This is the TH350 in my '70 El Camino, I just put in the new 355" motor, and tried to take it out for a drive, but my transmission wont shift into 2nd gear, but first and reverse work no problem.
I checked the shift linkage, and everything shifts fine, and the transmission is full of fluid (at the "full" on the dipstick with the motor running).
I thought that maybe during the removal and installation of the engine, I messed with the kickdown cable, so I disconnected it from the carb, with no changes.
The transmission worked totally fine about 6 weeks ago when I first pulled the motor out, so I find it hard to believe anything major went wrong/ broke internally from just sitting for 6 weeks. I left the radiator in the car, and did not remove the hard lines to the transmission cooler at all, and I left the transmission in the car during the motor build/ swap.
Also, when driving the car and rolling at about 2000 rpm, I can roll into the throttle and the car wont accelerate at all, the motor just free revs to about 3000 rpm when all of a sudden it "grabs" and takes off. However if I do the same thing from 1500 it pulls right away as it should, but then hits the "dead spot" between 2000-3000.
I basically have no idea other than what I have already checked and tried, have any of you ever encountered this?
Thanks in advance guys