ATF in hubs, but intercooler not damaged. How?

[PBR Streetgang]

I bought an '86 M998 about a month ago. Being new to MVs, I took it to the former Hummer dealer to look it over. Maybe a mistake, maybe not... I figured they would know best what it needed, and given that I don't have a lift, I wasn't sure that I could lure an E5 from Fort Lewis to come check out the vehicle.

Bottom line: Nearly every seal and gasket was original and needed to be replaced. To their credit, they took me into the service bay and showed me the seals - the seals were bad and were leaking.

When they took off the wheels and hubs, the hubs were filled with fluid. Service bulletin says look for a broker intercooler. Checked the intercooler, but it's fine. So - question for the Reasonably Knowledgeable Individuals: Where's the fluid coming from and how? I've been instructed to drive the truck for 500 miles and come back to check fluids, but since I don't (yet) drive my truck too often, it might be 6 months or more before I can put 500 miles on it.

Ideas?

PBR

 

[Haasino]

ATF Vampire... [LINK]

Stop driving the truck immediately... tow it back to the shop... if they're a Hummer dealer, they should've know about this issue.

 

[PBR Streetgang]

Crap, crap, crap. Thanks Haasino. I was searching the Hummer Knowledge Base about 4L80 trannys and saw that link - just didnt get to there yet.

If it floats, flies, has wheels, or tits...

jas

 

[emmado22]

You got the Vampire......

 

[PBR Streetgang]

Just got off the phone with the dealer. He says they tested the intercooler and put 60psi air pressure through it - it tested fine and wasn't damaged. What's the chance they're wrong? If I have the vampire and the crack is small, could it hold pressure for a few minutes and not leak significantly enough to show up?

Dealer is saying the intercooler isn't damaged and not to worry about it. I'm skeptical.

jas

 

[BLK HMMWV]

Does your truck have a fording valve or the fording set up. It was usually only found on ex Marine HMMWV this could possibly be a reason as well if your sure the loop isn't cracked. Or possibly the guy who owned it before you put the wrong fluids in the hubs

The vampire effects the transfer case , hubs, and air filter what did the air filter look like?
If you put 60 psi through the intercooler loop and it held I doubt you have a crack in your loop. If you have a cracked loop it will fill up your T-case completely full. If you take off the upper inspection plug on your T-case the proper fluid level should be at the bottom of the hole, if a bunch of fluids flow out then it is being syphoned from your trans via a crack in the loop.

You have a TM for your truck yet. That has a bunch of useful info in it.
It tells you how to check the hubs for proper fluid levels and also what kind of fluids to add to them.

 

[battlebuggy]

I agree on the air filter check. Also it is not uncommon for people to put ATF in the hubs to try to improve fuel mileage. Since you are a new owner of this vehicle you may find all kinds of stuff that you will change to the way you want it from the way someone else did it. I would be pleased if the stealership did the cooling loop test and it passed. That is a load off your mind.

 

[PBR Streetgang]

RTFM... got it.

My truck is an Ex-Marine vehicle, and it's set up with a fording kit. The switch 's in the vent position. I'll check that system.

Thank you for all of the responses.

PBR

 

[TedG]

Perhaps they are calling the intercooler (air to air) is the radiator portion of the triple cooler (oil, tranny, ps) which is air to wet. The cooling loop for the tranny also sends aft into the tcase cooling loop (wet to wet). The tcase cooling loop is what can typically leaks. If they pressure tested the tranny cooler of the triple cooler, then they would not find a problem. They need to pressure test the tcase cooler at the tcase. OR bypass the tcase cooler (ie don't use it).

 

[PBR Streetgang]

Update:

The cooling loop in the transfer case was not damaged - since being serviced, there has been no ATF in the hubs or air filter.

There was still an ATF leak, which we tracked down to a loose vent at the top inside of the transfer case. So far, so good...

PBR