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Driver side rear differential bushing torn, what's my best option?

MICHPP2

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I've been working on my car now that it's warm enough to be outside for more than 5 minutes, and while installing the Lethal Extreme Through Bolt kit on stock bushings (hoping to prevent damage to the stock bushings) I noticed a nice tear in the driver side rear differential bushing.

image0.jpeg


At this point, I'm trying to figure out what my best option will be for a mainly street car, with some upcoming track time. I'm trying to maintain closer to stock NVH levels.

I found a Superpro poly/hybrid bushing replacement (TRC4758) which looks enticing, but I've read conflicting things about solid poly bushings in this spot. I'm definitely not doing solid aluminum.

Image_69e6a2db-5021-4b68-bdde-1dc27ffc4910_1024x1024@2x.jpg


Another poly option is the lockout puck-style inserts. I've been reading that the Steeda red kit is the quietest, but the question is are they safe to run over a torn stock bushing?

I'm also thinking about getting a new subframe crossmember from Ford to keep the stock levels of NVH, but upgrading the hardware with sleeves in the rear bushings so there's no slop.

What are your thoughts?
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MICHPP2

MICHPP2

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I'm going to go with the Superpro bushings. I'll let everyone know how it goes if there's any interest.
 

spaz mk will

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I’m am looking at the superpro also while I’m doing 4.09s in the future. Did you use the lethal differential bolt kit with those? Curious if that combination works together and in what way or if the included bolts should be used. Did you use the Lethal sleeves or not?
 

KellTrac

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Unless they drastically improved upon them from the bolts that came with my SuperPro bushings (2016/17 ish) DO NOT use the included fasteners. They sent me just some super basic 8.8 Graded bolts that retained the shear path force directly to the threaded part of the fastener which is a massive " no-no".
 

spaz mk will

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Thanks @KellTrac. Maybe the more accurate question is: Do the superpro bushings have the same I.D. as stock bushings? My guess is yes, and that would mean a kit like Lethal’s with the added sleeves would still be needed to remove the slop/add strength.
 

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krishelnino

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I'm going to go with the Superpro bushings. I'll let everyone know how it goes if there's any interest.
Any update on this ? doing a diff rebuild with 4.09 gears soon and looking at diff bushing/lockout upgrade at the same time
 

Bahndvr

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A shame SuperPro doesn't ship to APO.
 
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MICHPP2

MICHPP2

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Did you ever install the bushings? I've also got a torn diff bushing and I'm contemplating my options.
I ended up getting a GT350 subframe from a nearby Ford dealer and replacing the entire subframe myself, the bright side is the bushings are more reinforced on the body to subframe mounts (no voids in the rubber-solid all the way around) and the driver side rear diff bushing (more rubber around it).

this increased some diff noise in the cabin slightly but it’s not bad, probably a lot less noisy than poly diff bushings would’ve been.
 

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andrewtac

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I've got the superpro with Kelly's big Bertha bolts. As a matter a fact, right after I consulted him on this they (the super pros) showed up on his website; which I see as a rather positive endorsement. I went from the bmr aluminum ones, sounded like a jet engine from the whine before, now no more noise. 1.4 60' a10 9 sec car, so far no issues. Will be pushing the car harder next year. If you get them search my posts on them I included some install lessons learned.
 

japont4

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You can also get the differential bushing inserts from Steeda and you probably wouldn't need to replace the stock bushings.
https://www.steeda.com/steeda-s550-...t-system-urethane-2015-ecoboost-555-4443.html
I was considering going this route. I technically just have hairline cracks on them right now. But I think I ended up snatching some Whiteline bushings that are softer than Steeda's bushing inserts. (I say I think because from what I've read, these have been discontinued)

I don't wanna just do the inserts since I'm technically not fixing the damaged bushing but if everything else fails. I'll give it a try. My car is a DD and it doesn't get used for track days anymore so NVH is my biggest concern right now.
 

GTP

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Mine were not torn, but I added Steeda red pucks and aluminum gap spacer sleeves as a preventive measure. I could not lower my cradle enough to get the front pucks installed. I did not notice any difference in diff whine whatsoever (and I was hoping for some, lol, #BecauseRaceCar).

To the OP, your photo looks like the tear is not that bad. If it was me, I would add the pucks and call it good.
 

hot rod

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Unless they drastically improved upon them from the bolts that came with my SuperPro bushings (2016/17 ish) DO NOT use the included fasteners. They sent me just some super basic 8.8 Graded bolts that retained the shear path force directly to the threaded part of the fastener which is a massive " no-no".
Finally they updated to 12.9 hardware.
But what i don't understand is why they have the same gap in the bolt location like the OEM ones. Is it for NVH reasons or is it factory tolerances of the subframe?
you can put sleeves in it.

IMG_6345.jpeg
IMG_6347.jpeg
 

WD Pro

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Personally I think it’s done to allow for manufacturing tolerances and quick assembly.

It takes greater care and more time to fit the bolts when their movement / wiggle room is restricted by the sleeves :like:

WD :like:
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