4.88 final drive problems
 

I'll try to be brief, but i need advice!


I had a local shop install the 4.88 gears I got from Weir performance. Right after I dropped it off I had this gut feeling like "something isn't going to go right".

When I picked it up, they mentioned how they had to shim the pinion depth to over 1/4 of an inch, and that something else had to be ground down ever so slightly to fit in the case. (I think it was the ring?) They also said it looked it was made for a full spool.

Long story short, it starting making quite a bit of noise. So i take it back, and they tear it apart and rebuild it. I went and picked it up friday and it's even louder than before! Much Much louder! It sounds terrible.

To be clear, I have no confidence in the this shop's ability, (even though they claim they specialize in rebuilding diffs), but what are the chances I was sent the wrong ring and pinion? Has anyone else had any issues with their install?

The gearing seems about right when I do the gearing/mph calculators, but it definitely doesn't sound good.

Thanks for any help here. I'm a bit frustrated and bummed out. I almost just want to throw my stock 4.10's back in.

The shop fucked up by modifying the parts without your prior consent. Maybe Weir sent you the wrong stuff. You never had a chance to compare them for yourself.

I would take it out and put it back to stock. Then contact Weir Performance and verify you were sent the right parts. If you were sent the right parts, I would not go back to that shop.

if there was doubt the parts were wrong why did they keep going with install? I've bought Weir gears before (4.56) and there was never any mention of grinding

Wow what a shit shop.

Usually shops stop and call the customer when something needs to be modified or can't fit right(the 1/4").
Are they an actual machine shop or drivetrain shop? I've talked to a couple shops for the labor(I provide the parts), and most of them have lied to me about their competence. I wouldn't doubt if it was the same in your area.

Here is a picture of the gears I received from Weir.
http://s12.postimg.org/iy089xg8t/20150814_215909.jpg

The weird thing is this shop did have a lot of good reviews, and has done quite a bit of differential work. I just can't figure out giving a customer back a car knowing it sounds worse than when he dropped it off....that part pisses me off.

I tried calling Weir friday, but never heard back. I'll try again monday. My packing slip from the box it came in says "4.88's for FRS/BRZ".

I just cannot believe a shop would "modify" anything for a car without calling the customer first. That is beyond absurd.

+1 i've had no problem with my 4.56 from weir
I have a really good shop that did my work though, got everything done and installed for $370
It helps that my shop has already had experience with gt86 FD swaps tho

Whats the tooth count on both the ring and pinion?

Not sure. It's currently installed on my car. The car will move and the new gearing matches up with my calculations as far as how far each gear should go. It just sounds terrible, noisy, clunky, etc. under light loads. Under full throttle it's actually quiet.

I've only had bad vibes from this shop. I'm working on getting a refund on a portion of the labor at least to take it somewhere else.

I'll try calling spencer @ weir tomorrow.

Not only has this shop failed miserably at the job, but it's taken them TEN FREAKING days each time they've had my car to get it done. They always had some sort of excuse. So I've literally been out my car for 20 of the last ~40 days.....

Fuck that dude. My car is my DD, the shop I took it to, got everything done in 1 day lol

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