Well, I went out to change my spider gears this morning and got a surprise when I pulled the diff cover. Found a posi in there instead of a peg-legger! It's totally shot, if you jack up one side and leave the trans in neutral you can twirl the wheel with your finger. I never figured there was a posi in there, it's always spun the right rear in rain and snow. Anybody rebuilt one of these before? I looked in my FSM and it doesn't seem like rocket science, anybody have any tips or tricks?

 

How can you tell by looking at it if it is limited slip?

 

The open diff is a one piece casting with two spider gears. The LSD/posi unit is two pieces and has 4 spider gears. If your rear has a tag on it still it will say 3 54 LS on it somewhere if you have 3.54's and a posi. I'm so I just assumed that because it was acting like a peg legger that it was one. I never even looked at the tag until after I got the cover off and went . Then I picked the tag up and read it.

 

Rebuilding a Powerlock is as simple as unbolting the case halves, and simple R and R of the insides. If your spiders are shot there is a kit available (complete inner kit, I believe was the listing) that contains everything but the case. The FSM calls for a case spreader to ease the reassembly process, but I have always had good luck using longer bolts to pull the caps in evenly, then using the factory bolts for final tightening.

 

Do you think after 220k it will be hard to get the diff in and out? I'd have thought the beaings would be worn in pretty good by then. The spiders look pretty good but there's a lot of slack between the diff case and the cross shaft. You can turn the driveshaft about 1/8 of a turn before the axle shafts turn. Is this due to the cross shaft being worn out or the fact that the clutch packs are basically gone? I can see that if the packs were worn badly the cross shaft would be able to turn farther than normal, but has the cross shaft been damaged from running like this for who knows how long? I gotta try to return my spider kit and order parts on Monday, it would be nice if all I needed was new clutch packs.

 

I would say that the slack is probably due to excessive backlash in the ring and pinion due to bearing wear. In a high milage Dana the carrier will be looser due to bearing wear, but you don't want to put it back together this way. Properly set up it will fit tightly. Check your pinion for in-and-out play also.

 

R&P seem OK, when I had the cover off yesterday all the slack seemed to be inside the diff itself. The rear is quiet when driving, no leaks from the pinion seal.

 

Wanna
If your bearings were so bad as to have axial looseness, the ring and pinion would have failed long ago. Increased Back lash in the diff assembly is caused by the combined looseness (wear) of all parts in the diff.
Remove your carrier and rotate the pinion slowly, feel for roughness or binding in the rotation. If smooth leave it alone. Replace the clutch packs (mark the carrier halves for alignment later) and any other worn carrier parts and put it back together.
DO NOT change the back lash in the gear set (ring and pinion). The back lash is built into the gearset (machined in) and when set up for the first time it is set to certain values to achieve a proper match. If you were to move the ring gear to the right /left or the pinion in/out you will loose the match and potentialy enhance ring and pinion failure.
The only bearings you may want tp play with are the carrier bearings. although I caution you the due to the fact that tappered roller bearing come in a wide range of cup and cone width and they are not selective ( on a precision tappered roller bearing the width can vary up to .020 each) I dont have the specs on a non precision bearings that are used in diff units.
So that being said, Its no big deal to pull the carrier and replace the internals but when you start playintg with the external parts be cautious .
PM me if you have more Q's

 

Yeah, that's what I was hoping to do, just pull the guts out of the diff and replace with new. I figure since the rest of the rear is working OK I would be foolish to mess with it.