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8.8 rear with pretension bolts

I have an aftermarket diff cover with pretension bolts for the carrier bearings. After removing to cover to pull the axles, I went about 30 miles before I got a scratching noise from my rear end. I never touched the pretension bolts, but I'm thinking that the discarded gasket in favor of Permatex for the rear cover seal may have the bolts tighter than they were. Hence the grind.

1. Did I screw up?
2. How bad?

Any help on how much torque to apply when I reset the bolts would be appreciated. I purchased my '05 GT with this mod already on it.

Thanks.

Not sure of brand .... but here's this.

http://www.americanmuscle.com/frpp-88-diff-cover.html

https://themustangsource.com/newrepl...reply&t=531644

Quote:

AXLE GIRDLE INSTALLATION INSTRUCTIONS:
STEP 1: Remove rear production cover.
STEP 2: Check all internal components for visible defects and repair/replace at this time.
STEP 3: Clean axle housing. Do not use silicone on gasket.
STEP 4: Install the girdle with the supplied gasket, bolts and washers. Make sure the load bolts are backed out sufficiently so they will not contact the differential bearing caps while installing the girdle.
STEP 5: Torque the girdle to the axle housing bolts to 20-25 ft./lbs.
STEP 6: Tighten the two load bolts until they make contact with the differential bearing caps.
STEP 7: Torque the load bolts to 5-10 ft./lbs. Excessive torque can damage the differential bearings! Torque the jam nuts to 25-30 ft./lbs.
STEP 8: Remove factory fill plug, fill rear axle with recommended lube from the upper hole in the girdle until fluid runs out of the factory fill hole in the side of the housing casting. Re-install plugs.

As a rule of thumb I would always recheck torque specs on those bolts, especially if you made any changes in the pumpkin or axles.

On a side note, post#420 lol, guess scotch will have to do!

Any time you remove a gasket in favor of RTV you should make sure clearance isn't an issue as in some cases the gasket thickness is included in dimension clearance.

Thanks so much for the help. The procedure is exactly what I was looking for. Unfortunately, the damage is done. I'll be taking the car to Pro-Dyno on Friday to go through the rear end. Live and learn. This one is going to be a little more expensive than I care to admit. I believe the extra pressure on the carrier bearings has eaten up everything in my rear end.

Any thought on whether the limited slip would survive all the debris? I'm thinking that all of the bearings and the ring and pinion will have to go.

Time to change the gears too?? Maybe some 373's?

Not planning a gear change. I'm already running 4.10's with a 7200rpm redline. Stock tranny nets me 102mph at 7000rpm in 3rd. I'm planning to stay with the 4.10's due to the extra room I have on the top end.

A lot of parts in a diff are hardened so they may stand up to some debris. Guess you won't know till it's stripped down and inspected. The trac-loc may survive the best if the clutches were tight and didn't get debris jammed between them. Pull the axles right out and make sure the axle tubes are cleaned as debris can hide there. Good Luck.

Thanks. I'm hoping for the best news possible. She goes under the knife next week. I'll update the thread when I get the prognosis from Pro-Dyno.

I really do appreciate all the expertise on the forum.

The verdict is IN - maybe

I have my car back, and as I suspected, the carrier bearings were trash. They came out in so many pieces they couldn't count them. The rest of the rear end looks good and the contact area of the rear gear checked out. Work was done by Pro-Dyno just south of Charlotte, NC.

I am getting a whine out of the rear end. IMO, this is due to reusing the ring and pinion. They never go back in exactly how they came out. The nasty grinding noise of a failing bearing is a thing of the past.

I'm hitting VIR in early September, so we'll see if a couple of days of very hard use seats the gears a little better. It may expose another weakness in the system, which is always a concern at 145 mph.

I'll feel a lot better when we all come home in one piece.

here's hoping it will never have to come apart again

I'll try to upload a picture. I guess I should be able to figure out how. Please laugh amongst yourselves if this doesn't work.

And you always have to check out the backside.

I like that black over that green ;)
.... reminds me almost of my old '69 Dart Swinger that was almost same green with a painted (oem paint, not vynil) black top and I always liked it.