my 79 is wearing one of the tires drivers rear I looked and the ujoint caps are wearing into the housing.I did a little research and believe I need stub hubs but what other parts will I need? I assume I have to take the diff cover off and will need gskt, lube and limited slip additive bare minimum.If someone could tell me what all I need at the best scenario and worst and where to get the parts? I heard to try to use oem ,but some years have issues or aftermarket ? I came here for the right answers and thanks a head of time.

 

The part is called a differential side yoke. The inner end is likely worn off and all that metal is in your diff. Best is to remove the diff and inspect it. Clean-up and side yoke replacement along with snap rings is the very minimum. You may get it apart and find you need a complete diff rebuild.

 

someone said the posi unit causes this is that the case ? do I use oem or aftermarket stubs? where is the best and most economical place to buy these parts eBay they want 150.00 for posi clutches and springs and rock auto has for 70.00.

 

The posi does not cause the wear, the side yoke pushes inward due to it being the upper link in the rear suspension . The inner tip presses against the cross shaft and the yoke from the other side pushes on the cross shaft from the other side. While going straight, both side yokes and the cross shaft age going the same speed, so no friction or wear. When you turn a corner, one wheel goes faster than the other, so the stub turns against the cross shaft slightly. GM had issues in the late 70's with the tips of the side yokes not being hardened enough and ended up with wear like you are seeing. When you tear it down, you will likely find the inner end of the splined shaft is badly worn and mushroomed over. The posi clutches definitely wear also and will need to be checked. You might as well plan on replacing them and doing a proper rebuild because without shimming them properly, it is virtually impossible to set up the spider gear(pinion) backlash and get the right clearance for the side yoke to cross shaft clearance. If you are doing your own work and have the time, it's best to tear down, inspect and then order parts. the other option is to send your diff out for rebuild or get an exchange unit. Getting a used replacement may put you in the same position you are now. As far as who has the best side yokes and posi clutches, you could send a PM to Tracdogg2 and get his recommendation, he is also one of the best rebuilders.

 

Here is a shot of my rebuilt rearend showing the ends against the cross shaft. Before I had a lot of play. I'd plan on a full rebuild.

 

thanks for the info so far so I am looking at two stub hubs at least what about the bearings and seals just inspect and replace as needed?The car has less than 100k so I will inspect and replace only what's needed after careful inspection.I know I will need diff gasket gear oil and posi additive I am just trying to get a parts list together.What all else should I consider ?

 

there are different quality of side yokes out there. you want the ones with the hardened ends. cheap chinese parts may not be hardened.. spend good money for good parts, especially in this case.

 

where is the best place with best price I am sure someone has already been down this road and done the research?

 

I would rather use a rebuilt (tipped) side yoke than anything brand new from China...think Lonestar caliper

 

Is there any machining or measurements for bearing races etc that would need to be done on the differential housing itself or, is it just a remove and replace process?

 

Here is a pic of the differential from my '75. Major wear one C clip was missing. I am lucky it did not cause a wreck. I have installed a rebuilt differential.