99 Dodge Ram 4x2 46RE Transmission help

99 Dodge Pickup. Just did a complete trans rebuild with new torque converter. (Reverse went out) After completion, the tran would shift from first to second then back into first. I replaced the speed sensor and the governor selonoid. Test drove and worked great. Shut it off and when I tried it again, it was slipping in reverse. I checked and reinstalled the reverse servo. Reverse works great BUT now it is doing the same thing with the shifting from 1st to 2nd then right back to first. I am at a loss. Any help would be great!