GM 6.0 pump rub?

BigClay

BigClay

Knower of useless ZJ things
Joined
Sep 24, 2008
Location
Winston-Salem
I have heard some talk about a pump rub in a GM 6.0? Can someone give me some more details? I have a 2004 Yukon XL Denali with the 6.0 (this is the all wheel drive 1/2 ton, not a 3/4 ton if that matters), which has ~135k miles on it and I am wondering what this problem is, does it affect my 6.0, and if so what needs to be done to fix it. Thanks!
 
I don't think the 1/2 ton trucks had this issue. I thinkn its only the transfercase behind the 3/4 and 1 ton trucks. But, I could be wrong. It is on a specific transfercase. I know its on the transfercase on a 1999 2500 Suburban with 454 and 4l80 trans. Maybe find out what transfercase that is and see if its the same one you have.

The only way to fix it is to take the TC apart and put a $16 fixed retainer in there to secure the pump instead of the stupid $.06 retainer clip they have from the factory.
 
I have only heard of this happenin on the Duramaxes.The AWD case will be a different animal but might share the same pump set up.
 
rockcity said:
I don't think the 1/2 ton trucks had this issue. I thinkn its only the transfercase behind the 3/4 and 1 ton trucks. But, I could be wrong. It is on a specific transfercase. I know its on the transfercase on a 1999 2500 Suburban with 454 and 4l80 trans. Maybe find out what transfercase that is and see if its the same one you have.

The only way to fix it is to take the TC apart and put a $16 fixed retainer in there to secure the pump instead of the stupid $.06 retainer clip they have from the factory.
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1-tonmudder said:
I have only heard of this happenin on the Duramaxes.The AWD case will be a different animal but might share the same pump set up.
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The 261, and 263 in the 2500HDs and 3500s (regardless of 6.0, 8.1, or Duramax) were subject to this issue. They are the most common to see it, I guess because they put more stress on the driveline as well as the magnesium case material, but the 241/243/246 in the half tons and the AWD NVG149 in the Denali all share the same back half design to the transfer case where the pump rub is an issue. It can happen to any of those, it is just less common in those applications. Your 2004 Denali actually uses a Borg Warner transfer case, you are not subject to any of these issues at all. IIRC 01-02 had the NVG149, 03+ had the BW.

Clay, as mentioned, it has nothing to do with the 6.0, but the transfer case itself. Just check the fluid level at your next oil change, and examine the case, if there is no leak, you are good. What happens is the pump rubs a tiny pinhole (sometimes a larger crack) in the case and lets all the fluid out. The preventative maintenance is to put a steel ring (pump rub fix) in place behind the pump inside the case, if you do that you will never have to worry. If it has already gotten a hole in the case, you have to replace the back half of the case (although I have seen some guys get by with JB weld to plug the hole), on the 241/3/6 cases that are aluminum instead of magnesium you can weld it, can't remember the material on the NVG149. If it is just a hole, and it hasn't leaked dry that is all you need to do. If it leaked dry, it can burn it up and require a new case, or a full rebuild.
 
yeah, don't let it get dry. around town you may not notice it too much and it will likely last a while without oil. But if you go out of town, the 200 miles on the road with no oil will burn it up quick. It happened to me while I was in Myrtle Beach a few years ago. A significant tow bill and rebilding of the case was not an easy pill to swallow on a high mileage 99 surburban. Instead of putting a new back section on the case, I just used JB Weld or epoxy or something similar. To this day its holding up just fine as I see the new owner periodically around town.

I guess if you were comfortable with it and a decent welder, you could weld the magnesium case up. I didn't because I didn't want to chance destroying the case the first time welding magnesium
 
Thanks for the info guys. Sounds like in my particular application I am OK, but I will certainly keep this in mind if I ever upgrade to a 3/4 or 1 ton GM.
 
BigClay said:
Thanks for the info guys. Sounds like in my particular application I am OK, but I will certainly keep this in mind if I ever upgrade to a 3/4 or 1 ton GM.
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1/2 tons still use the same case that is susceptible to the pump rub, just not your special case Denali with the BW case.
 
That 99 Burb should have used an NP241 case. I'd think that's odd to rub through on those...of course anything is possible if it's run dry.

Anything 99 or newer, NBS, with a manual shift t-case will be an NP261 or NP261 HD in the diesels or 8.1s. I had a 261 in my 99 Silverado 5 speed, luckily, I never had any problems.

I have also seen where Dodge had a big problem with this. I believe theirs were with the NP273s. I saw a dually one time with the chain hanging out of the bottom of the case. It was a real, quality item.
 
I didn't think much on the 99 Burb until it happened. After extensive research, it was a common issue, even on that Burb. I can't remember what case it had. 241 doesn't sound familiar but it was years ago and my memory gets worse and worse every day! :lol:
 
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