no i dont have a tach but i was thinking about getting one...are they easy to install? i like where its shifting right now it just has a little pull to it
Yeah I tkink they are relatively easy to install, just follow the install directions that come with it. If you are happy with where its shifting then I'd leave it where its at.
You adjust it by MINIMUM shift points. With the engine warmed up, apply minmum throttle and see where it is shifting. 1-2, should be 9-12 MPH, 2-3, should be 20-25 MPH.. The modulator will only adjust for about 5 MPH at most. High RPM shifting (WOT) requires governor adjustments.
it was shifting from 2-3 at about 40 before i put in the new modulator, i adjusted the modulator little by little. Now it is shifting at about 28 or 30. but i think thats the lowest the modulator can go cause the screw is basically all the way out
Not in my case, when I adjust mine around it makes a huge difference where it shifts and the governor makes no difference. As far as where it should shift I go by where I think a car like ours should shift at and nothing else. Been in the same spot for about 15 years now and it shifts as good as the day I put er in the car and no problems whatsoever with the tranny. A nice crisp fast shift is what you want.
The modulator adjustment will affect part throttle and minimum throttle shift points. Minimum throttle shifts can be raised or lowered 2-5 MPH. The part throttle shift points may be raised or lowered more than that, but not by much. If the transmission is short shifting at WOT, then the governor must be modified. That's my experience, but if your way works for you, I couldn't be happier.
i dont know what you mean by crisp but mine has a little hop that it gives when it shifts that i kind of like...not really like i have a choice though...i cant adjust it any lower
The minimum throttle shift points will vary according to rear axle ratio. A lower numerical ratio will make for later minimum throttle shifts. I'm talking like almost coasting with almost no throttle opening. It should shift to 2nd at about 10 MPH, and 3rd at about 20 MPH. Be careful with the modulator adjustment. Turning the screw all the way out or too much can lower modulator pressure, and line pressure and cause slipping. If I was you, I'd take the car to a transmission shop and have it evaluated. I'm surprised that there isn't an experienced Buick guy in your area that hasn't offered to help you out. Are there no Board members in California close to you?
ive tried posting things on here asking if anyone is around that can help. im in cen cal...pretty much everyone else is either north or south
if it makes it there :grin: yeah i think you might be right. im getting the timing and dwell checked today anyway so i might as well go by the tranny shop too...
I used to have a T400 in my 70 that had the modulator with the red line on it and I remember it made a good bit of difference in the RPM/speed it shifted at when I adjusted that little screw inside it back and forth....the rear end was/is a 2.93.....I think that modulator with the red line on it is a Hi Performance modulator if I remember correctly and is made to make a large difference in the RPM /speed the T400 shifts @....its a moot point now as I went the 700R4 route a few months ago and will never go back to a non-overdrive set-up if I can help it....
i came to a revelation last night as i was just sitting and thinking... i just replaced the intake manifold and if it needs to be retorqued because its loose than thats why my car is having all these odd running problems and this revving problem because if the manifold is loose that means it is losing vacuum and therefore the modulator wouldnt be getting the full vacuum making it not shift right. good theory?
Interesting, as I retorqued my manifold awhile ago just in case it had loosened up. It ran fine but I figured I would do it just to make sure the bolts we're where they should be. We'll now I have problems. My engine rpm drops to much from park to drive. Doesn't idle as well as it used to. Also my plugs are a bit white now. I suspect a vacuum leak some where but can't find it. Sorry not trying to hi-jack your thread but be careful with those manifold bolts. Might end up creating more problems. I was told you can use propane to help find a manifold vacuum leak. Maybe worth a shot first. John Biggs.
Propane can be used the same way as carburetor cleaner, just get a steady flow and spray it at where you think the leak is. If the idle changes drastically (probably smoothing out) then you know thats a leak. Make sure to check all the easy things first, cracked/disconnected vacuum lines etc.
