Finding my ratio

[Dougnsalem]

I don't think anything cast into the axle is going to give gear information. That same casting will be used for several options. You need to clean (wire wheel, sand, whatever) the build up off the tube, and look for anything actually STAMPED into the tubes. Iirc it would be on one tube or the other, near the diff on the side facing the front of the truck.

This is one that I always thought was BS.... Until I actually saw myself. Have a few times now, in really small numbers. Kinda cool....

 

[78C10BigTen]

Also, FWIW, the build date really doesn't change anything across the board. All you need to do is determine what it is... And that can be done my looking at the rear pumpkin and counting the bolts on the Diff cover (for half ton trucks). If you have 10 its a 10 bolt, 12= 12 bolt. If you have the 10 bolt for sure then all you need to change gearing is the setup kit, the knowledge, and the ring and gear. If you have a 12 bolt then it can be a little more complicated because of the 3.73 cutoff on the carrier (if you don't have a 12 bolt don't ask, lol).

Shes a 12....

 

[rpcraft]

This is one that I always thought was BS.... Until I actually saw myself. Have a few times now, in really small numbers. Kinda cool....

Swing and a miss.... Whatever is stamped on the exterior axle parts is not relevant because it may have been changed at some point.... Open the diff, and read the stamping on the ring gear, or jack it up and rotate the tire and count how many times the driveshaft spins in relation to one rotation of the tire.

 

[78C10BigTen]

Swing and a miss.... Whatever is stamped on the exterior axle parts is not relevant because it may have been changed at some point.... Open the diff, and read the stamping on the ring gear, or jack it up and rotate the tire and count how many times the driveshaft spins in relation to one rotation of the tire.

i may be wrong...... i had originally posted this thread sayin its a 10 but i counted 12 tonite... hmmm. Ill have to recount tomorrow in the sun light.

 

[rpcraft]

Long story short is GM 12 bolts have a different carrier series for above or below 3.73. Anything 3.73 and above is a 4 series carrier and anything lower is a 3 series carrier. but if you want 3.73 gears you can buy a deep cut set to bridge the gap of the carrier series. It's usually not an issue not an issue unless you have a 4 x 4 with bigger tires (like 33 and up). The most common carrier is the three series. Alternatively if you want a 3.73 you might be able to just swap a 10 bolt out of a early 90's Z71 but I am not sure if the shock and spring pads are in the right spot or not (never looked at the ability to do it).

 

[Dougnsalem]

Swing and a miss.... Whatever is stamped on the exterior axle parts is not relevant because it may have been changed at some point.... Open the diff, and read the stamping on the ring gear, or jack it up and rotate the tire and count how many times the driveshaft spins in relation to one rotation of the tire.

Yeah, I realize that. I yank the cover on any I get. There could be a posi in there with burnt up clutches, acting like an open carrier. I'm just saying that I always considered the stamped tubes to be an urban legend. Until I actually saw them.

 

[rpcraft]

i may be wrong...... i had originally posted this thread sayin its a 10 but i counted 12 tonite... hmmm. Ill have to recount tomorrow in the sun light.

The reason I brought it up is because that casting number is the part # for GM 12 bolts, so glad I questioned it. I think you are probably right on your most recent count though so don't fret it too much.

 

[78C10BigTen]

The reason I brought it up is because that casting number is the part # for GM 12 bolts, so glad I questioned it. I think you are probably right on your most recent count though so don't fret it too much.

I do know its a factory limited slip option

 

[78C10BigTen]

The reason I brought it up is because that casting number is the part # for GM 12 bolts, so glad I questioned it. I think you are probably right on your most recent count though so don't fret it too much.

I tagged you in the original post where the picture of it was. Its a 12

 

[rpcraft]

If it was a Gov-Lock then it is probably broken, most likely the first time someone spun the tires, and that is a far more realistic explanation for what may not be working.... I take it the RPO tag is not on the glove box lid as they usually were?

 

[78C10BigTen]

If it was a Gov-Lock then it is probably broken, most likely the first time someone spun the tires, and that is a far more realistic explanation for what may not be working.... I take it the RPO tag is not on the glove box lid as they usually were?

Here it is. And ive spun them many times in the snow and it seems only 1 ever spins...

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[Dougnsalem]

This is your second thread on this, and you haven't taken off the cover yet?

 

[rpcraft]

G80 option is the Gov lock LSD-- It's garbage and about 99.99 % chance it is broken... The reason is because the way it locks is mechanical, and the clutch should actually should be called a governor, and the only way it engages is when it detects a sudden high speed slippage so the wheel is torquing hard when it slips, and it's designed to be a slow speed engagement and disable over about 20 mph (or so), but when the mechanical disengagement kicks out, the results can sometimes be explosive. It's a horrible sound, but if you have broken one you will know it when you hear it. Usually its the result of burnouts and then the tires getting sudden traction, unexpectedly in the middle of a burnout.

You can hear it crunch at 1:32 on this video, lol....

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[rpcraft]

and technically its supposed to be a Posi-traction, not LSD..... and I think that is the nature of why they snap.

 

[78C10BigTen]

If its broke will it still drive