Howdy,
Sorry if this is a noob question, but I just had my 9-bolt ('88 GTA) rebuilt by a local reputable shop. However, they took a year and a half (dropped it off April 2024) and for the entire time I got one "reason" after another as to why it wasn't ready. Long story short, I told them a week ago that I had to pick it up whether it was done or not and 2 days later they said "hey, it's done, pay us". Which I did. As soon as I got it home I pulled the cover and ran the axles around a few times and took some pics of the pattern. I'm hoping someone here can tell me if the pattern is "crap", "good enough for the street", "amazing - how did they do that" or... This will be a stock-rebuild drivetrain, L98 with a very mild cam upgrade, street driven 99.9% of the time.
I have another shop about 4 hours away that only does diffs, has a great rep and when I talked to them, they said they had rebuilt these before (actually knew what a 9-bolt was, as opposed to the shop I just got it back from) but it had been a few years. Still, thinking of taking it to them to check it out and make sure the 1st shop did a good job.
I'm attaching pics I took of the pattern on both sides of the gear and I'm hoping to get some feedback here.

TIA and apologies if the pics are too big!

Mark

 

Pinion depth is way off it looks like. Did it howl when you drove it home? Unfortunately, if that has any miles on it, it may make noise even when properly shimmed.
How To Create & Read Ring Gear Patterns https://share.google/8BP1L8mWHoAwlophI

 

A year and a half for a few hr job and the pattern looks like that? I'd definitely have it fixed right

 

Thanks for the link, very interesting! Fortunately (or not), my GTA is still in the "some assembly required" stage - no diff, no engine, no trans. My bank account was sure howling, tho...

 

Yeah, I'm taking it to the other shop tomorrow. Hoping I won't be out too much more.

 

OK, got the 9-bolt at the new shop. It'll probably be a month or 2 before they get to it, but I saw it as a good sign that the owner immediately knew that there's limited parts available for this diff.