Reverse boost valve and pressure regulator system

[Brooks]

I've been looking at the ATSG manual trying to decipher the pressure regulator system but I'm having a little difficulty.

I understand that the reverse boost valve biases the pressure regulator in rev, 1st and 2nd gears but does the reverse boost valve act on the PR system at any time the transmission is in reverse, 1st or 2nd gears regardless of shifter position or does it only become active if the shifter itself is in the R, 1st, or 2nd positions?

It seems from the diagrams that TV boost would overide the reverse boost valve at larger throttle openings. If that's right, why use the larger reverse boost valve if you have the large (.570) TV boost valve? If that's wrong, please help me understand the relationship betwen the two.

Charles Brooks

 

[chris718]

it adds extra force to keep the valve downshifted when oil is fed to the inner lands of the valve.this is through the reverse circuit apply oil in reverse and the transfer tube in manual lo and second.other times it is pressed on by the tv boost valve and doesnt increase the load that must be overcome to open the valvetrain.

 

[Brooks]

Thanks Chris,

Is the reverse boost valve a kind of intermediate step in increasing pressure? Would I be right in thinking that the reverse boost valve is there to take up the slack so to speak at lower RPM (pump volume), and increase pressure somewhat until the RPM and TV pressure rises enough for the TV boost valve to overide the reverse boost valve and apply full pressure?

Hope you guys don't mind these never ending questions This is my first transmission rebuild and I tend to go overboard when I try new things. I like to understand how things work and why things are done instead of just pushing the ole "I believe" button and moving on.

Charles Brooks

 

[chris718]

it boosts in addition to what is already there.more is needed for reverse and manual shifting.