First off, did you order up the valve body gasket kit? If you haven't already STOP and get that on order.
The original trans in the jeep was shifting a little sluggish at 230k so I figured why not toss a transgo shift kit in it. In taking it apart all of the wiring was crunchy and crispy from being beaten on for many many many miles without a real trans cooler. I said the hell with it and did the full race car setup on the drilling on the separator plate (Increases shift speed) and with the replacement of the accumulator springs (Controls harshness of shifts). In doing this at WOT it was slam the 1-2 so hard it would bark a set of 33" tires. While cool, this got old over time and within a few hundred miles it would pickup 1st gear between the 3-4 shift, which was interesting and eventually when it would go to lock the torque converter it would also blip 1st gear. I attributed it to the solenoids not being able to hold the higher line pressure, but when I dropped the trans pan it was full of metal and clutch material. I filled it back up with clean fluid and the trans no longer looked for 1st between gears anymore, but I needed a replacement.
Hunting around I scored a unknown possibly blown trans for $50, and upon dropping the pan, the fluid was clean and it wasn't burnt. So I figured why not give it a try. This time I did the hot rod on the 1-2 hole on the separator plate and the full race on the 2-3 hole. Pretty much I made them the same size. I changed the spring in the pressure regulator and did the other valve body mods minus the 1 gear hold shift valve. I also left the accumulator springs factory. This has given me nice crisp shifts without slamming gears and trying to rip the tread off of the tires and at light throttle it shifts pretty close to stock.
RCP Phx
Do you have other gears, just no 1st and reverse? Have to checked the fluid level? Maybe add another quart?