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T-Case slow leak

LagunaH1

Well-Known Member
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3,697
Location
Lake Forest, CA
The t-case on my '97 seem to have a slow leak, about 1 - 2 drops a week. To me, being the layman I am, that doesn't seem like very much.

Does this fall in the "normal for an H1" category?
 

Bigunit

Hammer Down!
Staff member
Messages
6,558
Location
Arizona
Mikkel, I'll call my HUMMER service rep buddy here in Tucson & see what he says but, me personally, I don't like to se any leaks coming from under the truck but maybe it's "normal for an H!".
 

3Hummers

Super Moderator
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10,391
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Central Texas
H1s leak but I try to correct every one. Where is the leak coming from? Have you tightened the case bolts and hose clamps? Had it serviced recently?
 
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Kurt

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Messages
955
Location
Orange County, CA
Try to figure out where it's leaking.

I had a similar leak and it was the rear output seal, I checked the levels every few months and it was fine for a while. I left it like that for 2 years and when I had major drive line work [differential installation and lockers] thats when I had the seal replaced.
 

LagunaH1

Well-Known Member
Messages
3,697
Location
Lake Forest, CA
Yesterday I wiped the T case clean and will be keeping a close eye on the leak for the next few days. I'll also want to see if I can determine the fluid level in the T case, very much along the lines of what Kurt is saying. I am thinking that if it's a "stable" slow leak at about one drop every few days and there's plenty of fluid in the t case it may not be something that needs attention right away. If, on the other hand, the fluid level is low then it needs to be looked at.

I had the transmission serviced recently, but I don't think they touched the t case.

Edit: Went out and looked at the T case in daylight. It's obviously quite a bit dirtier than I thought last night but that's not the problem. I took a few photos and I *think* this might be where the leak is coming from:

IMG_0773.jpg


-Simply because it's the highest point on the T case that is wet, and since fluid will run down, and not up, I would suspect this to be the point that leaks.
 
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Bigunit

Hammer Down!
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Arizona
My HUMMER service rep friend just said the same thing as Dave & Kurt. If it's 1 drop or 2/week, not a big worry for now, but you should try to figure out where it's coming from. He said the most common TC leaks are 1) the TC gasket seal, 2) output shaft seal, or 3) input shaft seal. You have about 2 quarts of TC fluid in there but since you don't know how much is still left, you may want to take it in & have them check it out and fix the leak. If the leak just started, you should still have enoough fluid for a while.
 

3Hummers

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The top bolt in the case is the fill opening. Should be filled up to that hole. You can remove the bolt and stick your your finger in. If the fluid is right there you have plenty of fluid. If you need to add some the easiest way is with a hand pump.
 

3Hummers

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Mikkel, seems like it is an odd size nut. Can't remember but I think it requires a 35mm socket. If you don't have one I do. Let me know.
 

Kurt

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Messages
955
Location
Orange County, CA
Btw if a bit of ATF spills out, it's acceptible if it's just a few oz. Basically as long as you can feel ATF with your finger, you should be good.
 

MaxPF

AGNTSA
Messages
1,394
Location
The dark side of the globe
Looks like the shifter seal is leaking. As a rule, it doesn't make sense to fix one leaky part of the t-case. Since you have to pull it and disassemble it anyway, it is best to throw a complete seal kit at it.
 

LagunaH1

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Messages
3,697
Location
Lake Forest, CA
As it turns out, the fill plug is not a 35 mm nut. I'm guessing more like a 25 mm. Either way, I'll be picking up a crescent wrench today. I thought I had one but I guess it got lost in the most recent move.
 

LagunaH1

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Messages
3,697
Location
Lake Forest, CA
Having done a bit of research, I think I'm down to 2 possibilities:

1: T-case was overfilled during last service
2: The T-Case cooling loop has cracked or failed, resulting in transmission fluid being pumped in to the T-case

Over the next number of days I'll be watching the fluid levels real close. If the transmission fluid level goes down while the T-case fluid level goes up, then it is most likely the cooling loop.
 

3Hummers

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92 is in the shop also. Hope Mike can get to the trucks. I was there yesterday and the poor guy is still buried. Trucks come on faster than he can get them out.
 

LagunaH1

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Messages
3,697
Location
Lake Forest, CA
Word from Mike @ Tustin is that it indeed is a matter with the cooling loop. Hopefully the truck should be done in a weeks time from today.
 
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