T150 issues

Purchased a 79 Cj5 last year, has a 360 swap. Transmission seemed fine, but it would jump out of 2nd gear when decelerating. Clutch pedal was 2" from top and had no more room to adjust. I removed transmission and bell housing, replaced throughout bearing with an adjustable one from Novak...found a very worn 2nd-3rd shifter fork and a bad 1st gear..I replaced both and all 3 synchro blocking rings, front and rear bearings, needle bearings and thrust washers..got it together and installed...
1st test drive and now I have developed a popping sound in 1st and 2nd gear,and still jumps out of 2nd gear ...3rd gear is smooth and quiet...
I am very disappointed, as I thought the shifter fork was the main issue , or blocking rings..
I am thinking maybe replace 2nd gear and 2nd-3rd synchro assembly now ???
Any advice would be greatly appreciated...
I also noticed that the front driveshaft was turning a bit ,in 2WD, as I had left the tunnel cover off for the test run..is that normal ?
Again, any and all help appreciated.