well my rear is now making all kinds of noises (whines, clunks, etc) and i may need to replace it soon. I have a much lower mileage V8 2.73 rear(ugh) that is in good condition with no major problems. I know i will see a major performance reduction but will the car be able to pull itself like normal? I would replace it as soon as possible but in the meantime would it at least be drivable?

On the subject of replacing it would it be better to just get a reman, or rebuild it myself? also would a deeper gear help or hurt me. should Help accel but hurt Mileage right? if so how much gain/loss should i expect.

 

The 2.73 rear will help your gas mileage and make acceleration slower. I plan on going to a 3.73 rear eventually.

 

well stop driving on that rear NOW! It is dangerous, you don't know what is going on there.

I would say replace the rear end with the good V8 one and later change the gears. You car will suck at acceleration but the gas mileage will go up. I would suggest a 3.42 for decent gas mileage and off the line power. It really is a balance, some will say 3.73 to get you going and some like me will say 3+ bucks a gallon says i do 3.42 and keep some economy on the highway.

good luck!

 

My first suggestion would be to open the cover end examine what is going on first. The whining could be caused by worn out rear axle bearings, which are not very hard to change. The clunking could be caused by your drive shaft, possibly a need for new u-joints and needle bearings, also not too hard to do. Unless your pinion and ring gear have gone south, I don't see why you need to go through the trouble of replacing the entire rear end, especially if you are talking about a v6. If you have the space and time to do this, it should not take you more than an afternoon to find all of this stuff out.

 

well when i changed the fluid like a year ago the pin that holds the spider gears in place had some play in it. same with the C-clips but i dont know how much of that is normal and how much is actual wear. when i say it clunks it only does it when i am accelerating at 1/2+ throttle and the trans does 1-2 kinda firm, or when i spin with low throttle on something loose and it grabs, spins,grabs so not a constant thing.

the whine is most noticeable under light load when the diff is cold but is still there if i listen for it when i have been driving for a bit and its warm.

I have a squeek that is most often heard when i brake but not under hard braking but is also there when i turn sometimes as well as when i accelerate at times not a loud squeek but enough to be noticed and its kind of a hit or miss as to if it will do it. I have completely replaced the front and rear brakes. have removed and checked for improper install or any signs of rubbing twice but it still does it. so probably the rear?

so can i do a rebuild without having to have the gears reset? and if i have to have that done can i put it all together and then just have a shop adjust it?

 

If you change the front pinion bearing or differential bearings then you have to re-set the gears. It's not that hard, but let me suggest a plan "C," if you will...

1. Pull your rear diff cover and look inside, as suggested above. Look for any obvious damage like broken parts, teeth missing, or metal pieces in the bottom. If after looking around you decide to replace the rear, don't repair yours.

2. Go wrecking yard hunting and find an 89 or newer rear to rebuild and replace yours with a fresh setup. Is the V8 rear that you have 89 or newer? You want the better 28 spline axle shafts, that's why. If disk brakes are a want of yours, now is the time for that as well. A used 89-92 Z28 or Trans Am rear with disks should be attainable at the wrecking yards. I don't care about disks, myself.

3. Don't run 2.73s. They do not give better mileage; that is a myth. They only gave better mileage at a specific speed during a CAFE and EPA mileage test session by GM to get the car certified at a certain mpg. Real world driving will show that most stock and slightly modified cars get the best mileage with 3.42's or 3.55's - somewhere in that range with overdrive. 2.73's and 3.08's give better mileage with a non overdrive transmission.

If your V8 rear is good, then you can put it in while you rebuild your housing. You only need 28 spline axles and a 4th gen zexel torsen posi with a 3.42-ish gear set. Start junkyarding and you can find what you need.

Good luck!

 

Nothing there to suggest the rear end is bad. Possibly trans mount/u-joints and maybe brake pads.

 

thx for the help, and sorry for posting a drivetrain question in the V6 area at first i only intended to ask about the 2.73s with the V6.

 

I think it's a bad idea...

 

When you have new gears installed, you have to have the pinion depth and backlash set. For pinion depth most manufacturers recommend 0.005" +/- 0.003" tolerance on the depth, then you have to have the backlash and preload set in order to have the correct contact pattern.

You also have to have the pre-load on the pinion bearings set using the crush sleeve. New bearings are typically at 24 in/lb of rotational torque.

It's a very presicion job that really does require special tools in order to do it right. If you want to do it once and have a gearset that's going to last another 20 years, I highly recommend that you take it to a professional and have it done. Most shops will charge right around $750 to do it and as long as they can get the gears and know that you are coming, they should be able to knock it out in less than a day.