The Stupid Axle Questions Thread

[Schurkey]

No doubt it's more complex than this, especially concerning Chassis-Cab models, and the C3500HD. I've never seen underneath, or laid a wrench on either one.

Otherwise, GMT400-family swaps:

2WD rear axles swap into 2WD chassis.
4WD rear axles swap into 4WD chassis. Match front and rear differential gear ratios.

If you change the number of wheel studs--5-lug to 6- or 8-lug, 6-lug to 8-lug, or whatever, you'll need different wheels or some craptastic "adapter/spacer" which then loads the wheel bearings differently due to the wider track width.

If you change gear ratio, you'll also need to deal with speedometer and potentially other vehicle-speed issues unless the gear ratio change is offset by a tire-circumference change.

Things will get more complex if you change from single rear wheel to dual rear wheel.

There is the potential to screw-up brake balance if the replacement axle has significantly-bigger brakes than the OEM axle. 254mm/10" upgraded to 11.x is a nice improvement. 254mm to 13" may not be.

SUVs may have rear sway bar mounts. A pickup axle can swap into an SUV, but you'd lose the rear sway bar which can upset handling. An SUV axle can swap into a pickup, either don't add the sway bar; or modify the vehicle to accept it.

GM is notoriously stingy with locking or limited-slip differentials. Verify before purchase to assure you're getting what you think you're getting. My '97 K2500 had a snow-plow mounted on the front when I got it; but had an open rear differential until I put a TrueTrac in it.

Anyone: Corrections or additions?

 

[drifterwanb666]

Hey yall, i gotta question about rear diffs i cant seem to find an answer for, my 96 tahoe needs the rear end overhauled. Its an open 3.42, 4wd. The front diff exploded a year back and its now 3.73, havent used 4wd since. My question is, i got a limited slip diff outta 01 c1500, can those be interchanged or are the bearings different? Id like to know before i crack my rear end open and then have to just buy a new diff anyway.

 

[Schurkey]

Hey yall, i gotta question about rear diffs i cant seem to find an answer for, my 96 tahoe needs the rear end overhauled. Its an open 3.42, 4wd. The front diff exploded a year back and its now 3.73, havent used 4wd since. My question is, i got a limited slip diff outta 01 c1500, can those be interchanged or are the bearings different? Id like to know before i crack my rear end open and then have to just buy a new diff anyway.

WHICH AXLES are you talking about???

The piece-of-crap 10-bolt 8.5" ring gear? This axle isn't worth putting money into.
The wonderful 14-bolt cover, 9.5" ring gear?
The fairly rare 14-bolt cover, 10.5" ring gear?
Something else? Is your existing axle, and the donor the same? You're not trying to put a 9.5" diff into an 8.5" axle...right?

I don't know the '01 vehicles very well. Kinda guessing it's a locker not a "limited slip".

 

[drifterwanb666]

WHICH AXLES are you talking about???

The piece-of-crap 10-bolt 8.5" ring gear? This axle isn't worth putting money into.
The wonderful 14-bolt cover, 9.5" ring gear?
The fairly rare 14-bolt cover, 10.5" ring gear?
Something else? Is your existing axle, and the donor the same? You're not trying to put a 9.5" diff into an 8.5" axle...right?

I don't know the '01 vehicles very well. Kinda guessing it's a locker not a "limited slip".

Its GM 10bolt, and yes i know thier weak but a 14 bolts near me are crazy pricey. Doner trucks code said G80, GU6.

 

[Schurkey]

Its GM 10bolt,

"It" the original axle? "It" the replacement differential? Both?

Doner trucks code said G80, GU6.

GMT400 G80 is Gov-Lock. I don't know about GMT800. GU6 is indeed 3.42. But it's best to check the actual gears in case someone has already switched them.

 

[drifterwanb666]

"It" the original axle? "It" the replacement differential? Both?


GMT400 G80 is Gov-Lock. I don't know about GMT800. GU6 is indeed 3.42. But it's best to check the actual gears in case someone has already switched them.

"it" is both of them, gears were smoked on doner diff, into scrap pile. I wouldn't think G80 would change from gov-lock, I've always known it as positrack growing up.

I have the entire GMT800 rear end, minus brake calipers, would it be worth it to just use that? and what does it take to go from drum to disc?

 

[Schurkey]

I have the entire GMT800 rear end, minus brake calipers, would it be worth it to just use that? and what does it take to go from drum to disc?

How are your metal-cutting and welding skills?

How many parts do you intend to replace in the process of converting to rear disc brakes?

 

[drifterwanb666]

How are your metal-cutting and welding skills?

How many parts do you intend to replace in the process of converting to rear disc brakes?

i can cut metal weld a dick onna snowman, those dont bother me.

depends on how much I need to replace to swap it. I just did drums/shoes/hardware not too long ago, but if it isnt alot of parts I don't mind converting.

 

[Schurkey]

If you have low-drag front calipers, you'll be replacing both front calipers, the master cylinder, and removing the combination valve to eliminate the hold-off (metering) valve part.

Then you'll have to add a safety-switch and proportioning valve. Or figure out how to disable the hold-off valve in the existing combination valve, saving the safety switch and proportioning valve.

But typically, preserving the park brake is also a hassle. I don't know how the park brake is set up on the newer axles.




It's a lot of work, and a lot of expense, to retain a craptastic 10-bolt axle assembly.

 

[drifterwanb666]

It's a lot of work, and a lot of expense, to retain a craptastic 10-bolt axle assembly.

im mostly sober and i dont fully understand the process, thus i wont ask questions. Except one, that is. But it seems to me its easier to rebuild what i got, although disc brakes are nice.

arent GM 14 bolts 8lug? I was told not to do that, cause that was my first plan.