2004R 1st gear problem

[Malibutomi]

Ok guys heres my problem,hope one of you can help me.
My 2004R is assembled with alto bands and clutches, a superior pump, CKperformance valve body (#24RVB/RK), billet servo and so on.
It shift firm, chirps the tires in 1-2-3 shifts...but not all times..becouse...
The tranny only has 1 gear when it gets hot...15-20 mins in downtown traffic jam....or a few circles on WOT, or burnout...so when its get hot..suddenly theres 1st gear...
In normal use, sit in-start up-drive the car starts in 2nd gear, shifts 3rd and 4th good.If i put it in 1st with the shifter this time, it feels something like when i left the parking brake on...the car dont want to roll easy...
If i shift 2nd it feels normal.
If the tranny is hot i can shift 1st gear manually, and it works. What can this be?
I have an external tranny cooler, and an aftermarket aluminum radiator, so the tranny lines not going into the radiator, only in the external cooler.

 

[Lee Thompson]

My guess is

One of the scarf cut sealing rings on the forward drum shaft has been damaged during assembly. If so, I believe it will do the same thing in reverse. Happened to me once. Try backing off the TV cable adj. 2-3 clicks--could solve the 1st gear starts. I'm sure some of the others can help. Best of luck.

 

[Malibutomi]

Reverse works fine. But i'll try to adjust the TV...nothing to loose