update on late shifts

[broncobuckinaround]

now that i have gotten the modulator back in. all new hoses.

now it shifts between 2000-3000 rpms with a medium pedal id say 30%
is this normal. or does it need some more adjusting and if it does how do you do it. i know there is a allen head for a screw like thingy on it. do you turn it to adjust it.

not sure. any help is appreciated

 

[PetesPonies]

If it has an adjustable modulator, yes turning the screw will change the shift points. You want to do it in small increments. I would back the screw out 1/2 turn and see what that does for you.

 

[kimcrwbr1]

Turn it one full turn at a time and watch the speedometer not the tach. With light throttle pressure you want it to shift around 13 mph 1st to 2nd and into 3rd between 20-25 mp with light throttle pressure. The harder you push on the skinny pedal the later the shift will be. The book say adjust/diagnose it with light pressure. If the modulator dont do it it may have valve body problems. The only way to diagnose it further is to put a oil pressure guage on it and check the control pressures with vacuum pressures. Have you checked your manifold vacuum pressures?

 

[broncobuckinaround]

i havent yet checked it with a vac gauge but verified its got pressure. and i made sure to pull off the connector for all the lines and checked for any kind of blockage. both were clean and free of anything.

haha cops came by last night and told me to i could drive it on the streets anymore due to no tags.

so in about a week after i get it tagged and insured ill complete more tests.

 

[PetesPonies]

The adjustments you make to the modulator will effect internal line pressure. For that reason I'd rather see you adjust it 1/2 turn at a time.

 

[kimcrwbr1]

I was told 1 full turn at a time and fine tune when you get close. All it does is change spring pressure on the diaphram. The more spring pressure (clockwise) the later the upshifts and less spring pressure (CCW) the earlier the upshifts.

 

[PetesPonies]

All it does is change spring pressure on the diaphram

And there is where you are missing some information. In the valve operation itself, vacuum is pulling against a spring; yes . . but the final verdict of what is going on is transmission line pressure is changed. This happens inside the valve body which is what the modulator valve is controlling.

 

[broncobuckinaround]

thank you both for helping me. im getting a lot of info. and it sounds as if we both are getting a lesson on this mater.

ill adjust 1/2 turns in adjustments and see what happens. it will have to wait til i get it licensed cause the cops keep driving by to make sure im not driving it. ill log this info in my brain and remember it just be for i leave for the break in period.

i thank you both again for the help and i will write again when i have the next update.

 

[kimcrwbr1]

And there is where you are missing some information. In the valve operation itself, vacuum is pulling against a spring; yes . . but the final verdict of what is going on is transmission line pressure is changed. This happens inside the valve body which is what the modulator valve is controlling.

There are actually three pressures the modulater does business with control pressure, throttle pressure and boosted throttle pressure. There is no line pressure in a automatic transmission according to my book. There is a cooling line and return line that forces the cooled oil on the main bearings/bushings in the housings.

 

[PetesPonies]

Wow . . not going by a book here and you are sadly mistaken. That's what happens though as you read and try to make sense of it all. Ask a trans tech about "line" pressure. or do some web searching.

 

[broncobuckinaround]

kim i do believe pete is right. i dont know when they added a line pressure solenoid into automatic transmission. but a lot of them should have pressure solenoid. because how else are they going to get an adjusting pressure with a electric or mechanical piece. cause i dont imagine a trans can make its own pressure.

kinda like the pistons in a an engine make oil pressure.

lol i guess

 

[PetesPonies]

Here's a Google definition :

An automatic transmission line pressure control system controls line pressure in an automatic transmission equipped with a torque convertor for hydraulically coupling and uncoupling friction coupling elements of the automatic transmission. The automatic transmission line pressure control system regulates line pressure for selectively coupling and uncoupling the friction coupling elements so as to shift the automatic transmission into desired speed gears. The line pressure is forcibly dropped to a level lower than a level present before an occurrence of a manual shift-down operation when a shift-down sensor detects the occurrence of a manual shift-down. The line pressure is then raised as a speed sensor detects an increase in rotational speed transmitted the automatic transmission, thereby shifting the automatic transmission into desired speed gears.

 

[kimcrwbr1]

Here's a Google definition :

An automatic transmission line pressure control system controls line pressure in an automatic transmission equipped with a torque convertor for hydraulically coupling and uncoupling friction coupling elements of the automatic transmission. The automatic transmission line pressure control system regulates line pressure for selectively coupling and uncoupling the friction coupling elements so as to shift the automatic transmission into desired speed gears. The line pressure is forcibly dropped to a level lower than a level present before an occurrence of a manual shift-down operation when a shift-down sensor detects the occurrence of a manual shift-down. The line pressure is then raised as a speed sensor detects an increase in rotational speed transmitted the automatic transmission, thereby shifting the automatic transmission into desired speed gears.

You didnt happen to notice that all of those shift points are electronically controlled with sensors and servos that regulate control pressure and is programmable with the ecm. The A4LD has a modulator and a govenor to deetermine shift points?

 

[kimcrwbr1]

By the way control pressure is line pressure.

 

[PetesPonies]

Kim . . I'm trying to help you out here. Whether or not a trans is electronically controlled hydraulic pressure or not, they STILL have line pressures. This just basic Auto Trans 101. I can't be more simple and direct than that. Rather than trying to prove me wrong ( which I am not . . remember ex teacher here ) you should research to learn.