GM Transfer Case

I stumbled across this information a while back and thought I should start to look into it. It appears to me that all Chevy/GM four wheel drives from 1998 - 2007 are capable of having this problem. Can anyone shed a light on this.

At what mileage does this issue start?
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Video of Problem
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It used to be that New Process Gear made the transfer cases for GM, Ford, Chrysler. Is this not the case anymore or is this a potential issue on all of them with that style of transfer case I wonder? It looked like an easy fix to me.

I had to put a new transfer case in my 03 gmc before it hit 100,000 miles, developed a vibration at 55 and smoothed out at 65, the vibration came through the floor shifter. It finally wouldn't move on it's own in 2wd. A bearing went out, was replaced and then happened again. Tranny shop fixed it for parts only, then found out the driveshaft was bent, dunno when the heck that happened as it's lived an easy life.
I was told next time to replace with a Jasper unit, as problems have been addressed by them. It still chatters sometimes at 55 in 2wd, but not as bad. Hadn't been in 4wd more than 4 times since new, never on the road.

(quoted from post at 05:57:48 02/18/13) I had to put a new transfer case in my 03 gmc before it hit 100,000 miles, developed a vibration at 55 and smoothed out at 65, the vibration came through the floor shifter. It finally wouldn't move on it's own in 2wd. A bearing went out, was replaced and then happened again. Tranny shop fixed it for parts only, then found out the driveshaft was bent, dunno when the heck that happened as it's lived an easy life.
I was told next time to replace with a Jasper unit, as problems have been addressed by them. It still chatters sometimes at 55 in 2wd, but not as bad. Hadn't been in 4wd more than 4 times since new, never on the road.

Click to expand...

Those old style single post service stations lifts have been know to bend a driveshaft. Has your truck ben lifted on one of'em...

I work in a transmission parts warehouse, and I know all about what you have pictured there. The oil pump in the back of the case rocks back and forth in the lugs they sit in. After some time, they wear a small hole through the rear case half and start to leak oil. The case half is made of magnesium, therefore it can't be welded.
There are several fixes for them. There is an aftermarket rear case half that is made of aluminum, and is much thicker in the area of the pump lugs. In the last year we've sold more than 200 of them. The case you have pictured there appears to have had a small steel plate installed that is one of the fixes. A better one is an item known as a BRNY, or barney as we call them, made by Adapt-A-Case out of Michigan, I believe. They have a website if you want to look at one. A company in Vermont, Sonnax, has another type of repair that is more expensive, but probably isn't any better than the barney.
If the transfer case leaks for too long, it usually burns up all the parts inside from lack of oil, so anybody out there that has a GM product, keep an eye out for small leaks under your truck. If you need more info, e-mail me and I will give you our 800 number and you can call to learn more.
Good luck,
Jeff

Christopher S,
We have a 99 Yukon that has that type of transfer case. We bought it used and low and behold had the transfer case rub that wore thru the case. We replaced it with a rebuilt on at factory cost plus 10%.

We found out it is a very usual problem that can happen as little as 10k or as much as 75k. It mostly is caused by the auto feature in most of the transfer case selection,and can even be in 2 wd selection. As it was stated to me the ring is steel and the case is magnesium type metal (softer) so each time the steel ring is moved,by selecting auto or from 2 to 4wd the ring will spin a little. It doesn't take long to wear thru the softer outer case and causes a leak that will only show up when the vehicle is in motion. After the transfer case has run out of fluid it starves the bearings for lube and seizes the entire unit. A Couple of company's have made some type of aftermarket fix that is supposed to last a long while,but off the top of my head I can't remember their name.

If you have one that leakes, we cleaned the case with denatured alchohol,super glued a patch on went over that with JB weld, It was still holding when we got the new case and installed it.
Hope this helps,
LOU

"It mostly is caused by the auto feature in most of the transfer case selection,and can even be in 2 wd selection."

HORSEPUCKEY! The component that wears against the case is the stationary housing of the gerotor type oil pump. Anytime you are moving FORWARD the rear output shaft is turning, operating the oil pump, forcing the oil pump housing against the inadequate little strip of steel that is supposed to protect the soft aluminum or magnesium transfer case housing from the scuffing wear of the pump wiggling against it.

It has NOTHING to do with whether the unit is in auto 4WD or not.