1975 4 speed: The u bolt straps are solidly suck in my original side yokes on the diff. I had to cut the straps to get the halfshaft out. I'm going to have to drill them out and retap the holes to get the yoke flanges to accept new straps., Would I be better off to buy new side yokes? I've read on this site that the quality and tolerances on the new reproductions may be questionable.

I have not yet measured the endplay of the original side yokes, but a first guess looking would be in the neighborhood of 1/16" of an inch or so.

Thanks,

 

If you are at 1/16” of side play, you need to address that issue concurrently. Some have repaired the worn tips by machining down the end, drilling a small recess and fabricating a hardened “tip” and pressing into the recess. Certainly doable by a good machinist but I am not aware of anyone who has seized the moment and offered it as a repair.

 

While I have not inspected your diff, based on the condition shown in the photos, I would bet you are going to need more than axles. Axle endplay over 020" isn't good, it's usable but not good. Axle endplay over 040" should be addressed and axles alone won't get you into the 005-007 range.

As for axles today
1- new- Chinese, QC all over the place but they were hardened the last I checked.
2- new- Tom's 30 spline, these require machine work and expertise in both machining and differential assembly
3- rebuilt- hardened tips, QC is all over the place, if you get good ones, they're very good, if not you end shipping them back on your dime. Then you have to see what comes in next, I had better odds at the Indian casino.
4- rebuilt- cored, bad idea. It was a bad idea 25 years ago and it's a bad idea today- unless you don't drive the car

Rebuilding your own, yes if you have access to machinery and know what the spec is for length and hardness. If you have to pay someone to do it it's not feasible. I have about 30 cores I will rebuild when I have time, which hasn't been for years. Maybe if I sell off my shop in 7-10 years they will go with it.

 

What would be the recommendation on how to proceed? This car has the original engine, and is more of a touring car. I don't think it's ever done a single burnout and ever had a fully floored 0-60 run. I guess I could say I'd like to have the ability to floor it if I wanted to, but at 180 or so hp, I don't suppose it would have to be super strong.

None of the options presented sound great, so it's difficult to know which way to go. I saw that zip has these for sale. Any experience with their parts? I suppose it's probably they're sourced from the same manufacturer as all the other providers.

 

I rarely use a vendor and don’t recommend any in particular for various reasons.
Most likely the axles sold are the same from most places.
whether or not if you are going to drive the car hard or not, the diff and other units have to be in good condition or the car won’t drive and handle as it should.
Again not having inspected your diff and without seeing any pictures of the inside I can’t tell you how much new axles will help.

 

Do yourself a favor.
Send the rear differential to Gary and let him inspect it.
If it needs rebuilding, there is nobody better to do it correctly than Gary.
Gary built my rear differential, he built my trailing arms and my steering box.
The cost of shipping it to Gary is worth every penny.
He has built hundreds of forum members components.

 

I Googled the name and found Gary Ramadei, however I don't see that he has a website. Does he have his prices listed anywhere? Did a little more digging... hahaha... I guess Gary is GTR1999.

 

Your best bet here is to PM Gary. Perhaps get his Phone number. And talk to him. He's the best. Not the cheapest.
But also He's a fair, straight up guy. I think you will find he's also not the most expensive.
If he wasn't half way around the world I would be having him looking at my diff. !

 

I just found this in my shop yesterday,,
though I'd share.
I hope this is not against the forum rules,,, I seem to get 'busted' by my thought lately ,,

 

Sorry about that, Gary is, Gary Ramadei, and is GTR1999.
Gary doesn’t have a website, office or staff, he is a one man show and works off his reputation alone.
A couple of things you will get if you have Gary build your differential.
You’ll gain a friend, you’ll get the best quality differential in the world, even better than when it was new, and you’ll get hundreds of pictures and detailed descriptions of every little detail of what Gary does.
Whether you’re running a stock drivetrain or super high performance, Gary builds the best.