Allison Help Please!

[tussell21]

Hi everyone! now to the forum and in desprate need of help. I was out on a fishing trip yesterday and blew a trans cooler line on my 2006 2500 duramax with allison. Drained all my oil out and left me stranded. Get my truck hauled home and started to tear into it. pulled off cooler line and made a jumper hose untill i could get a proper line. Filled my trans up with oil and ran through the gears. Went for a rip around town (10 min) came home put it in park and went to drive it in the garage again and no forward gears!!!! reverse works good and when i put it in gear it says Range Shift Inhibited. put the reader on it and got silinoid A &B performance or stuck off. Is she burnt???? has anyone had this before? anything will be helpfull.


Thanks in advence Russ.

[JohnC]

First thing to check is the fluid level. A stop and restart should clear the code if it is intermittent.

[tussell21]

I have checked the oil level over and over again also removed the battery cables for 2 hrs to try and clear anything that might be there. Wondering if there is a sensor of some sort that is in the rad or something that would require the cooler lines to be hooked up proper? also after the hose blew and i got it home it only took about 8 liters of oil.
Thanks again

[DmaxMaverick]

8 liters is about 50% of the total fill.

There are no sensors that monitor the cooler circuit. If the fluid loops from the cooler line outlet to the inlet, the tranny would be oblivious to anything else in that regard. It sounds like you have air in the system, and it can take some time to purge it.

Clearing the PCM will not clear TCM codes. The PCM will only store a "P0700" code, indicating the TCM has stored codes. In any case, every time you turn off then on, it resets the TCM diagnostic cycle. The codes remain, but any condition that isn't repeated will allow continued normal operation (until another fault is detected). It doesn't sound like you did anything that may have caused physical damage to the tranny. It takes a LOT of slippage to actually "burn" it, and since your fluid loss was quick, it didn't have time to operate at low pressure long enough to cause this. The TCM won't allow it, anyway. Once low pressure is detected, it will limp, and only operate in a range it can safely without a local fault.

I suggest repeated attempts to get it to engage. Start, idle for a couple minutes, shift to drive (remain at idle), leave it there for a minute or so, shift to park, shut down, repeat. The air will eventually purge and things should get back to normal. Recheck fluid level once the tranny is up to operating temp. The TCM codes will reset themselves after several start-up cycles without a fault.