Hey guys,

I'm trying to fix a mild grinding and loud whine in my rear end. Currently the differential is completely disassembled. Everything looked okay, including pinion depth, back lash, and wear pattern. HOWEVER, the damn center section was a BEAR to get out. I probably pounded on a crow bar for 20 minutes trying to pry that sucker out of there. Is this normal?? It seems WAY too tight in there. If I try adjusting that fit so it's more loose, won't that affect my backlash? I could be wrong, but it's my understanding that this center section should not be that hard to get out. Is it possible to add/remove shims to make it slide in there a little easier? (Without drastically changing my backlash.)

I would think that having that SO tight, it would compress my bearings and make them not function as well. And possibly cause excessive noise.

Any advice you guys could give would be greatly appreciated!!

 

Not normal, could burn up your bearings from excess preload. You can remove a little shim from the passenger side. Don't take any off the driver's as that will increase the backlash. I've heard old heavy duty applications used monster carrier preload like .010-.015" (!) requiring case spreaders. But modern apps use more like .003". And preload can go to zero once that rear end breaks in and the case spreads a little.

Since I've only set up used rear ends, I figure any case settling that's going to take place already has, so I just add a thou or 2 past zero strictly to keep the carrier from moving laterally and affecting backlash.

My favorite trick for popping out the carrier: put a closed end wrench on one of the ring gear bolts. Then put a ratchet on the pinion nut and turn so wrench goes towards the top. Put a folded rag between the wrench and the housing for protection. Then turn on the ratchet and it will spit the posi right out.

Once I learned this trick, I've never used a prybar again. Much easier to control, especially if you're working alone under a car.

 

Okay...I have an update.

I think it was set up a little too tight and that's why I was getting the grind/whine. Here's what I found...

Original setup (too tight)

.247 in shims on the driver's side
.238 in shims on the passenger side.
This made .006-.008 backlash.

1st attempt to fix...

.238 in shims on the driver's side
.238 in shims on the passenger side
This made .015 - .016 backlash.
(It seemed too loose.)

2nd attempt to fix...

.241 in shims on the driver's side
.238 in shims on the passenger side
This made .011 - .012 backlash.
(Should I leave it??)

I have Richmond 3.73's and they call for .008 backlash. Grr.

I still have it all apart, but I'm not sure if I'm going to attempt trying it again. The adjustments I made were all on the driver's side. Should they have been made on the passenger side?

Thanks again!

 

If you remove a shim from the passenger side, this will also change the backlash. If someone wants to reduce the bearing preload without effecting backlash, you should remove equal amounts of shim from each side.

Also, it isn't the wisest idea to gauge how much preload is on your bearing merely by how "hard" it was to remove the differential from the carrier. The proper way to check bearing preload to the use of an inche pound wrench. Place the inche pound wrench on the pinion flange and observe the torque to rotate.

 

i agree!