jesterx888 Posted May 26, 2010 Report Share Posted May 26, 2010 I just replaced my vacuum modulator hoping it might help my trans issue. It is an adjustable modulator so i can adjust it for firmer or smoother shifts. If I adjust it all the way to get the most firm shifts i can, is there any risk of damaging anything? Quote Link to comment Share on other sites More sharing options...
alec_b Posted May 26, 2010 Report Share Posted May 26, 2010 Not really, that's usually what I do when I put the adjustable one in. All you're doing by turning the screw is adjusting the amount of vacuum that's allowed into the modulator. Less vacuum, firmer shift. Unless there's something already wrong with your transmission, you'll be fine. Quote Link to comment Share on other sites More sharing options...
RobertISaar Posted May 26, 2010 Report Share Posted May 26, 2010 if i were you... i would turn the screw to maximum firm, start the car, get it up to temp, put the gear selector in 1st. if you can hear the tranny groaning, you need to back it off a bit. once the tranny quits groaning, then adjust to whatever you like. at least it think that was the recomended method... Quote Link to comment Share on other sites More sharing options...
jesterx888 Posted May 26, 2010 Author Report Share Posted May 26, 2010 Could a bad/misadjusted modulator be a part of not having 4th gear? Quote Link to comment Share on other sites More sharing options...
RobertISaar Posted May 26, 2010 Report Share Posted May 26, 2010 unlikely. the modulator control the amount/rate of pressure/flow the shift solenoids/accumulators deal with. if it was so far mis-adjusted that you couldn't shift into 4th, you would never shift out of any gear. Quote Link to comment Share on other sites More sharing options...
jesterx888 Posted May 27, 2010 Author Report Share Posted May 27, 2010 unlikely. the modulator control the amount/rate of pressure/flow the shift solenoids/accumulators deal with. if it was so far mis-adjusted that you couldn't shift into 4th, you would never shift out of any gear. Didnt think so. And after driving it the problem I have is still the same:think: Quote Link to comment Share on other sites More sharing options...
Galaxie500XL Posted May 27, 2010 Report Share Posted May 27, 2010 Do you have any codes set? I'd almost bet you have a P0740 set...common problem, I've got the same issue with my '95 LQ1 Cutlass. One of the guys here clipped the lead to the PWM solenoid to get the TCC to stop slipping on engagement, with encouraging results...but I've not been that brave yet. If yours behaves like most of them I've seen, when you first take off in the car, you have 4th, but after things warm up, 4th is gone. There is another thread on the list that stated that many times, if the gear selector switch is misaligned, this also can cause a no 4th gear fault. Quote Link to comment Share on other sites More sharing options...
jesterx888 Posted May 29, 2010 Author Report Share Posted May 29, 2010 Do you have any codes set? I'd almost bet you have a P0740 set...common problem, I've got the same issue with my '95 LQ1 Cutlass. One of the guys here clipped the lead to the PWM solenoid to get the TCC to stop slipping on engagement, with encouraging results...but I've not been that brave yet. If yours behaves like most of them I've seen, when you first take off in the car, you have 4th, but after things warm up, 4th is gone. There is another thread on the list that stated that many times, if the gear selector switch is misaligned, this also can cause a no 4th gear fault. How would I check transmission codes? Do I just jump the a and b terminals on the obd1 connector? I did clip the pwm wire and it was not good. It seemed to slip bad when i tried taking off fast and the ses light came on and it didnt help my problem of not having 4th gear. I do have another thread about this problem on here but it seems to have stalled out... Quote Link to comment Share on other sites More sharing options...
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