OK, after tinkering with my truck today, I now think that my modular valve needs adjusting. It shifts real hard going into first gear when coming to a complete stop. Also, when I turn onto a road (for example) and I give it the gas, the truck will hesitate slightly, then the truck will act like it downshifts and it will just take off. Has anyone ever experienced this? My question is, which way do I turn the adjustment screw in the modular valve to correct this problem?

 

i'm not sure the problem is your vacuum modulator.

but- to adjust it...turn clockwise for higher shift point, counterclockwise for lower shift point.

to the best of my knowledge...that's all the valve does- alter the rpm at which the transmission shifts. (that's why i think the valve isn't the problem here.)

 

Maybe not, Im just trying to dial everything in.

 

W-W, When you remove the vacuum hose from the modulator is there any transmisson fluid leaking out of the vacuum port ? If so get a new valve. Also measure the vacuum at the end of the hose and also where the hose connects to the manifold, some times these hoses will collapse. Try bypassing it with a new hose. Also make sure that the downshift rod from the carbureater to the transmisson is free and not binding.