Had S10 trans checked before build, the shop said it was great.....but it jumps out of first gear as soon as the clutch is released, can't even hold it in place...but it works fine in all the other gears, very drivable. I put the shifter mechanism back on myself, did I do something wrong maybe? It all LOOKS fine, but jumps out. ideas? It is not hitting the floor or anything that simple.
Are you using an aftermarket shifter with adjustable stops? If so you may need to adjust the stop to allow a little more travel on the shifter.
"The shop said it was great". What did they check? I overlooked a bad reverse gear in my brothers ******, had to pull it out and replace it. Did the same thing yours is.