I have a 94 K1500 with a 4L60E automatic transmission with 145k+ miles
on it. Lately, it has been getting into a mode where it will start-out
in 2nd gear, and only upshift to 3rd if I manually shift it, and never
upshifts to 4th/OD. Checking the diagnostic code gives me an 81, which
implies a 2-3 shift solenoid failure, or a wiring failure.
My main question is whether I can replace the 2-3 shift solenoid (and
the 1-2 solenoid while I'm at it) while the tranny is still mounted to
the motor (in the truck), or does the transmission need to be removed.
Is there easy access. I can't tell form my service manual, and
crawling under the truck hasn't enlightened me yet either.