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More reliable front diffs?

836 Views 10 Replies 4 Participants Last post by  chuckybob
So a few hours and a few hundred miles after buying my van, heard a LOUD THUMP THUMP THUMP THUMP on the highway. Pulled off. Wheels looked fine, some play in the CV so I towed it home from there.

After inspection, there's A LOT of play on the passenger side CV where it meets the front diff, and play matches the sound, so I'm thinking the needle bearing in the front diff blew out. This seems to be a very common failure point for AWD.

Front end rebuild is in order. While I'm pulling everything out, is there either a heavy duty rebuild kit or a front diff swap that improves reliability?
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A pic of the beginning. Side by side shiny aluminum vs dirty cast. Had to change front yolk, shifting diaphragm was removed, new seals paint few other parts then it bolted in place.
Did changing the front yoke require resetting preload?
Tungtide, thanks for the pics. They were a huge help in understanding the swap. After agonizing over the potential swap and reviewing threads here and on the S10 forums, looks like:
  • "Simple" swap is only possible for GT4 RPO option (3.73:1 differential)
  • Front driveshaft yolk must be swapped to Astro/Safari/Bravada model
  • Vacuum diaphragm must be removed from s10 differential
  • Axle tube must be swapped to Astro/Safari/Bravada model - This will remove front locker option but improves reliability
  • Differential mount from Astro/Safari/Bravada model must be kept, or will cause premature wear due to incorrect mounting angle
  • Worn engine mounts may prevent install, clearance with oil pan may be an issue
  • Second-gen S10 differential case with ZR2 4x4 Manual option is always cast iron, others vary

  • Bushing from Astro/Safari/Bravada model must be maintained?
  • Compatible 3.73 iron diff case available on other models/years? Would be great to just swap in an LSD. Looks like maybe Envoy? Front differential
  • Am I missing anything here? What's going to bite my butt if I attempt this?
  • Is there anyone here with hands-on experience with this swap or maybe a build thread that I missed?
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