any way to make a 400 stay in 1st til you shift it
to 2nd ???
the trans is a 74 from a 1 ton chev truck,I am running a 2500 stall(B&M HOLE SHOT)and shift kit.

I have the trans all apart a now would be the time to do any mods!

thanks!

First, do you have the detent (kickdown) switch hooked up. TH350's used a cable, but the 400's use an electric solenoid on the tranny that gets wired to a switch at the gas pedal or the carb linkage. You can buy adjustable aftermarket switches. If that's OK I think you can change weights and springs in the governor so it shifts up at a higher rpm. If all else fails you can put a manual valve body in the tranny but they can be a pain on the street.

I believe it requires a valve body modification. Kick down solenoid is a good item to check though. I think the shift valve is made such that once govenor pressure reaches a certain point the shift valve will go ahead and toggle. The feature has always been referred to as "panic shift" and I'm sure someone out there knows if there is a shift kit or VB mod to fix it. I would guess it involves blocking a passage in the separator plate or installing a new shift valve.

-dnult

Dnult is 100% correct. You need to get into the valve body to do it. smile.gif

actually all that is needed is to block one hole in the valve body casting and grinding a relief in the 1-2 shift valve. This will hold 1st gear till you move the shifter.

It will require removal of the vlave body from the tranny and some gaskets.

I have a B&M rebuild kit that had a valve to change in the VB but didn't say why,it also said that if they're vavle was a different size to grind a 1/2" flat on the orginal valve.

also does the modulator or governer control a rmp of the shift point ???

thanks I'll be going to the B&M SITE FOR MORE INFO.

thanks!

Governor circuit pressure acts on the shift valves along with modulator pressure, against the 1-2 and 2-3 shift valve springs, to determine the shift timing. The detent pressure acts on the shift valves and dumps its pressure to downshift, through the solenoid.