Hey all, looking to rebuild my rear axle on my '94 F-150. It has excessive backlash when shifting from reverse to drive, or vice versa, and a bit more when moving from a stop. I have everything that I need to rebuild it, which includes bearings, seals, posi clutches, differential carrier shim kit, and now a new ring and pinion. The only things I am not replacing are the axles and the differential carrier.
What I am in need of now are the torque specs for the nut on the pinion gear, the bolts that hold the ring gear to the carrier, and any other specs needed. Any help would be appreciated.

 

Subscribed - I just bought a used 8.8" rear end to get a limited slip and I plan on rebuilding the entire thing just like you - be sure to let us know how it goes.

 

I just recently did the same rebuild your describing. Only I just did bearings and seals (eventually regearing) but I sinched down the bolts with an impact gradually around and getting tighter. I put on the green loctight. I did it by feel and it's good. No deflection with anything. I didn't use a torque wrench but I'd say it was 90 ft. Lbs. Good luck! Make sure to clean tubes out and use lube on all bearings and seals during assembly. I bought some synthetic royal purple.

 

Just tighten the pinion nut a fuz and call it good lol jk

 

I found this earlier. Ford 8.8 Ring Gear & Pinion Sets | Ford 8.8 Rear End Parts & Application Information - Drivetrain
It gave me the torque specs of the nuts and bolts inside the differential. Found a video on how to do the crush sleeve preload, which looks like I need a bigger wrench.
Also, anyone know where I can get some good limited slip supplement or of the Castrol gear oil with the supplement in it is good enough?

 

The royal purple synthetic fluid has the limited slip additive in it already. I would use that but if you didn't, go to a Ford dealership and they can hook you up with correct Motorcraft fluids and additives (exact factory stuff)

 

The pinion nut sets the preload on the pinion bearings. If a crush sleeve is used the pinion nut is tightened enough to crush the sleeve and correctly preload the pinion bearings. If a correct length solid spacer is used instead of a crush sleeve then there is a torque spec for the pinion nut that will correctly preload the pinion bearings.


Either way, the pinion bearing preload needs to be correct. It's done by measuring the rotating torque (inch pounds) at the pinion nut before the carrier is installed. I don't have the spec off hand for an 8.8" rear axle.

 

The carrier pin should be between 15-22 ft lbs.-use loctite on it you don't want it backing out

I think the preload on the pinion was around 20 or so inch pounds,I used a beam style torque wrench.

The carrier cap bolts was somewhere around 80 ft. lbs.

and a better way to set up the limited slip than factory is

GEAR| S..F..S..S..F..S..F..shim

S=Steel F=Friction

Soak them in friction modifier for around 30 minutes before you install them

The S-spring can be a real pain to get back in to don't let it pop out and hit ya in the face

 

Update... finally. Started taking the differential apart today. Found that someone else already tore into it before me and fixed something. Looked like the pinion crush sleeve was pre-loaded correctly. When I pulled the differential carrier out though, it almost fell out after taking off the first main cap.
After getting the second cap off, and not dropping the carrier, I looked to find that there were no shims between the races and axle. What's more the spider gears in the middle were chipped a lot. There were chunks missing along the back of the gears and had what looked to be galling (spelling) on the teeth.
But the good news is that the ring and pinion are in great shape and can be reused. Bad news is that I have to wait on getting the spider gears seeing that no local auto parts store had any for posi differential cases and that Summit wants an arm and a leg for their stuff. $135 for gears, from Summit, that would be there at the end of the month or ~$235 for gears that would be there next week.

 

That sucks. I rebuilt mine last fall. I replaced the axles too. They had them pretty cheap at bronco graveyard. When I did the s spring for the limited slip I did it like I seen on Hot rod tv and did it like they did. The trick work really good. I used to rebuild rear ends at a ford dealership back in the 90's. I tightened the main pinion nut by feel. Used 2 fingers and my thumb to turn in if i put in new bearings and just one finger and thumb to turn it for used bearings. Never had one fail. I did a bunch of 9 inch rears that way too.

 

8.8 Trac-Lok Gear Kit-Broncograveyard.com