Rebuilding a Rear Differential

[338Shooter]

So I'm going to build a diff for my truck. It is a GM 9.5" 14 bolt sf. I really want to do it myself, but I don't want climb aboard the fail boat either. I know it is critical to get the pinion depth correct and the backlash on the gears set properly. Neither look overly complicated, but I don't know. I know one way to set the pinion depth is to hone out the old bearing and use it to mock up the pinion. Once you get the right contact pattern you have the new bearing pressed on with the correct shims. I'll have a mechanic press on the bearings for me.

What I want to know is what it would cost to have a mechanic put it all together. I have no doubt that I can do it my self, but if it's relatively inexpensive to have it done I will consider that. I'm talking about bringing in the gear set, the locker, the hub to hub rear end, and a master rebuild kit to someone and then picking up a ready to roll unit. What kind of labor costs?

 

[PUMPKIN]

they make a spacer that takes place of the crush sleeve, and eliminates all the guess work with the pinion.

 

[338Shooter]

Wouldn't you still have to shim the pinion to set the depth properly?

 

[Super Dave]

Dustin,

I believe the idea of the shim is to take up the freeplay to a specific amount. I am pretty sure they come as a pack, with varying thicknesses... but I could be wrong. That's the way the endplay for the tapered bearings that face each other in a Harley lower end are set up. Got a dial indicator?

.

 

[338Shooter]

It is my understanding that the shims on the pinion are to set the depth the pinion contacts the ring gear. Once it is all together you spin the gear with some contact paint and look at the marks on the ring gear from the pinion. If it is not right, you add or remove shim from the pinion.

I will get a magnetic dial indicator to adjust backlash on the gears.

This process seems a little more difficult to find info on because it is not something that is done often and many DIYers don't tackle it. If I decide to do it, I'll probably do a write up with lots of pics.

 

[dieseltech09]

If you are just changing the ring and pinion just put it back together the way it came apart.

 

[338Shooter]

I'm planning on a complete rebuild with a locker.

 

[338Shooter]

And if I can do the back, I'll be doing the front as well. The T-case isn't going to like the 4.10s out back with 3.42s up front.

 

[dieseltech09]

If you want you can borrow my books from tech school. One of them has a step by step on setting up a diff. Ill have to dig them out of storage but Im pretty sure I know where they are

 

[338Shooter]

That would be awesome man. I'd really appreciate that. Can you tell me the book time do this with the rear out of the truck and the parts in hand?