replaces tourqe conveter and front seal and bushing now i have sfiting problem

[wimpytwins]

i have about 70,000 miles on a rebuild a4ld tranny. they front off the tranning was leaking fuild out as fast as it would go in so i pulled it out had a shop replaced the bushing and front seal and align it all up. when i opened it up to take of the front to take it to the shop the tranny looked like brand new. i didnt disasemble it at all but there was'nt any bunrned or build up of fluid or clutch plate material. i also droped the pan and relaced the filter.the bottom of the pan had a very layer of clutch plate material that wiped off with a single wipe.it though that wasnt bad for a rebuild tranny with 70,000 on it. i also bought a new tourqe converter. as i was putiing it back together i turned a knob on accident and found out it was a after market adjustale vancume modulator. i filled up the tranny with micron/decron 3.
now when ever i put it in reverse if i gas it a lot of gas the whole truck shakes. if a granny peddel it it works fine. in the forward gears it shifts though all the gears by the time it get to 30-35mph. i also can feel it slipping threw all of the gears. again if i put my foot down from a dead stop it will do up fine to about 10-15mph and then start to shift and slip bad until it gets into drive(i put the shifter into drive not over drive.) it works great after that. i can get on the freeway and no slipping i can also go into overdrive with no slipping. if i manually shift threw the gears my self there is no slipping when it shifts or once it is in gear. i have never had any problem before with my tranny and even when it was leking fluid pretty bad it still worked great. i have been slowly turning the vacume modulator in both directions and it just seams to make everything worse. can the vacume modulator cause all of my problems? what the hell is did i do?
thanks bryan

 

[tankmech]

The vccume modulator controls the line pressure in transmission and can cause all of those problems. They do not come preset as each transmission is different due to wear and tolerances. The best thing you can do aside from taking it to a shop is buy the manual and follow the adjustments for it. There are also different modulators. They are marked with a color either a ring around it or the nipple where the hose is attached. Make sure that you have the right shift modulator.

 

[Glacier991]

well. with all due respect...actually line pressure is not controlled by the modulator. The pressure regulator controls line pressure (ok and the boost valve plays a part here too). The vacuum modulator controls throttle valve (tv) pressure, which provides the necessary pressures to control when shifts occur, by modulating presures in various shift valves, often counteracting line presssures.

I need to know what all you did in that trannie. Did you remove the valve body? (moving the modulator screw in or out should only affect timing of shifts...) Something does not sound good. I need more info.

Any access to a trans pressure gauge? Your reverse shudder is odd....

 

[wimpytwins]

thank you for the help. i pull the tranny out with the transfercase attached. i never unbolted the transfercase from the n trans. i unbolted the front houseing(pump) and took it down to the trans shop and they put in a new bushing and front seal. i didnt touch anything inside the trans. after i got the pump back i bolted it back on. i put on a new gasket and new orings on the bolts. after that i slid on the toruqte converter and i made sure i did it right. they told me at the shop that when i put the trans in the toruqte converter should have a little bit of play and shoul not be jammed up against the flywheel. i didnt have any jamming problems. once it was in a took off the trans pan and drained the fluid and replaced the filter. the filter was kind of wierd and it seemed to fit as well as the old one(now that i think about it). then i put the trans pan back on and and filled it if dexron/mexron 3 (i think i spelled it wrong). i have allways top if off in the past with type f fluid so i dont know if useing the dexron 3 could make a difference. when i shift it mormally i let it rev up to about 3000rpm before i shift. i dont know if the filter might be the problem and all it needs is enough rpm to get the pump to move enough fluid with a leaky fillter. would it still slip when i gun it when i am in regular drive and the rpm are around 2500-3000 and then they shoot up to 4000-4500 and it still slips on the down shift and then coninued slipping untill it finally gose into drive or i fet off the gas. i know that on the drivers side of the transmision there are two adjustment blots that adjust the bands inside and after i put it together and found out it was haveing problems i tightend them both up about a half a turn. i notice that it help it shift stronger into drive but thothing else. i also have tryed to reset the car computer a few times and that did nothing. could it be a pump problem that the trans shop did? could it be the fuild, could it be the filter? but i would think that if the rpms were already up it could down shift with out a problem even though the filter isnt tight. should i over fill the trans and see if that fets it get enough fluid. there are no leaks at all from the trans. should i relace the adjustable modulator with a stock modulator. i never touched the vavle body or anything like that. i am willing to try anything so just tell me what to do. thanks again for all of the help.

 

[Glacier991]

I am going to assume you have checked the fluid at idle and you have adequate fluid. That being the case, my guess is either the filter lacks O ring seals or is improperly installed; or, the pump is somehow at fault. Buy a FRAM microfelt filter. Make sure you use the correct mounting bolt and make sure you have the O rings on the filter's two little "snouts". Refill the transmission to the proper level. Check that level with the engine running. If that does not fix it, I'm suspecting the fromt pump somehow. I'd like to know line pressures.

 

[wimpytwins]

thanks i will give it a try this weekend and see what happens. again thank you for all of your help.