[BigBass Hole]

So-

While driving around 45mph and above, I can hear a very faint growling noise coming from what sounds to be the middle of the rear end. I can also, at times, hear a slight "grind" when I drive off at about 5mph. I lifted the '04 Envoy SLT up from the rear and put it on jackstands. I grabbed the drive shaft and turned it and it had about a 1/2" play in it either direction. Next, I grabbed the rear tires and it had about 1" play forward and backward (not in and out). Is this normal? Could the gears be so worn that the differential doesn't "catch" as it should? Also, I removed the diff. plate and inspected the gears. I did not see anything worn or out-of-the ordinary. There was, however, gear oil on the undercarriage and the diff. itself and this positively indicated a bad diff. seal which I was about to replace. BUT, the backplates were completely rusted out. BTW, the vent line was clear and clog free so that eliminated it as a suspect.

A few questions:

1. What are the advantages/benefits of replacing my rear axle assembly with an axle assy. from an EXT that has the 8.6" gear in it (keep in mind that I have the G80, GT4 3:73 locker); are there any advantages?

2. If I did replace the whole rear end, would I need a spring compressing tool to remove or separate the springs from the wheel wells and axle ?

3. On a new rear end, how will I know if the pinion bolt is set to the proper torque or will it most likely be set correctly?

4. Any way to properly identify what type of rear axle assembly I am purchasing especially if I purchase it from a junk yard?

Any thoughts or ideas would be greatly appreciated!

 

[WOOLUF1952]

1. What are the advantages/benefits of replacing my rear axle assembly with an axle assy. from an EXT that has the 8.6" gear in it (keep in mind that I have the G80, GT4 3:73 locker); are there any advantages?

The advantage would be a stronger rear end.
However, since you have 276k miles on your present set-up, it doesn't seem like that would be needed.

2. If I did replace the whole rear end, would I need a spring compressing tool to remove or separate the springs from the wheel wells and axle ?

No. You can remove the springs by disconnecting the shocks and jacking up the truck.

3. On a new rear end, how will I know if the pinion bolt is set to the proper torque or will it most likely be set correctly?

It should already be set.


4. Any way to properly identify what type of rear axle assembly I am purchasing especially if I purchase it from a junk yard?

The easiest way is to check the sticker in the glove box of the donor truck, if it's available.

 

[BigBass Hole]

Hey WOOLUF thanks for the input!

How would I go about compressing the springs to get them back on the new axle then? If I do replace the whole axle assembly, is my best bet to just look around for a 8.6" rear or just stick to the 8" :bonk:

 

[steveO]

When I replaced my rear axle I put my floor jack in the center of the axle and jacked it up slowly and inspected them to be sure they ad seated properly. The axle set right into the cup on the jack.

The springs are going to be relaxed if you have the truck up on jack stands with the wheels suspended in the air. You just need to jack it up enough to get the bolts back in.

I did mine by myself, it was much easier than anticipated.

 

[gmac310]

When I replaced my rear axle I put my floor jack in the center of the axle and jacked it up slowly and inspected them to be sure they ad seated properly. The axle set right into the cup on the jack.

The springs are going to be relaxed if you have the truck up on jack stands with the wheels suspended in the air. You just need to jack it up enough to get the bolts back in.

I did mine by myself, it was much easier than anticipated.

:iagree: There is enough travel in the rear arms/links to allow the springs to slip in their seats and then just jack up the rear diff to compress them. The shock's length will help hold them in place.