Allison 6sp: Think i broke it..

[CarolinaHD]

After making a 100 mile trip, i arrived at the ski slope and put my truck into 4wd to go up a steep, slippery hill. After it went into 4wd i put it in drive and nothing happened. "Shift range inhibited" popped up and after a loud clunk it went into gear. After that it would sporadically clunk in and out of gear while driving and also flashing the message. It got to the point where it stopped moving and only works in reverse. In drive it revs up and slooowly moves forward. Right now its at a dealership near my house but it can't be looked at till monday. It threw a multitude of codes which were:

p0877 x2
p0843 x2
p0848
p0762
p0757
p0751


Also, i had a large puddle of transmission fluid under the truck that appeared to be coming out of the tail shaft of the transfer case. No blown cooling lines or anything like that.

Any help would be appreciated! Just trying to have a little understanding of whats goin on before i hear what the stealership has to say..

 

[tbrowne]

Get it on a level surface and check transmission fluid level - it might be too low.

 

[CarolinaHD]

Dealer called today said fluid was low, put in 8 quarts and got it to move but the fluid is puking out the tail shaft of the transfer case They said they have to remove the transfer case and would call me back. If anyone has any insight it would greatly be appreciated!

 

[IOWA LLY]

Sounds like maybe the input seal of the transfer case is out and fluid from the transmission is getting pumped into the transfer case. I've never seen one do that but its the only explanation I can think of if the transmission is low and not leaking, but the transfer case is.

Sent from my SCH-I535 using Tapatalk 2

 

[CarolinaHD]

Sounds like maybe the input seal of the transfer case is out and fluid from the transmission is getting pumped into the transfer case. I've never seen one do that but its the only explanation I can think of if the transmission is low and not leaking, but the transfer case is.

Sent from my SCH-I535 using Tapatalk 2

I've been looking at diagrams and i believe you are right. However if that was it and its fixed, what caused it to begin with and will it happen again?...

anyone else ever dealt with this?

 

[dmax711]

Man I hope they don't nail you to hard at the dealership..hopefully being that low on fluid didn't damage trans.

 

[CarolinaHD]

Man I hope they don't nail you to hard at the dealership..hopefully being that low on fluid didn't damage trans.

That's the main thing im worried about is getting bent over a rail. He said its up to $300 now to get the t-case off and a couple hours of diagnostic. I hope it turns out to be an easy fix and not get a 2-3 day run around and $1000+ bill....

 

[dmax711]

Well if you need anything I'm in the area. I'd hate to see them nail ya with a large bill for something simple

 

[IOWA LLY]

If its the transfer case seal they will most likely replace it with a re-man transfer case. Which is going to be $1500 plus, and labor.

 

[CarolinaHD]

Well if you need anything I'm in the area. I'd hate to see them nail ya with a large bill for something simple

Thanks glad to see someone close by on the site :thumb:

If its the transfer case seal they will most likely replace it with a re-man transfer case. Which is going to be $1500 plus, and labor.

Well thats not what i wanted to hear... So the whole case has to be replaced not just the seal?

 

[IOWA LLY]

Thanks glad to see someone close by on the site :thumb:



Well thats not what i wanted to hear... So the whole case has to be replaced not just the seal?

No, it can be repaired. It may require more then just a seal. Maybe the input bearing is loose and that's what caused the seal to fail etc. But 9 times out of 10 dealerships wont rebuild things like that. Just install complete re-man components.

 

[dmax711]

No, it can be repaired. It may require more then just a seal. Maybe the input bearing is loose and that's what caused the seal to fail etc. But 9 times out of 10 dealerships wont rebuild things like that. Just install complete re-man components.

Yeah I don't see them repairing it. They do the easiest most expensive thing they can.

 

[CarolinaHD]

well my tailshaft does move 1/8-1/4" all around when you wiggle and i've replaced the rear seal twice. That may be the cause of the failure... either way looks like it needs a new transfer case.

 

[Mike L.]

well my tailshaft does move 1/8-1/4" all around when you wiggle and i've replaced the rear seal twice. That may be the cause of the failure... either way looks like it needs a new transfer case.

Does it move that much with the drive shaft yoke installed?

 

[CarolinaHD]

Yes it does.

 

[Mike L.]

Your rear bushing is worn out and maybe your yoke as well. This would cause havoc with the output speed sensor and cause the trans to malfunction.

 

[CarolinaHD]

Thank you for your input! Would this also cause the front seal to leak and explain why fluid was puking out the tail shaft?

 

[Mike L.]

Thank you for your input! Would this also cause the front seal to leak and explain why fluid was puking out the tail shaft?

First of all; are you sure your front seal on the TC is leaking? Best way to tell is by pulling fill plug and see if fluid is over full. Fluid level should be right at the fill plug opening. Yes the worn bushing and yoke will cause leaks at the output seal. The rear seal is only designed to stop fluid that gets past the bushing which is not very much.

 

[CarolinaHD]

First of all; are you sure your front seal on the TC is leaking? Best way to tell is by pulling fill plug and see if fluid is over full. Fluid level should be right at the fill plug opening. Yes the worn bushing and yoke will cause leaks at the output seal. The rear seal is only designed to stop fluid that gets past the bushing which is not very much.

The transmission was 8 quarts low and the only fluid leak I could find was coming out of the tail shaft of the transfer case. This makes me believe that fluid was forced through the transfer case from the transmission.

 

[Mike L.]

The transmission was 8 quarts low and the only fluid leak I could find was coming out of the tail shaft of the transfer case. This makes me believe that fluid was forced through the transfer case from the transmission.

Very possible but you still have a problem in the TC. It will have to come apart for inspection.