TH350 not staying in gear?

[matthew_rhodes]

I'm running a th-350 and when I put it in 2nd gear it still tries to shift. Now, in my opinion, when I put it in 2nd it shouldn't shift. Am I correct in thinking this? If so what could be causing it to shift? And if not is there a way to stop it from shifting?
EDIT: I forgot to mention, it's shifting down to first when it shifts. Not up to third.

 

[DRIVEN]

Modulator vacuum hose intact?

 

[matthew_rhodes]

Not hooked up at all. Same with the kick-down cable. A little more info on when it's doing it, it's a circle track trans, when I let off the throttle going into the corner it downshifts to 1st, then I have to slam the gas to get it to upshift again.

 

[DRIVEN]

Is it supposed to be? Is this transmission specifically setup for the track? Has it worked right in the past and developed this problem recently or is it a new setup?

 

[matthew_rhodes]

No it hasn't had a track specific rebuild, waiting for the off season. In the past it's worked ok, but I've never pushed it as hard as I have started to recently. I'll put a vacuum hose on and see next time I'm at the track though.

 

[Pontiac455]

If u put the shift leaver in second it is gonna start off in first and shift to second. It shouldnt go into third until u move the shift leaver. It has to start off in first because if it didn't second gear would be smoked up pretty quick... There is not enough pressure applied to the holding member with a second gear start wich causes clutch slippage then soon after there is no apply friction at all. If it is going from first to second then back to first the faster u go round the track check yer fluid level might be low and the pump might be losing prime whch would lower the line pressure. Also another thing that happens is the the spool valve in the govner becomes sticky. Take it out and clean er with brake clean. They spool valve also wears its bore and hangs up sometimes as well.

 

[matthew_rhodes]

If u put the shift leaver in second it is gonna start off in first and shift to second. It shouldnt go into third until u move the shift leaver. It has to start off in first because if it didn't second gear would be smoked up pretty quick... There is not enough pressure applied to the holding member with a second gear start wich causes clutch slippage then soon after there is no apply friction at all. If it is going from first to second then back to first the faster u go round the track check yer fluid level might be low and the pump might be losing prime whch would lower the line pressure. Also another thing that happens is the the spool valve in the govner becomes sticky. Take it out and clean er with brake clean. They spool valve also wears its bore and hangs up sometimes as well.

I know it starts in first, but I was thinking it shouldn't shift back down to first after that. The fluid was a little low, so I added some. Unfortunately there isn't another practice until July 12th.