harder shifting after tranny service
 

i had posted this before under "transmission shudders". anyway, after my recent tranny service about 800 miles ago, i noticed that the shifts were harder. the 3-4 shift in particular is harsh particularly at lower engine speeds. i would characterize it as a slight shudder. the fluid i used was valvoline semi-synthetic. while i am wary of synthetics and leaks, i decided to give it a try with the thought that the synthetic portion would help "clean out" the tranny. i was planning to drain then refill with dino ATF after 12k or so but i may want to do this sooner if i don't get rid of the shudder. i have checked the fluid level and it is correct. will lowering the pressure on the vacuum modulator help? if so, how much should it be turned?

thanks

How many miles on the transmission ??

the transmission was installed about 20k miles ago. i am assuming it is an MB reman'd unit. it was replaced under warranty by a dealership as the old one was DOA "no forward motion" indicated on the report. i suspect that the new tranny was never set up properly. the car was literally "grandma's ride around town" and i doubt the PO would have complained about anything. i acquired the car almost 2 months ago and have been going through a list of maintenance items. i replaced all the fluids as a matter of course. shift quality was ok prior to the service although i was not happy with shift points (another thread)...

Be sure that there is vacuum in the plastic line going to the modulator. Try sucking on the modulator to be sure that has a tight diaphram.

If all is well then I would try adjusting the modulator. I am interpreting your condition to be hard shifting. I get a bit confused because this can actually be the opposite of "shuddering". I describe shuddering as a multiple shift where one gear change appears to be accomplished through multiple steps. For a harsh single shift I would start with a full turn counterclockwise.

If there is a shudder as I described it then you will probably need to make the shift firmer or possibly earlier.

first, the hard shifting: turns out i don't have to mess with the vacuum modulator, at least for now. by adjusting the bowden cable to make it shift later i seem to have eliminated the problem. the low shift point (~2k rpm) was making the shifts harsh. now the shifts are a lot smoother.

Steve, i will make another thread on shift points as none of the adjustments i made seem to have affected full throttle/kickdown shifting. the shift quality did improve with the bowden adjustments but i am stumped with the max shift point.