Vehicle - 85 S10
Engine/trans - V8, 3500 conv, TH350
Rear - 9" maybe 200 miles on brand new build.
Issue - start truck, truck goes into any and all gears, trans feels perfect forward and reverse. You can drive back and forth 400' long driveway 20 times, going from drive to reverse to N to park, to whatever, and no issues. No slipping. Hard launches feel great.
Pull out onto the road, and truck stops moving. Truck acts like it is in N, little throttle or full throttle, truck won't move. But here is the kicker - the speedo registers 35-50mph while sitting still so the speedo gear is spinning. Put in reverse, and speedo goes counter clockwise back around to about 75mph.
Spent 30 minutes pushing truck back to garage. Fired truck up and all gears feel perfect again.
So, what could be broken / not meshing / not adjusted to cause this? The truck sits so fucking low I could not see if the driveshaft was spinning. No odd rear end noises at all.
This is Kenny's old TH350 I got from Marc, and I do not know the history of it's guts.