Allison 1000

[MattHugh]

I am wondering about a  Allison 1000 Out of a 2001  Duramax. I was pulling my camper and it went into limp mode. Made it home and hooked computer to the truck and got two codes off of it, the first was P1720 -- Trim Solenoid "A" Controlled Clutch Not Engaged &
P1721 -- Trim Solenoid "B" Controlled Clutch Not Engaged.So we hooked up a Pressure gage to it and no Pressure  at all at the Pressure Tap Plug, so we then dropped the pan and checked the Solenoid A & B Ohms  and they looked to be good. So any advice would be appreciated.