"Pump rub"?

Qwazert · November 15, 2018

So...this prospective buyer tells me I have signs of TC pump rub...........

Since I was totally clueless as to what he was talking about, I did some research and discover that there IS such a thing and that it is not only common...but to be expected! WTF...?

Today, I crawled underneath and had a look for myself...I see no leaking...no wear-holes...and I'd like to think that when my transmission was serviced (in June...and replenished all the fluids down there) that they would/should have mentioned something if they noticed anything...after all, this would be money in their pockets, right?

So is this "pump rub" a defect in ALL GM/Chev products (with transfer cases) or just among certain years?

Mikey52 · November 15, 2018

Had it in an 03 Yukon xl. Supposed to have been fixed in 08.

davester · November 15, 2018

Just certain years, namely, the GMT800 models, from '99 to '07. Later years ('05 or '06 maybe?), they added a little steel clip the case, to try to remedy the problem cheaply, but the clip also has a tendency to break off, so it basically just takes a little longer for the problem to happen.

And there's no "sign" of having TC pump rub until it's rubbed a hole in the case and you see fluid on the underside of the vehicle. You don't typically see a puddle on the ground under your truck because of this problem, as the hole appears above the fill level, so it only comes out while you are driving. I wouldn't count on it being mentioned to you when the truck is serviced, as the hole can happen at anytime, it generally doesn't leave a lot of fluid on or under the truck, and the TC dies pretty quickly once the fluid is gone.

I would suggest figuring out when your truck can be down for a day or two, and get a pump rub plate installed at that time. It doesn't take a lot of time to do, but (IMHO) it's better to do it when it's convenient for you and cheap, rather than after the hole appears, the fluid comes out, and you have to replace a bunch of other parts in the TC, or just replace the whole TC, right when you need to use the truck.

markwilks · November 15, 2018

I read about this when I purchased a 03 2500. I had it looked at and I didn't have a hole or leak. To be on the safe side I had the plate installed. Cost me about $350 at a transmission shop. I'd rather pay now then have to replace the Transfer Case.

Qwazert · November 15, 2018

What is this "plate" you refer to?
Do you have a link?

Thanks.

carkhz316 · November 16, 2018

Just search for transfer case/ pump rub plate and you'll find the BRNY or similar anti-wear insert for your transfer case. Merchant Automotive also has a billet pump have that is a little more robust but a few more $$$. davester is completely right that there is no real sign of rub until it's already leaking. All of the NP246/243/261/263s from the late 90's through mid 2000s will experience it eventually, not if. So, your prospective buyer is a kind of a moron.

PrairieGM · November 16, 2018

I can attest to the Merchant product. My '99 had that happen after I got the pickup. I actually caught it after it had rubbed a hole but before it cratered the Tcase. I bought a new rear half case off Amazon and the kit for the shop to do, haven't had a problem since. Yeah it's really hard to find, it's just a small pinhole leak that took awhile to track down. For me, my torsion bar was wet which helped me find it. Hope this helps.

Qwazert · November 16, 2018

So is the wear-hole (is that a word?) on top of the TC or on the bottom?

carkhz316 · November 16, 2018

It's usually near the bottom, in about the 4/5 oclock position when viewing from the rear of the case looking towards the front of the truck though it can rub through at any of the pump index spots. I've seen them at the top and other times, the bottom of the TC.

PrairieGM · November 16, 2018

I agree with carkhaz316, though for reference mine was closer to the 2 o'clock position if I remember correctly. Been awhile, but hope that helps

Qwazert · November 16, 2018

So basically...anywhere in the forward-facing part of the TC.

davester · November 16, 2018

No, it's on the rear-facing part of the TC. I would suggest using google images for gm pump rub, to see pics of where the hole happens, if you want to see it.