Rear Diff Cover Loose Bolts

[pastorwug]

Now it has happened a second time, the rear diff bolts have come loose enough that the gear oil starts leaking. Happened for the first time up in the mountains of Big Bear when a friend noticed a puddle of gear oil under my rear diff. Drove to a local repair shop and they said every bolt was just hand tight. Cleaned everything up and used good RTV, new gear oil and 12 months later I found the cover bolts just hand tight again, slow leak.
Anyone know why this is happening?
Performance Ford Rear Diff Cover.
Used RTV a year ago.
I never use the pumpkin to raise the truck rear with a floor jack.
Should I use Locktite this time?

Thanks for any help you can offer.

 

[Jakenbake]

What torque did you install the bolts at?

When I have mine in at say 20 or 25ft*lbs they would work loose. I think I have them at 30 or 33 ft*lbs with orange loctite and they have not worked loose.

My theory is that the stiff ford performance cover does not conform to the housing very well and allows the bolts to lose tension where as a softer/less stiff oem cover would conform to the diff housing and allow for a better engagement.

 

[pastorwug]

Several YouTube installs of the Ford Perf diff cover suggest blue loctite - I'll use this tomorrow when I re-do the rear diff.

 

[pastorwug]

Lube locker, RTV, or paper gasket?

 

[GCATX]

I don't know why it happens, but it happens on afermarket thick covers. Use some locktite.

 

[JohnyPython]

Just brainstorming here:

Did you tighten in a criss/cross pattern?

Blue loctite could solve this

Hopefully the threads aren’t pulled - the bolds should be a good fit in the tapped holes

 

[RPG9]

I would be careful with that hardware as those are not the highest quality bolts included with the cover. I swapped mine to Grade 8.

Highly recommend tightening in a star pattern as @JohnyPython noted. Loctite will not hurt.

 

[Gen1TillDeath]

RPG9 is exactly right. The hardware that comes with the ford performance cover is garbage. And the stock bolts are barely long enough since the performance cover is thicker. I got grade 8 bolts aswell from Home Depot when I installed mine. 3,400 miles, and no leaks.

 

[weimer]

Blue loctite, lube locker gasket and stock or upgraded bolts as stated above.

 

[Space Ghost]

I got another oem ford gasket, reused the stock bolts torque'd to oem spec and have been good since. Didnt put any locktite on mine, since when i pulled mine out i didnt see any residue on them, but was debating blue locktite.