GMC transfer case pump rub fix

Status
Not open for further replies.
Joined
Dec 19, 2014
Messages
7
Location
Alabama
Hopefully this will help someone avoid an expensive repair in the future. This problem affects the 1500, 2500, and 3500 series trucks but I'm not 100% certain which year models.

In November I noticed my truck started to "thump" when I let off the brakes after coming to a stop and sometimes as I came to a complete stop. My brakes are in good shape so I assumed the problem was u-joint related. I had a merchant automotive pump rub kit at home so I had my mechanic install the kit and asked him to look at the u-joints for wear. Due to being pressed for time last week he only got around to installing the kit in the transfer case. After driving the truck for 2 days it has not made the thumping noise (which you could easily hear and feel as well) at all. All of the slack I was feeling seems to have disappeared completely. What I thought was interesting was that he told me we installed the pump rub kit at just the right time because it was just starting to show signs of rubbing the back half of the transfer case housing. He said the spot wasn't close to being wore through and I didn't need to do anything else to it. I admit to not knowing exactly how all of those parts interact with one another but my guess is when I started feeling and hearing the thump was when the retaining clip in the transfer case broke and allowed the pump housing to start wearing into the back half of the case. If that was the case, I don't know if it would've lasted another 500 miles or another 50,000 miles but one thing for sure is that it would have ruined the transfer case eventually and I would have had a very expensive repair on my hands. I'm glad I had that kit installed when I did and for me, $285 for the kit and installation is fairly inexpensive insurance for a $1,500 transfer case.
 
A friend of mine told me he had a transfer case replaced under warranty on a 2003 1500 Sierra so I looked around a little more. I found this application table on the merchant automotive website. It says it affects 1998-2007 model 1500, 2500 and 3500 (HD included) series trucks as well as 2002-2007 Avalanche and 1998-2007 Suburban/Tahoe/Yukon.
http://www.merchant-automotive.com/p-4017-transfer-case-pump-upgrade-kit.aspx

That is the kit I purchased but I added the magnetic drain and check plug because a shop rounded off one of the plugs a while back.
 
Last edited:
I've read about this problem before. I am not enthused about spending money for something that may never be a problem. But I don't mind spending a few minutes when I'm under there changing oil anyway.

I was thinking one could smear a large blob of silicone sealer in the area where the break-thru would occur as insurance. I don't care if I use a whole tube or 2 on the thing they're so cheap.
 
I don't know anything about silicon sealer. If it would hold I dont see why it would be a bad thing. The friend of mine who's case was ruined put jb weld on his for a while but I believe the damage was already done by that point. As I understand it, the housing rubs a hole small enough that it only looses fluid when the vehicle is in motion so there is no detectable drip when it is sitting. Eventually it runs out of fluid and.... we know what happens from there. The problem is I don't think anybody can tell you exactly how long it takes after the hole is made before it is destroyed. It may take 10,000 miles, it may take 100 miles. Regular fluid level checks may detect the problem but it may not. If it does happen, and you catch it before it loses all of its fluid it'll still cost close to $500 just to replace the rear case half. Knowing that is why I went ahead and spent the <$300 to fix it before a problem starts.
 
I will have to have a close look at the transfer case on mine next time I am under it. Where exactly is the spot that it rubs through? I have 272,000kms/(169,000 miles?) on my Silverado.
 
Originally Posted By: xxch4osxx
Where exactly is the spot that it rubs through? I have 272,000kms/(169,000 miles?) on my Silverado.


attachment.jpg
 
Originally Posted By: turtlevette
Originally Posted By: xxch4osxx
Where exactly is the spot that it rubs through? I have 272,000kms/(169,000 miles?) on my Silverado.


attachment.jpg

Ah, I see. Thanks for the pic!
 
Originally Posted By: turtlevette
Being the cheap m0 fo that I am.... A bit of JB weld in that area and then some sealant over that would be a poor man's preventative.


My buddy used jb weld and he eventually had the case replaced. I don't know if the problem was already too far along or if the jb weld failed. I talked to him the other day and he said they didn't replace it under warranty like I thought, he had to pay for it himself. He talked like there was a recall later but they wouldn't reimburse him since the work had already been done by a mechanic not associated with GM.
 
I don't mean to be disrespectful but if I owned a vehicle that had this kind of flaw and they had produced it over a period of 7 years, I'd be on the phone with GM and it would probably be my LAST GM ever. There is no excuse for something like this in todays world. GM should be fixing this on their dime, period.
 
Status
Not open for further replies.
Back
Top Bottom