Allison 6sp: Help

[06gmc]

SO last night on my drive home from work I had a hard down shift and it stuck in 4th gear.. I checked the CEL on my edge CTS2 and it was a P0700. Cleared it and truck shifts into 1st the clucks back into 4th gear. Limped home and hooked up the Autocal and it reads P0700 and P0762. Ive done some looking on here and it seems like the problem is a stuck E valve but I wanted to get some more insight.

Truck has 215,xxx. Stock fuel, S&B air intake, deleted and tunes from Rob (90hp economy).

The reason I am asking is cause I haven't seen anyone be able to get it to shift back into first gear and was hoping to be able to get it up and running soon. Thanks guys! :thumb:

 

[Mike L.]

Is the trans stock?

 

[06gmc]

Yes sir, Nothing done to the trans at all

 

[06gmc]

How hard is it to pull the Valve body?

 

[Brandon lynn]

Hello , im having the same issue . P0700 and P0762. Changed the solenoids. Changed the TCM . Heres the weird part. I changed the transmission out . To a used transmission, it fixed the problem i drove 56miles . No issue. Shifted fine. Now i noticed a crack on bellhousing , i pulled it out had the bell housing swapped from my old transmission. Now back to same issue . Stuck in limp mode. Please help

 

[scramHD]

How hard is it to pull the Valve body?

Its not difficult to pull the valve body although you'll have difficulty if you don't have certain things....but...

Appears its time for a new trans build considering the 90hp tuning and high mileage IMO.

 

[Mike L.]

Valve body won't fix the problem.

 

[06gmc]

This problem was resolved awhile ago. It ended up being the internal wiring harness needed replaced along with a new TCM. When we dropped the pan the ATF looked clean with no debris. so we decided it wasn't time for a rebuild just yet. truck ran good and shifted great after it was done