742 3.23 rearend rebuild

[Voss]

Hi,

I am planning to do something about my rearend (742 case, 3.23 ratio). Ever since I bought the car I have had that growling noise coming from the rearend, but only at very light load. It has not become worse or anything, and there are no other strange noise or vibrations. But it would be good to get that differential nice and quiet.

I have done some research and talked to a couple of guys about rebuilding the rearend. I would like to keep the 3.23 ratio since I use the car for ordinary day driving. I found a ring and pinion 3.23 gear set at Nitro Gear & Axle and was wondering if anyone have used their parts for a rebuild? That growling noise really sounds like a worn ring and pinion (or out of alignment), but are there more things to consider here? I'm not the rearend expert so any advice is appreciated. Nitro also had an installation kit with bearings and shims. All in all, it would be about $250 for the gears and $150 for the installation kit.

My other option is to look for a complete rebuilt differential, but it seems like a very expensive way to go... But of course it depends on the cost.

[randy73]

Contact Dr. Diff, I called him and he talked me through everything I needed to do and he knows more about mopar rearends than anybody else.

Search the threads here, there are lots of people singing his praise.

[64dartgt]

Be careful.  I had my 8.75 with a 742 rebuilt by a reputable local shop that has been around forever.  Been on TV...the whole shooting match.  Had new name brand (can't recall which) 3.55's in it that whined like a bitch.  They said all the new stuff comes from China these days and offered me a good used set of 3.23's.  Those are nice and quiet but I have a bad vibration on the highway at 60+mph nobody has been able to diagnose for me.

I dumped a lot of money into my car at supposively "reputable" shops and it all turned out to be a big toilet flush.

Bob