Tranny Mod. And tranny itself??

[lnkprksoldier]

Sorry, i know this topic has been discussed to death but i wasn't able to decipher what i needed. When i drive the car cold ( not in temps like 30 degrees farenheit but at like when it is 60 outside and the car was left alone overnight. At the beginning the car runs rough between all shifts. I put it into first ( 2nd then D trick ) the first shift is the roughest, most firm, then it decreases in firmness each shift after. The last is still noticeable. But also on the shift from 3-4 There is also sometimes a flare. Tranny fluid and filter were changed 3k miles ago. To adjust the tranmission modulator, does the car need to be lifted or can i slide under the car? Thanks for your time, and sorry for the repeat. The car is a 1987 300e

[mbshop]

theres more to check. need to see what yer pump pressure is and what the modulator pressure is. need to look at the control adjustments and for vac leaks.

george

[lnkprksoldier]

Originally Posted by mbshop

theres more to check. need to see what yer pump pressure is and what the modulator pressure is. need to look at the control adjustments and for vac leaks.

george

pump pressure? which pump? how do i check what the modulator pressure is? which control adjustments? and i think i have a vacuum leak because i have that similar problem of the doors locking themselves shortly after turning off the car. The problem only appears sporaticaly and not often. Should i just take it to my local indy for him to check it out?

[rschleicher]

george is right that the correct way to do this is with a vacuum gauge, etc. But luckily you have a gas-engine car, where the vacuum for the modulator is a simple engine-vacuum line. If it was a diesel you'd also have to deal with the part that is "creating" the vacuum that is fed to the modulator.

You can at least do a bit of debugging of your symptoms by pulling the vacuum line off of the modulator (should plug the end of the dangling line), and then verifying that you have firm/hard shifts. (No vacuum is equivalent to hard acceleration with firm/hard shifting - high vacuum is equivalent to slow acceleration or letting up on the gas pedal, with smoother/softer shifts.)

If you don't see a change it is possibly an indicator of a failed or leaky modulator. Some people feel that it is possible to adjust the modulator by "feel" - I'm sure if you search the forum you will find a post that talks about turning the little key that is under the rubber dust cap of the modulator. But it is a better idea to have the modulator adjusted by someone with the appropriate gauges, etc.