2004 Z71 74,000 miles,,, transfer case starts leaking, seem to be where the case's bolt together, I pull the transfer case and split the two housing, and this is what I found. The tranfer case's GM use have an oil pump that goes over the main shaft, it is free floating and is held in place by the rear case housing to slow the "rocking" of the pump on the shaft there is a small spring tension strip to cushion this,it brokeand let pumprub thecase,everytime you start and stop it would rub, until it rubbed a hole in the case. After doing some research on the web I found this to be very common from 2001-present, some truckwith only 30 to 40,000 mile but most common in the 70,000 and up. GM's fix is JB weld and 12,000 mile warrenty and will not recall or reinberse. I'm telling this because if you own one and notice small oil spot on the ground or oil under the body of your truck check your tranfer case oil asap.

i work at a gm dealership and i see this all of the time. j.b. weld is no fix. there is a small spring steel tab inside the rear half of transfer case that wears out and j.b. weld wont correct this. it is a very poor design, and ther is no improved design to correct this issue. i have one of the transfer cases in my truck that has that transfer case. mine has 150k on it and it is still ok. i dont even know what to do to prevent this problem, but i do fix quite a few at work. not a cheap repair, because you have to replace rear half of transfer case. but most g.m. dealers can correct this under warranty up to 60k miles if they want to without any problems, if you have any kind of history of service or maintanence with em.

bubba they wouldn't even talk about it to me. There is a transmission shop up north that has redesign the pump instead of being about 1/8" thich on the ears or tab he has made it about 1/2 to 3/4" thich which would help on the ware of the houseing I beleive you can do a search for merchant transmission and you'll find it. it cost 250.00, new rear case and seals around 300.00 so it's still ane exspensive repair for something that should have been a recall.

Why I switched away from GM.

I have a 2005 Z71, 27000 miles. Can you do anything ahead of time, before it starts leaking? Is this both on the 3/4 ton and half ton 4X4's ?

it affects 4x4 g.m. trucks that are 1500's, 2500's and 3500's,but i have noticed most of the failures are 1500's you cant do anything to prevent it from happening, but it doesnt happen to all trucks. best thing you can do is keep an eye on it, take a look at it from time to time to detect any seepage, some people dont notice it until it has run dry on fluid and started making noise. if that happens, you can damage some very expensive internal parts, most of the ones i have repaired have been spotted by oil change shops and were repaired before serious damage occured, the only parts needed were the rear half of housing, sealer, fluid, and one seal.

Will you see fluid on the ground ? What side will you see it leaking ? What about these trucks getting stuck in 4 high ?

On mine I noticed some spots on the ground then started noticing drops under the truck on the frame and on the case itself where the two halves bolt together the first hole is about even with the 3rd or 4th bolt to the right of the drain plug.

This isn't a recall ? Will the warranty cover this?

No recall, if your still under warranty they will cover it but, they will replace it with the same type deal and then it can happen again.

This just happened to me on my way home from sandlin on Sunday. My truck and boat were covered with ATF. This is BS. How can so many of these Transfer cases go out and GM does nothing? I was amazed at how many guys spoke up about this on dieselplace.com.

http://dieselplace.com/forum/showthread.php?t=154771

I have 115k miles on my 2500 HD with the Allison.

I found the same fix as you did. $250 for rear housing, $250 for aftermarket pump bracket. I ended up JB welding the case and re-filling it. I'm hoping this lasts a little while until I have the money, time, and desire to fix it right.

Jason

The only thing about the jb weld is with the little spring broke it will let the pump rub against the back housing in several spots, I noticed on mine it had almost rubbed through in three spots and if it does it will drain the fluid very quickly, just keep an eye on it, fix it yourself 500.00 replace it yourself 1200.00. out source it 2500.00.

Just talked to a co-worker who had the same issue. He took it to Marty's Transmissions and had it fixed for $1700. DANG!


I'm going to order the parts this weekend. I'm already getting paranoid that the JB Weld is going to fail.

I've never removed a tansfer case before but I don't wanna pay $1700 to have it fixed. It doesn't look too hard, although I have a torsion bar that may need to be removed before I can get it down. Got any tips?

jta75 sent you a PM

Thanks for the warning. I have a 2001 Z71 w/ 60,000 miles.