Re: Turbo 400 experts please step in....
 

Some how I thought your post was to set the shift points at WOT . It is harder to set the part throttle shift points . The modulator system basically makes a pressure to tell the transmission what load is on the engine . This is based on manifold vacuum . The lower the vacuum the higher this modulator pressure would be . So if you have an engine with high vacuum at idle , and you lightly drive away from a stop , you get a very low modulator pressure and therefore a early shift point . A hot rod engine might have a fairly low idle vacuum and if you did that light throttle drive away , you might get a delayed shift . So most hot rodders put a high stall converter in place of the stock tight converter , and what happens is the manifold vacuum is much higher than it would normally be , creating a low modulator pressure and an early shift . Most of the newer transmissions that are built now have electronically controlled shift patterns . They don't shift based on manifold vacuum . Before electronics there were cable controlled transmissions , like the 200 THM or 700-R4 . There were many different modulators to deal with different engines , with different manifold vacuums , but not anymore . The adjustable modulators are really not for you to adjust , but to set the modulator to a factor specification . There is not much you can do with your current vacuum modulator system . One thing you might try is a B&M Modulink , which basically converts the vacuum modulator to a throttle cable controlled modulator . I worked on a similar system for the Hummer , which was a diesel , so no manifold vacuum .

Re: Turbo 400 experts please step in....
 

Check the vacuum at the intake as well. It’s been a while , but from my training during GM tech school, govenor pressure overcomes modulator pressure to make the shift. Someone correct me if I’m wrong, but I don’t think disconnecting the downshift solenoid will have any effect on shift timing.

Re: Turbo 400 experts please step in....
 

X2, I agree.

Re: Turbo 400 experts please step in....
 

Thanks , your friend was correct., you know your stuff..........yes this is about "part throttle" shifts.

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Sorry for the confusion. The reference to the solenoid was about whether I can leave it disconnected and if that has any consequence . No connection to upshift timing.

Re: Turbo 400 experts please step in....
 

The solenoid will delay the upshifts past the 0 vacuum shift point. You can leave it disconnected as the line pressure is controlled by the modulator only but you will get early full throttle upshifts and no kickdown.

Jim Mantle

Re: Turbo 400 experts please step in....
 

Joe, It's hooked to a n/o switch that only passes 12v at WOT, so ,about 99 % of the time, it's not doing anything anyway. So yes , you can leave it unhooked.

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OK , thanks everyone for your contributions.

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Thinking about this a bit more . The kits you can buy just modify the secondary weights and springs of the governor . Your problem is at slower speeds that may be affected by the Primary governor weights , this is the heavier weight . I would look for a different governor that has a Lighter primary weight . Suggest you find one with a big hole drilled through the primary weight and swap it on to your existing governor . Reuse the secondary weights and springs you already have but swap on a pair of the lighter primary weights . See what the effect is to that change is . Some trans shops have used governors you may be able to purchase cheap , and maybe even the pins . We had many , many different governor weights designed , both primary and secondary . Good luck ! BTW when you adjusted the modulator , did you see any effect ?

Re: Turbo 400 experts please step in....
 

Also , you can use some T350 governor parts .Weights, springs. The top is different and the plastic gear turns the opposite way.