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Leaking Np246 Transfer Case

drag230

By drag230
in Ask A GM Technician

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drag230 Enthusiast

drag230

Posted
Posted

I have a 2002 Yukon XL 2500 with an 8.1 liter engine. It has 75,000 miles on it. It has a New Process 246 transfer case assembly number 1577 2806. I found a pin hole in the rear of the transfer case on the right side where the rear drive shaft exits. It is Not on the tail shaft of the transfer case. It is about where the tail shafts starts. I repaired it with JB Weld (had to, I was 1,500 miles from home) and thought I should check into it. Keep in mind this suddenly happened and started over night. I have heard this is a common problem with these transfer cases. I have heard that something is failing inside that caused the pin hole. Is this True? This was a GM certified used vehicle. Does GM have any recalls on this? Do I have a case to get the dealer to repair at a reduced cost or even free? LOL!!! I consider myself a better than average shade tree mechanic. I build all my drag motors and restore old Pontiacs. Is this something I should just repair myself? If so, do you know a good source for rebuild kits. Thanks for the help in advance. John

  • 4 weeks later...
5Alive Enthusiast

5Alive

Posted
Posted

To get more information about this problem, I'd recommend visiting thedieselplace.com .

 

There is a spring clip that seats inside of nook on the transfercase that helps retain the pump, which rotates at driveshaft speeds all the time, even in 2WD. When that clip unseats, the "pump rub" issue eventually manifests itself, as the magnesium housing gets rubbed in a concentrated area and thus worn thin/beaten enough until it rubs through.

 

The issue is reported more often with 261 and 263 cases, that are mated with the Duramax/Allison, more so than with the 246 cases. That's why I recommend the the gm diesel truck user website mentioned above.

 

New Process designed a new replacement pump retainer clip that is available through GM parts, or, alternatively, you can contact Dan Merchant at Merchantautomotive.com, who designed a more robust cnc machined pump retainer that has been a popular fix amongst the GM diesel truck owners.

 

I dread this problem surfacing in my similar out of warranty 2500 YXL, so that is why I try to keep up to date on this subject. It is a cost cutting, under engineered design defect, according to an inside source at NP/NV, the supplier of the TC, who reportedly tried to warn GM that problems would surface, but was forced to go with the lower cost option until the problem became widespread. There is no recall because it is not a safety issue. It's just an issue that makes one think twice before buying another GM vehicle.

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