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A quick update to this project. After about 5000 miles on the new diff, it's whining and clunking. Not as bad as the old one, but it seems to be getting there. I may have to open this one up and re-shim it, though I am loathe to pull the diff on jackstands again.
If the backlash is opening up as we drive on these diffs, it must be either gear wear (unlikely), bearing wear (unlikely), or case distortion.
Used to own a 2007 Sky (redlines were not a thing back then) with an LSD. Worked great for that gutless engine. Wish I had kept the diff when an 18 year old ran a red-light and took the whole front end of the car with him.
I spent about 6 hours today pulling the diff, re-shimming, and reinstalling it. I didn't think to measure the backlash before I tore it apart, but I set it just under the factory spec (assuming it's just going to keep opening up, plus the only shims I had ended up being a little under spec). The clunks are now gone again, and the highway whine is mostly gone. I wonder how long this will last till it opens up again or just splits open and dumps its guts!
I did not read the entire thread and I am sorry if you already posted this but do you mind posting the parts you used and any possible directions you have? Interested to try this and the V1 diff brace. If you got all the diff parts happy, the brace should prevent any further case distortion and the diff should stay quite for X amount of weeks/months/years...
The key parts are the diff bearing puller tool (details earlier in this thread), plus you'll want an assortment of shims or the ability to make your own shims. Other than that, you should probably be able to find resources on pulling the diff out of the car, then follow the link I posted for the Saturn Sky forum for details on re-shimming.
Who makes the V1 diff brace? I was toying with the idea of building my own bracing for this last re-shim, but didn't end up doing so because at this point it feels like it would be polishing a turd.
Another update:
She clunks again, and whines like crazy on the highway. It's loud enough that my passengers complain! It also grinds while turning sharp corners.
I think I'm going to try a 3rd or 4th gen diff to see if it's any better, and swap in my 3.91s and LSD. Does anyone know if I can swap the complete carrier/ring and install my pinion in the new-style pinion cartridge?
I would say it works, cuz u have also abilities and skill to check the clearance everywhere, but if u swap the Gen 2/3 inlet cover on pinion to a Gen 4 case u may loose the gain of this new style cover, if there is any btw...
I will also try to make some changes on mine next time to get rid of the whine in regards to play on shoulder bearings, I also swap to Mark's brace and my new axle shafts, hope to find a solution here about the whine...
At the moment i'm on a air cooling duct from diff brace:
Greetz
Ron
Last edited by Choppy_Idle; 09-01-2018 at 12:43 PM.
I had thought to swap the old pinion shaft into the new-style cartridge, but swapping the whole cartridge could perhaps be a better (or, at least, much easier) solution. I'm having a hard time imagining how the cartridge design could influence case distortion, but I suppose GM must have updated the design for a good reason.
The cooling ducts are an interesting idea. Hopefully you took some baseline temperatures so you can gauge their effectiveness. I wonder a few things: does the underside of the car get enough relative airflow to utilize air scoops? I suspect you might be better off with the rear scoop only, since the first scoop may rob the airflow to the second scoop (which feeds the part of the case with the highest heat convection potential - the cooling fins at the back). Would the loss of cooling capacity when the car is not moving reduce the overall heat transfer from the diff? (this might change with your use case - high speed autobahn runs, track sessions followed by cooling in the paddock, etc). Might be worth a new thread to discuss.
05-29-2018, 12:10 AM
