TD20E Tranny Clutch Pressure Droping

[shopguy]

I am working on a 20e that is driving me nuts as i said the clutch pr.is normal cold but when it gets hot 1/2guage the clutch pr.drops to to100 psi, now here is the strange part it does it in all gears and the main pressure holds normal 275psi so iam thinking modulator valve but i have replaced the springs in it and same thing.I have had leaks on sealing rings and clutch piston seals before but never seen a leak inside effect every speed in both directions this way. :Banghead
Thanks for any help.

 

[Iron@Dirt]

Sounds strange, not familiar with a 20. If you bleed off more clutch pressure does the main pressure ever drop off? This would mean restriction between clutch valves and input. A diagram could help. The modulator vavle could be sticking just enough when it heats up, could check for burrs on valve, maybe polish a little, but careful not too much.

 

[.RC.]

I have a TD20E service manual if you need any information

 

[shopguy]

Thanks to both of you i talked to a guy who does a lot of IH and he says the modulator IS the problem,. wear in the bores and on the plungers not weak springs.I have the service manual they sell but you may have a dealer one that is better please look into what yours says about this.
Thanks