GM transfer Case Pump Rub

lmh64 · December 12, 2017

I am the new owner of a 2001 2500HD 4WD. It has one of the transfer cases subject to the potential GM pump rub trouble. I had never heard of it until I bought the truck and started to learn about it. I don't have access to any of the previous owner's information so I don't know if he had taken the steps to correct the defect which leads to the leakage and potential failure.

My truck has 88K miles and spent it's life pretty much on road in Arizona from what I have determined.

The dilemma is do I pay a shop to take off the case and install the cure, which is available for under $100, at which time I'm sure the shop will want to do all kinds of additional work which only makes sense while they are "in there". Then I have a semi rebuilt case. And the cost will likely be over $1000.

Or should I roll the dice and just wait until the leak appears and go ahead at that time and get a rebuilt for around $1450 plus another $500 to install?

I know there are thousands of these affected trucks out there. I wonder how many actually suffered the leak and transfer case fail? I know those who have gone through it claim it will happen to everyone but then I hear about some who've never had an issue.

I think the years affected are 1998 through 2007. Both 1500s and 2500s.

So: Did you get your truck repaired before the leak occurred? Did you have the leak and then dealt with it? Or are you just driving along waiting? If you reply, please let me know your mileage.

Any feedback would be appreciated.

TIA, Mike

No feedback? No surprise, I guess.. pretty old truck.

So here's the rest of the story. Years back a friend from work told me about a good transmission shop in a neighboring town. While my kids were still driving our cars we had them do three transmissions. I remembered the price was good and the work was great. So this morning I drove over by and had a visit with the owner. He was very familiar with the problem and has done the fix both before and after the pinhole, many times. In fact he said he has two in right now. On Monday I will drop mine off and he's going to install the preventive cure into mine for $325 and he furnishes the part. I bet the Chevy garage would be triple that.

Edited December 14, 2017 by lmh64

dna9656 · December 17, 2017

I used the fix provided by www.merchantauto.com. They have a new oil pump half you can install yourself provided you can get the transfer case back up in its place on the tranny. It's pretty scary opening a transfer case till you do it, it's easy as fishin'! Drain the case, remove the case, get a jack to let it down, its really heavy and the weight is all on one side. Get the case to a clean location, take pictures of it showing the location of brackets etc. so you'll know where everything goes when you put it back together again. Remove the 17 or so bolts, watch for residual fluid. Follow the instructions at merchant auto, take note of the large gear that comes off right after the snap ring it goes back on just like it came off. Install the new part, after you clean the case edges reassemble the case. I let mine sit overnight so the (provided in the kit) sealant would cure without any fluid around (just a personal thing I have) and reinstall the case in the truck, fill it with the GM/AC Delco BLUE fluid you get at the dealer. DO NOT use anything else, I don't care what the label says. Background on this: When I first got the truck (I am the 2nd owner) I got messages on the dash about the 4 X 4, I replaced the red fluid that was in the case from the auto parts store and continued to get messages on the dash about the 4 X 4 needing service. Since I have been using the AC Delco case fluid I have had NO Transfer case messages. Everyone said I had a bad servo on the transfer case/transmission union, or the controller (located on the passenger side behind the kick panel forward of the passenger door. No 4 x 4 issues since.

davester · December 18, 2017

I effectively rebuilt my NP261HD when I upgraded my truck to 4wd (transplanted 4wd from a '06 Sierra 2500 to my '04 Sierra 3500). New bearings, seals, output shaft bushing, friction disc, shift fork was worn, along with a pressed-metal plate that slides over the existing oil pump (vs the more expensive billet replacement pump housing or half-case made of something other than magnesium). The donor truck had about 280k km on it, and the original little clip was still in place, so the case wasn't worn...

GMC-AT · January 8, 2018

I would leave it alone until it leaks..which may be never. My 2000 silverado has 250K and just formed a pin hole leak. I just got the entire back case half replaced. I'm sure some make it 300K + without issues...

gmtech4 · July 8, 2018

Not triple if ya had it done at a dealer , don’t be ridiculous, I can explain flat rate and labour rates if ya like

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Supreme Pizza · July 8, 2018

My thoughts:

Rule number 1: Don't fix it if it ain't broke.

Rule number 2: If it is broken, fix it as economically as possible by shopping around.

$500 to have it installed?!?! No way man. That's a $100 install job - max.

You can easily get a used transfer case for $125 with a 30 day warranty. That is less than what the dealer will charge just to diagnose the problem.

For around $20 more they will extend the warranty to 13 months.

Here is the link:

http://www.picknpull.com/part_pricing.aspx?LocationID=136&NavItem=12&SearchCriteria=&#partpricing

Edited July 8, 2018 by starman8tdc

davester · July 10, 2018

Good luck with getting a shop to remove the old TC and install the new one for $100. Having done this twice myself, with a well equipped garage other than having a lift, and it's not a 1-man-hour job, even with a lift.