chengny
Full Access Member
- Joined
- Feb 22, 2012
- Posts
- 4,084
- Reaction score
- 1,024
- Location
- NH
- First Name
- Jerry
- Truck Year
- 1986
- Truck Model
- K3500
- Engine Size
- 350/5.7
Two easy things to check:
1. That the detent switch on the gas pedal/carb is open. I am no transmission expert but I am fairly certain that, while a TH400 will do a forced 1-2-3 upshift even with the kickdown (detent) valve hung open, it requires the RPM to be really high - something like 5K.
2. The condition of the vacuum tube (that runs from the intake manifold down to the modulator) - especially the rubber sections at the ends.
1. That the detent switch on the gas pedal/carb is open. I am no transmission expert but I am fairly certain that, while a TH400 will do a forced 1-2-3 upshift even with the kickdown (detent) valve hung open, it requires the RPM to be really high - something like 5K.
2. The condition of the vacuum tube (that runs from the intake manifold down to the modulator) - especially the rubber sections at the ends.
