04.5 Allison Problems

[Jake@HTABR]

Hey guys, i'm working a 2004.5 LLY, We've had this truck in the of the shop over the past few months for various different things suspension and interior related.

Long story short, I pulled the truck in (RAN and drove flawlessly)
I pulled the dash bezel to do a Ipad install, buttoned that up, went to move the truck. Range inhibit popped up on the dash. So okay, i had one of our mechanics change the NSBU for shits and giggs and the problem went away. Another problem popped up now.
When you put the truck in drive it will go into gear normally, but upon acceleration it wants to slip.

What i've found was as you drive, it will throw a code for incorrect gear ratio for the gear your in and when it shifts out of that gear that code will disappear and throw a code for your current gear.

Any input?

Thanks
-Jake

 

[Jake@HTABR]

Anyone?

 

[Slowmax]

By chance do you have access to another TCM?

 

[Jake@HTABR]

I can possibly get my hands on one. Will that affect the tune thats currently in the truck? Im not really familiar with these duramax's. Iirc its got danville tunes loaded on it.

 

[onebaddmaxxx]

Its always easier to diagnose things in stock form.

Is the truck 4x4?

 

[Jake@HTABR]

Yessir it is 4wd, i can take the tune out and go from there.

 

[Jake@HTABR]

I also attempted to put it in 4wd, it will not engage 4wd now. It says service 4wd, so i will look into that this morning. Thank you!

 

[slipclutchms]

sounds like it needs a build. Post some pics of the Ipad install though

 

[Jake@HTABR]

You think its internal? That is the only codes its leaving me with. No other codes, no limp just feels like solenoids aren't holding all the time. Also reverse is all there. One of the guys here just put a steering box in while we were doing the iPad install maybe he knocked a tcm wire or a ground. I guess time to dig into it again!

Oh, and yeah. i will post the iPad install on here as soon as we get the dash painted.

 

[onebaddmaxxx]

i would pull the drain plug in the transfer case and check it to see what it looks like. Im venturing to say the issue might be in the tcase. (A bent fork) It gets pretty common when the pump rubs through. I had the issue in my lb7 and depending on the load of the truck, it would drive for miles ok, and then randomly pop out of gear and hit a neutral like mode and give me incorrect gear ratio codes for whichever gear i was in.

 

[Jake@HTABR]

I drained the transfer case fluid, it sure does look pretty! I also found the output shaft to rear driveline to have a small amount of play and a clunk internally. Hopefully this is the problem. Sad thing is we just had the trans and transfer case out a few months ago for a possible crack in the transmission or transfer case. Ended up being a gasket iirc.

 

[wingnut96]

It worked fine before the iPad install and now it's having problems correct? Think I'd be retracing my step on the install. Connectors, ground etc.

 

[Mike L.]

It worked fine before the iPad install and now it's having problems correct? Think I'd be retracing my step on the install. Connectors, ground etc.

^^^^ This makes sense.

 

[Jake@HTABR]

The only thing that doesn't make sense is all that has been done is a little trimming and fiberglassing on the dash. Didn't mess with anything electrical.

 

[Jake@HTABR]

Well Long story short, brought it to a local transmission shop because we are completely swamped. They are telling us the clutch packs are smoked. Any recommendations for transmission builders?

 

[Mike L.]

Don't believe them.

 

[Jake@HTABR]

What do you mean Mike?

 

[Mike L.]

Have someone qualified diagnose it.

 

[Jake@HTABR]

Okay, i can do that! The transmission has been on the to do list, but if this is the case it just got moved up on the list.