68' rear noise, metal shavings

[greggome]

aside from the large expense of rebuilding a differential.how difficult is it getting it out of the car? it looks like a bear of a job!

 

[GTR1999]

Hi Gary,
I have a couple of questions. Why do they replace stub axles when they rebuild rearends? And do you use new or re-manufactured / rebuilt stub axles?

Hi Frank
Sorry for the delay, I just stopped back here.

Why do rebuilders replace axles? Well that depends on the rebuilder. I replace them if needed only. Here is some history on the 63-82 vette diffs. First there wasn't a real good one in the whole run. Every year has certain issues so the perfect diff is one that is correctly custom built. The mid to late 70's were the ones that had soft face axles. Somewhere around 1973 the mfg either stopped hardening the faces, GM didn't require or check it, or maybe a vendor change as made and this started - I really don't know other then they were soft, in the 10-30 Rc range. The cross shaft in the posi case, which the axle faces hit against are a 60Rc which is much harder. Thus the soft face axle were ground down, turning the gear oil into lapping compound, and if left too long the axle would grind into the seal and housing. I had diff's come in where they cut into the housing and then locked up, breaking the diff. So when I get in a diff I check the axles for hardness and wear. I have reused the 63-72 axles with over 100k miles on them. I have had in later C3's in with under 60k miles and the axles were worn down to the snap ring that holds them in place. I use Lone Star's rebuilt axles or Tom's axles depending on the build type. I stay away from "new" axles since I believe they are imported and the ones I did use were no good.

 

[GTR1999]

aside from the large expense of rebuilding a differential.how difficult is it getting it out of the car? it looks like a bear of a job!

Remove the tire tub, exhaust, spring- to cut the weight, strut rods, 1/2 shafts, support the diff using a jack or small trans jack, disconnect the driveshaft and front bracket, pop the cross member loose and drop the diff and cross member as one. Typically 3 hours or so depending on how well the parts come apart.