8.8 IRS Differential Bushings?

[Crawleyscobra]

I currently have the 8.8 IRS Differential with the solid mounts on the front (drive shaft side) and back (diff cover).

Has anyone switched to poly on the front AND back. I guess my main question is, "Are poly bushings available for the rear (diff cover) mount?"

I have the infamous drive train clunk and am going to have a shop go through my diff. As part of the work I would like to install poly bushings to soften the diff inputs to the frame.

[Jacob McCrea]

Based on your build date I assume you have the old-style, T-bird-based IRS unit (the MN-12 differential, as it is sometimes called). I've never seen any kind of bushing at the IRS "cover mount," whether with the factory cover or the various aftermarket covers. I've only seen covers that bolt directly to the IRS cage/subframe, as a "hard mount," with nothing there to dampen vibration or allow flex - at least on the FFRs. I have no idea how the T-Birds, Mustangs and Lincolns get away with bushings up front without cracking the rear mount.

I guess you could re-fabricate the diff cover or the rear frame mount to employ a bushing or something else to let the diff move a little and absorb vibration. I have seen a rear mount (Hank L's coupe) that bolted in and out, and I suppose you could easily sandwich a bushing or vibration-dampening material between the frame and a re-fabricated, removable rear mount.

[Crawleyscobra]

Jacob, thanks for the reply. It looks like I am going to fab something up. I have spend quite some time just Google searching and have not come across anything.

[Jacob McCrea]

I'd probably buy one of these and graft an IRS mount with integrated bushings onto it. It may (or may not) be easier to do that than re-fabricate the mount. Although I and probably many others would love a removable mount back there, bushings or no bushings. And if you want an extra stock cover to experiment with, I have 1 or 2 around that you can have.

https://www.ruffstuffspecialties.com/catalog/88DCOV.html