I have a 3.55 LSD 8.8" rear diff on my 2004 (04-08) Ford F150. Unbelievably the 10 bolts which hold the Ring Pinion in place have loosened (one having sheared off, one fallen out and a handful bent whilst still fully threaded)! I'm hoping the only serious damage that was sustained was a damaged diff cover and that everything will keep running. So, I've ordered some new bolts for the ring pinion, but need to know the torque values for these? Also, what should the toque be for the bolts holding the diff cover in place?

 

https://lib.americanmuscle.com/files...rs-install.pdf

 

For a bolt that size, 75-80 ft/lb would be about right. I'd use Locktite as well.

 

Did you take it out at any point? If not, that's scary as hell. As fast as it spins at highway speeds it would disintegrate.

 

Could you give more detail? Did you buy it with the cover off and the bolts falling out? Or were you driving it like that?

Looks like somebody had it apart and didn't get it assembled right. They either didn't torque the ring gear bolts to 77 ft-lbs like the service manual says, or they had the ring gear off and didn't get it seated fully. Weird problem. You'll want to be sure the ring gear is seated and retorque all of the bolts. Might want to check a bunch of other things if you bought it already falling apart.

The service manual says 33 ft-lbs for the cover bolts.

 

Thanks for the replies all. I've owned the truck for four years, with only one previous owner. I was driving approx 30mph, when I heard a small 'bump' from the rear end. Drove a further 6 miles to get home, during which the ABS light came on as well as the spanner with an ECU P2106 [Throttle Actuator Control System - Forced Limited Power] code showing up. On the drive I found the diff cover punctured in two places and barely any oil left inside. There's no evidence that it has ever been worked on by the previous owner, but who knows?

 

did it fix the problem, Im having the exact same issue.