GMC Jimmy

I have a 2000 GMC Jimmy 4WD with 4 spd AT. Mileage is 97,000.
Truck does not downshift to first gear at stops. If I manually downshift, it will start out in 2nd and upshift normally. If I don't downshift, it tries to start in drive.
Error code reads " Stuck transmission solenoid". This problem occured all at once. It didn't happen gradually.
Is this solenoid something that I can replace myself. Or am I stuck with a transmission shop.
Does the valve body have to be removed?

Truck is in beautiful shape otherwise. Runs great and looks great.
Thanks in advance.
May 11, 2007.

I am experiencing the same thing with my 96 GMC Jimmy (4.3L V6, AT). After looking around, I have heard a lot about the 2-3 solenoid, but I haven't been able to nail it down, or get any information on the repair/replacement. Have you had any luck?

Jul 26, 2007.