ack in January, I was going to visit my brother in Texas. 500-miles, one way. I took my '82 RX7, as I'd just had the U-joint replaced on it and the awful horrible shaking had stopped, the dead alternator was replaced, and it was once again a fun car to drive.

The day before I drove it back, there was this exchange:
Me: Hey, what's that grinding noise back there?
Brother: Oh, you need new brake pads on the rear. No biggie. Switch it out when you get home.

In Tulsa, I discovered how horribly wrong he was. Riding up 75 Highway, jamming out to my music, not a care in the world, suddenly my speedometer and my tach both went all the way up, while my car decided to slow down. And stop. And it would not move again. And hey, why is there oil leaking down by the rear wheel? And why, when the car's in neutral with the parking brake off, can I not even push it down this hill?

So I had it towed to a local mechanic. And then an ice storm hit. So after five days of paying for a hotel while these jerkoffs didn't look at my car, but assumed it would cost $1500 to fix, I got a ride back home to Kansas. And then got my dad to tow the car back.

What we've worked out had happened was that the oil leaked out of the transfer case, which caused everything in the rear end to fuse together, which is why the wheels don't turn. The driveshaft, however, turns admirably, so I'm assuming it's okay.

A new rear end is gonna cost me $150. How much expertise do I need to be able to do it without paying a real mechanic, or, alternatively, if I provide the car and the part to a mechanic, what are they likely to charge me?

 

The easiest way to go about this is to get an entire 3rd member replacement. That way you don't have to mess with backlash or gear adjustments. All you do is pull the axles, bolt in the new 3rd member and reinstall the axles, brakes, etc.

While you've got the axles out, it'd be a good idea to change the axle bearings, particuarly since you lost all your rear end oil in the accident.

 

probably a couple hours labor with no warranty since the part is yours.
If its new and doesn't need to be measured or adjusted...I dont think its a big deal. You could definitly do it yourself though..

 

Well i'm confused. First of all your car does not have a transfer case.

It has a transmission and a rear differential. So I assume you are saying all the fluid leaked out of your diff? Your best bet would be to upgrade to a GSL-SE rear end, although it changes your wheel bolt pattern to 114.3x4, it is a LSD rear, with disc brakes.

If everything is fused together inside the diff I wouldn't recommend rebuilding it unless you are really knowledgable and have all the tools at home to do it. But since you are asking if you could do it yourself I would recommend just replacing the whole rear end.

 

Hell, I'm just going by what people told me. The car froze up on the highway, and I noticed a steady drip of oil down in the back. The rear wheels don't turn at all.

 

If the drive shaft turns but the wheels won't, sounds like you may have snapped the pinion shaft. Not an easy or common thing to do. If you have a replacement 3rd member, jack the car up and put jack stands under the rear end. Pull the wheels, brakes, axles, then unbolt the drive shaft and remove the diff as a whole.

If the diff flange has been removed from the new diff, it will need to be reset, along with a new crush tube. Make sure you clean the entire axle housing of any debris and replace both axle bearings.

 

Agreed.

Provided the axle shafts werent damaged in the carnage that occured in the rearend,it should be pretty painless to buy and install a used 3rd member(differential).Its a simple job that only requires basic tools.It sounds like the rearend went dry due to a leaking wheel bearing seal or worn wheel bearing.Be sure to replace the wheel seals and inspect the wheel bearings for roughness when you replace the differential.

Rebuilding a hypoid gear diff is not a job for a beginner,its a fairly techincal task that involves several critical adjustments and special tools required to get it right....and there is almost no room for error.Even with all that,there is a certain "learning curve" involved with doing rearends.It takes a few times before you really get smooth and comfortable doing them.

 

Do the entire rear if you can, it is a simple job with about a dozen bolts, you will need a 1/2 drive set.


Shop should charge about 4 hours, 200 - 400