my allison has developed a leak which seems to be coming from where the tranny and transfer case adapter meet. i have fluid all over the crossmember. the truck has 56000 miles on it. is it just a seal that can be replaced or is it something worse. it still is under warranty till 60000, but i would like to get an idea what to expect before i take it to the dealer. any idea's would be appreciated, thanks

The fluid may be coming out of the transmission vent. Fluid will sometimes vent from the case if it's overfilled or gets too hot. The vent is located on the top rear of the transmission. If this is dry then you probably just need a new gasket.

It would be a good idea to have the transmission adapter housing to T-case inspected. There have been reports of the housing cracking due to driveline issues.

my allison it still is under warranty till 60000, but i would like to get an idea what to expect before i take it to the dealer. any idea's would be appreciated, thanks

I thought the Allison was warrantied till 100,000?? My trannie has sprung a leak that looks like it is coming from between the motor and trans:mad: I just noticed it the other day.

Allison warranty is under the standard 3yr 36000 warranty. The Engine has a 5yr 100,000 mile warranty with a $100.00 deductible after the 3yr 36,000 mile warranty is up.

It would be a good idea to have the transmission adapter housing to T-case inspected. There have been reports of the housing cracking due to driveline issues.


Any body know anything else about this? Something blew on mine last nigt after driving a couple hours. It evidently started leaking while driving (never got over 150* though) because there was ATF all along the passenger side under carriage and on the tailgate and bumper. When I stopped to fuel up, I went to back up, it moved normally for 20ft then acted like it popped out of gear. I checked the indicator and switched it but, nothing. So I look up near the pump I puleld away from and there is a puddle of fluid half as big as a couch. I get parked, crawl under the truck and there is a fluid all over the tail of the trans., x-case and everything on the passenger side under carriage.

I finally got it hauled home late last night and am just getting in from church to get back under it to investigate more. I plan to add some fluid get it engaging again and try to see where the fluid is coming from.

If it is this cracked case, how costly is that item to replace?


thanks,

Smoke Show
Mitch

clean it off and see where its leaking... thats step one

How much fluid does it hold?

Smoke Show
Mitch

5 gallons on overhaul

okay....

So I get it wiped down, get it topped off on the "cold" side, chock the tires, sey the parking brake, put it in Drive and crawl under to inspect........

What I find next is ATF pouring onto the ground (this sucks but should make finding a leak relatively easy) so I hurridly scramble to get me big a$$ under teh truck to see just where it is coming from. I got my look, seen how much ATF it had already lost and decided I would continue my investigation with the truck turned off and in Park.

So I crawl back under and look at the problem area.... It appears to be coming from the lower right bolts/seal where the x-case mates the Alli. I don't see any visible cracks BUT there is a vane on the x-case taht I want to look at from the top to see if it is cracked above it, running to the edge and pouring off the bolts.

So I get armed with a flashlight and mirror but still don't see any cracks and there isn't much fresh ATF above the vane.

From what I can tell, it appears that the seal has blown between the x-case and the Alli. I'm trying to find some batteries so I can get a picture of the area so you all more fully understand what I mean about the vane and where I'm talking about.


QUESTION: Anyone think something different? How hard to replace this seal? How should I service the x-case and Alli. once the leak is found?


Thanks,

Smoke Show
Mitch

Unless the bolts came loose between transfer case and Ally I don't think it is the gasket. Possible crack in housing but more likely overfull Ally. The fluid should not be at the cold mark when warm but in the center of the hot grid.

Since all of this happened, I have not checked the ATF level while at proper operating temp. When it all first happened at the fuel station, I did check to verify that it was ATF and seen that the level was well BELOW even the cold mark only a minute or two after shutting the truck down. From that point until I got to investigating it today, I never added a drop.

When I checked the level this evening it was still well below the cold mark. So I added a quart of ATF and performed the aformentioned process of watching ATF POUR from the Alli. adaptor/x-case.

I ran out of daylight to check the tightness of the bolts where most of the flow was, so I'll do that tomorrow. I can't imagine they were tight enough to hold, then all of a sudden they weren't and sprung a BIG leak but I'll check them anyways. It still seems like the flow was coming from between the two members as if a seal had blown. I can't imaging why it woud have blown for no reason and don't hear of this much, at least not on here. Does this happen, the seal blow out there?


I tried to get my camara to work but had no luck so pictures will have to wait.


ANY OTHER IDEAS?????



Smoke Show
Mitch

Hope you get er back together Mitch. I know on my truck there is no seal between tranny/transfer case. If its close to the same as a Dodge, then it shouldnt be a hard job taking the t-case out, but that low lying frame will suck without a lift. Good luck, and let us know what you find.

Eric

Thanks, and yes the low frame may end up being my enemy.

There is something I forgot to mention, it did through an SES code. Not sure what it is and don't know how to check it.


Smoke Show
Mitch

I've got the same problem .04 Duramac . I've heard of lots of transmissions having the front seal problem , but I was reassured that they had changed the design and I would have no problems. So now at 68000 Kms or 42000 miles I have a leaky front seal that is 840.00 worth of labour to fix . Just past warranty . Has chevy stepped up and done anything about this .

I've got the same problem .04 Duramac . I've heard of lots of transmissions having the front seal problem , but I was reassured that they had changed the design and I would have no problems. So now at 68000 Kms or 42000 miles I have a leaky front seal that is 840.00 worth of labour to fix . Just past warranty . Has chevy stepped up and done anything about this .

I don't believe it's a seal. 840.00 is too much money for labor.
mike

Mitch, sounds like a rear housing more then a gasket based on your description.

Thats what I'm thinking too BUT I haven't found the/a crack yet so I'll assume its a seal until then. It is going to a shop Thurs to be looked over and determined what exactly is leaking and why. From that point, I'll make a move.

Would someone PLEASE PM me a quote for a new version adapter case. I'll also want the SC brace. I'm thinking those two parts will be around $500??? Am I on the right path for that assesment.

The MAIN thing is I HAVE to find out what made the seal blow OR the case to crack in the first place. As some know from my other posts, I'm dealing with a vibration/shutter that seems to be coming from the front driver's side tire area BUT I think I have heard of driveline issues (out of balance or bad joints, etc.) causing the case to crack. All said, the cause MUST be determined at the time this repair is made so I don't find myself making it again in the future.


Thanks all for replying, I really appreciate it. I'll keep everyone posted on what the shop determines is actually leaking and their assesment on how to fix it.


Smoke Show
Mitch