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Old 08-16-2016, 06:42 PM   #1
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Default Rear dif bushing explosion?

So who here has came across your rear dif bushings literally exploding and dropping the dif from the car? I had old oem ones that came in my rear dif setup i bought and i never thought to change them I guess that was a mistake. Am I the only one or maybe something else caused this?
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Old 08-17-2016, 04:20 AM   #2
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So who here has came across your rear dif bushings literally exploding and dropping the dif from the car? I had old oem ones that came in my rear dif setup i bought and i never thought to change them I guess that was a mistake. Am I the only one or maybe something else caused this?
With the OEM setup the bushings could be turned to dust and the diff still wouldn't come out of the car. Ive broken the aluminum housing before I suppose you could break both sides and the diff would come loose but the bushings are captured in a way the rear sub frame would have to be ripped apart before it would drop.
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Old 08-17-2016, 07:33 AM   #3
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With the OEM setup the bushings could be turned to dust and the diff still wouldn't come out of the car. Ive broken the aluminum housing before I suppose you could break both sides and the diff would come loose but the bushings are captured in a way the rear sub frame would have to be ripped apart before it would drop.
i have a ford setup from monster Miata but the bushings them selves literally just disappeared and then it shot metal sleeves up and the dif down lol. Dif never hit the ground of course because it was captured by the back of tech dif with two bolts but it still managed to flail around a little bit.

i just wanted to see all who has had the oem bushing fall apart like that.
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Old 08-17-2016, 12:12 PM   #4
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Haven't seen or heard of this...ever.
Sounds like yours was either not put together correctly or something was super janky. Definitely not common or even normal.
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Old 08-17-2016, 02:26 PM   #5
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The only way I could see the diff coming off the car is if you failed to put the retainer cups on and just put the nuts straight on to the bushing sleeve.
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Old 08-17-2016, 03:35 PM   #6
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Yep, user error or they're rusted through or broken
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Old 08-17-2016, 05:26 PM   #7
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Got any pictures of your setup so we can assess how the setup is different than OEM?

I'm not sure whats going on here but I think there could be some significant design flaws with this.

766DD6A6-89BB-4D22-A2C5-71D5A0073C81_zpsd60drkxk.jpg Photo by shortpersonbk | Photobucket

Last edited by bbundy; 08-17-2016 at 05:38 PM.
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Old 08-17-2016, 06:36 PM   #8
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The only way I could see the diff coming off the car is if you failed to put the retainer cups on and just put the nuts straight on to the bushing sleeve.
Retainer cups were on...both sides the clips were bent and the studs were snapped. Clearly they cannot hold the weight of the rear of the dif when a failure of the bushing happens lol.

Didnt notice the destroyed tabs till now. Kind of a bummer as this means the rear sub assembly needs to be removed and replaced.
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Got any pictures of your setup so we can assess how the setup is different than OEM?

I'm not sure whats going on here but I think there could be some significant design flaws with this.

766DD6A6-89BB-4D22-A2C5-71D5A0073C81_zpsd60drkxk.jpg Photo by shortpersonbk | Photobucket
Monster miata mounts very similar to how the oem setup is so i doubt it is a design flaw in the physical mount.
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Old 08-17-2016, 07:41 PM   #9
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*Edit just pulled subframe ...and looked around it looks like the retainer cups were not on or there would be a piece of hte broken plate between the bolt and whats left of the bushing.


Sucks i bought this all put together and just tossed it in without really looking at it to much.

So guys dont do..what i did.
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Old 08-17-2016, 08:06 PM   #10
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*Edit just pulled subframe ...and looked around it looks like the retainer cups were not on or there would be a piece of hte broken plate between the bolt and whats left of the bushing.


Sucks i bought this all put together and just tossed it in without really looking at it to much.

So guys dont do..what i did.
The picture I linked from your build thread shows the lower retainer parts of the mounts not installed. It would be totally relying on shear strength of rubber in the upper portion of the mount. Installed the way Mazda does it there is limited movement allowed before it bottoms out hard in compression of the rubber bonded on the lower retaining piece.
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Old 08-17-2016, 08:35 PM   #11
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The picture I linked from your build thread shows the lower retainer parts of the mounts not installed. It would be totally relying on shear strength of rubber in the upper portion of the mount. Installed the way Mazda does it there is limited movement allowed before it bottoms out hard in compression of the rubber bonded on the lower retaining piece.

That is not a design issue...that is a issue where they just were never put on. The whole assembly came from a running car and we just kinda shoved it in without paying much attention. It was pure install error...in the future i will have to make sure not to trust things as much just because they came from something that worked.

New retaining cups and bushings will be on the way by the end of the night just have to decide which ones i want.


Now that the issue is solved i can move onto my trunk mounted radiator.......inb4 many neg cats.
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Old 08-18-2016, 02:40 PM   #12
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Well I'm glad I guessed correctly. I learned from experience because I had a 280ZX that did the same thing because someone worked on the diff before owned the car and didn't put a retaining washer under the bushing. Diff hit the ground leaving a stop light one day. 16 year old me was completely confused at the time.
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Old 08-18-2016, 05:12 PM   #13
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Im surprised that the thin material and the baby bolts is enough to stop that bushing from doing that...


Sadly it looks like the mounts that hold the retaining clips are destroyed so i will need to have something welded up to fix that.
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