Rear End swap help years compatability

[bonester624]

Hey everybody back again. Been a while since I posted about my trans rebuild. No surprise my diff started to take a shh shortly after the trans rebuild. I need help to figuire out if I can make this diff I picked up work with my 2003. Dude said it was off an 2012. I compared it to my diff and it looked pretty much the same but got it home and upon closer inspection there are some sifferences. Was getting reay to swap it over and removed first the driveshaft. Test fitted it to the new diff and it doesnt fit . The u joint pocket is different . the diff has a number on it 40047269B . besides that everything looks the same . I measure it from the diff cover to the pinion yoke and thwyre both 13 inches. Can I make this thing work leta say by switching to mewer u joints? he said it was off a 2012 suburban.

 

[Tonyrodz]

Hey everybody back again. Been a while since I posted about my trans rebuild. No surprise my diff started to take a shh shortly after the trans rebuild. I need help to figuire out if I can make this diff I picked up work with my 2003. Dude said it was off an 2012. I compared it to my diff and it looked pretty much the same but got it home and upon closer inspection there are some sifferences. Was getting reay to swap it over and removed first the driveshaft. Test fitted it to the new diff and it doesnt fit . The u joint pocket is different . the diff has a number on it 40047269B . besides that everything looks the same . I measure it from the diff cover to the pinion yoke and thwyre both 13 inches. Can I make this thing work leta say by switching to mewer u joints? he said it was off a 2012 suburban.

I don't have an answer for you, but if you're 4wd is the gear ratio the same as your old one?

 

[wjburken]

Hey everybody back again. Been a while since I posted about my trans rebuild. No surprise my diff started to take a shh shortly after the trans rebuild. I need help to figuire out if I can make this diff I picked up work with my 2003. Dude said it was off an 2012. I compared it to my diff and it looked pretty much the same but got it home and upon closer inspection there are some sifferences. Was getting reay to swap it over and removed first the driveshaft. Test fitted it to the new diff and it doesnt fit . The u joint pocket is different . the diff has a number on it 40047269B . besides that everything looks the same . I measure it from the diff cover to the pinion yoke and thwyre both 13 inches. Can I make this thing work leta say by switching to mewer u joints? he said it was off a 2012 suburban.

Besides the gear ratio, you will need to look at overall length, brake mounts, shock mounts, etc. you have already found the u-joints are not a match. I know there are differences between the GMT800 and GMT900 platforms.

Why would you not just rebuild the one you have or find a good used one from a part yard from your same platform years?

 

[bonester624]

Dont have the cash for a rebuild or to hit the junkyard at the moment. Wouldnt have been much more money to get one at the junkyard but hey I took a chance on it. Got it for 100 bucks. Junkyard would have cost me like 250 not much more. I checked it out real good and conpared it to my diff and all the brackets for the shocks, sway bar control arms are the same. Brake brackets holes are the same, e brake poaition is the same. Only difference I see is the yoke and the fill hole is on the cover rather than on the case. they measure the same and everything.

 

[wjburken]

Dont have the cash for a rebuild or to hit the junkyard at the moment. Wouldnt have been much more money to get one at the junkyard but hey I took a chance on it. Got it for 100 bucks. Junkyard would have cost me like 250 not much more. I checked it out real good and conpared it to my diff and all the brackets for the shocks, sway bar control arms are the same. Brake brackets holes are the same, e brake poaition is the same. Only difference I see is the yoke and the fill hole is on the cover rather than on the case. they measure the same and everything.

Gotcha. Wasn’t judging, just trying to understand.

 

[bonester624]

I don't have an answer for you, but if you're 4wd is the gear ratio the same as your old one?

Its a 2wd. Dude said it was a 3.08 rear. Mine is 3.42. Not really worried about ratio . I can adjust it in the tune once i get it in there.

 

[bonester624]

Do I just buy a u joint for a 2012? Or buy a conversion u joint. 1.125 to 1.188?

 

[Marky Dissod]

... Dude said it was a 3.08 rear. Mine is 3.42. Not really worried about ratio.
I can adjust it in the tune once i get it in there.

My Z71 4x4 has 3.73, and I am mildly disappointed EVERY time I floor the throttle.
If I could afford to upgrade both axles to 4.10 I would do so in a heartbeat.
You're a better man than I if you can withstand 3.42 ... but 3.08? I wish your 4L60E good luck ...

 

[rockola1971]

Its a 2wd. Dude said it was a 3.08 rear. Mine is 3.42. Not really worried about ratio . I can adjust it in the tune once i get it in there.

3.08 ? Holy cow dude! You arent gonna like it. Have tried searching for the correct rearend on car-parts.com?

 

[Alex_M]

Too big of a deal is being made about the rear end ratio - they came as a factory option, you'll be fine. Folks gotta do what folks gotta do when cash is tight, and you might save some fuel to boot.

You should be able to swap the yoke over from your old rear end but you'll want to get the preload right on the bearing. There's a crush sleeve that should be replaced. They're cheap, order two of you plan to do this in case you over-crush one. on Rock Auto, look under "Drivetrain > Differential Pinion Bearing Baffle"

You'll want a bar type torque wrench to measure preload. The pinion nut can be tightened by hand - put a large-ish pipe wrench on the yoke to keep it from spinning.

However, you also mentioned a conversion u-joint. Yes, you can use a conversion u-joint. Probably a bit pricy, but no more than you'll have in tools/parts to swap the yoke if you don't already have the tools.