bad)
But they will still fail. I put them in when I was young and stupid, they failed. I went solid.

Generally poly bushings are crap, because they are made for easy installation. OEM bushings or solid ones require a lot of force to put in. That's why they stay in place. Poly you only need a soft hammer, how is that supposed to hold under the stress of the drivetrain?

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[DJAM3]

Red AKG bushings are 75D. Much harder than the standard powerflex bushings. They're basically as hard as Delrin. I ran the 75D FCAB, RTAB, and tranny mounts on street for almost 2 years and 1 track day. Looked new when removed.

[oceansize]

For the diff on a pure street car poly/solid of any sort makes no sense.

[Obioban]

Yep.

Poly/solid diff mounts probably have THE worst ratio of nhv/performance gain this side of a muffler delete. Makes no sense for a car that sees any street use.

[SteelGreyM]

How's the front diff mount looking after 3 years?

Just starting to crack but not as bad as the rear. Would estimate complete failure within another 100 or so miles of hard driving

Should be noted that I'm talking 3 years and less than 3000 miles

[SteelGreyM]

I've been running OE E36 bushings for about few years and they're great, I didn't notice any difference from stock to be honest.

Now that I remember I had e36 diff bushings pressed in while I did my subframe. Put 30k good miles on those and they performed just fine and weren't even toast when I pulled the diff last. Switched to poly on a whim since I had the diff out