T-14 Kicking Out Of 2nd And 3rd

We have completed a rebuild on a 1971 CJ5 v-6 (225) w/ a T14 tranny. The transmission shifts smoothly and can feel the shifter lock into each of the indents on the shifter rails. When we shift from 1st to 2nd the transmission does not want to stay in gear with a load on it and when we shift from 2nd to 3rd it doesn't want to stay in gear either. What is going on? Did we miss something ?

 

Sounds like the transmission output shaft is moving forward and back. Or the 2/3 synchronizer assembly is worn out.

 

All new synchronizers and bearings and lower cluster gear assembly and misc parts. Will check output shaft, but snap ring and front cover holds it in place.

 

When you say synchronizers were replaced are you talked by about the blocking rings or the whole synchronizer assembly.
I said output shaft not input shaft. Output shaft is not controlled by the front bearing retainer.

 

Blocking rings, thrust washers all bearing were replaced. I will check on output shaft movement. If I remember correctly a spacer/shims can be made to put into the rear of the output shaft to get rid of any back and forth movement. Is that correct?

 

Also check the transfer case input gear nut. If loose it can allow the transmission output shaft to walk forward and back causing an issue. If you have to shim the shaft then something is most likely worn. Also when checking the endplay the transfer case input gear and nut must be tight or you will get false readings on the output shaft endplay.

 

Isnt there a 1/4+/- shim needed between the bull gear and the rear bearing on the trans?

 

Yes, a spacer just like you describe. These can become worn thinner than they should be. Usually caused by the transfer case input gear nut getting a little loose allowing the gear to rotate back and forth on the shaft. Also if the splines are worn the same thing can happen even if the nut is tight. Not real common but have seen it happen on a couple occasions.