Does this appear too worn to use?

 

Kind of hard to tell because the yellow pattern grease is smudged but on some teeth the pattern looks a bit suspect. Was it quiet when you took it out of service? If so, then I would run it. Old gears are sometimes better than new ones. Gary (GTR999) would be the best person to ask.

 

Gary seems the most knowledgeable here on the forum when evaluating gears.
I believe the gears look good and would not be afraid to re-use them if they were not problematic when you removed them. But, an 'in hand' evaluation may show wear that pictures don't.
Not having all of the professional equipment to install and setup gears, I found it is extremely important to document the shim thickness on both sided and on the pinion when disassembling gear sets. If you are going to reinstall those gears in the same housing or even in a different housing, it makes it a lot easier and faster to set them up.

 

Thanks guys......This diff must have been cut out of a wreck because the camber rods were torched off and mounting and snubber brackets were on it so no clue if it was quiet. Very clean inside though and may have some miles because it turns pretty freely. BL is .007. I did run patterns but when i saw this wear I wondered if this is normal.....it is not gritty, it's smooth but has a wear look to it. It is a GM gear.

Gary, would appreciate your thoughts!

Thank you!
Brian

 

How much in/out play on those axles?

JIM

 

They felt like they were pretty good but did not measure.....will check tonight.

 

Since it's a used diff you also need to closely inspect the posi case for hairline cracks.

 

I can't tell anything from your pictures. You have a used gear set.

If I was checking that diff the first thing I would do is see if it's been worked on before. I know where to look to see if it's been touched.

If it's original I would then check the lash, rotation, and pattern. Your paste make up is not good enough to show a sharp pattern. What I see appears to be deep on the drive, but again it is a used gear set. I spin them and listen to the mesh. There should be no clunking.

Now if it has been worked on, all bets are off. Not saying they're bad but a lot of people working on these diff's are clueless and often create issues. So, in that case I would still look at getting a better pattern and listen to the gears.

I have seen used gears with similar patterns that were still good. Typically, those diffs were shipped to me and I was able to discuss the history of the car with the owner to determine if they were ever touched before.

Axle endplay can be anywhere with original C3 diffs. If the axles are original the most likely need to be treated or replaced, depending on the condition of them. I see guys say 040" is ok, it isn't. It is typical of a car with 50k miles and affects the handling of the IRS. You can band aid it with a 6-link but that a lot of money that isn't needed for a street car. If the diff was correctly rebuilt in the past then the axles should be under 008" endplay and no less than 005". I would be surprised if that diff has endplay under 025" but you never know. New axles alone won't change it enough. If rebuilt or new axles are used you better do your research on them, if I told what I know you would surprised and all the vendors would complain, so I just concentrate on the diff's I build these days.

Good luck.

 

Thank you Gary,
driver side is .014 and pass is .009.

it has been worked on. bL is .007. Gears run nice and smoothly but doesn’t seem too have much preload resistance.

here’s a better pattern. Should I try to replicate this when putting back together with new bearings and seals or try for a better match? It’s clean inside. Posi case appears to be fine. It’s a 76 or 77 as far as I can tell.




Really appreciate the help!!!

 

Those patterns look a lot better to me. The teeth look clean, no chips on edges. If as Gary said you don’t hear or feel any clunking as the teeth move into contact with each other then I would think everything is good to reuse. BL of .007 is pretty impressive on a used set of gears so someone may have been inside it before to rebuild the limited slip or something.

 

Gary,

Who sells the best rebuild kits? I see Bairs has Timkens in theirs. And correct shims?

Thanks again

 

If I get into vendors and my opinions of some, plus what I have seen for a long time, I will just get in trouble. So, I rarely mention any vendors anymore. I will say I do not buy my differential parts from any Corvette vendor. I do buy some specific vette parts from Bair's and always liked them, so I don't want it to seem like I am referring to them, I am not.