hi guys i have search hard for a solution to my prob but i cant find what im looking for so here goes.... i have a sc400 auto trans when im driving with o/d off my car rides super smooth but doesnt down shift with the o/d on it thumps or clunks very hard into 3rd gear it seems to downshift as soon as the gear changes. has any had this prob an what was your solution. this only started after i changed out the mufflers an clean throttle body. all 3 new mounts an new tps no change. i drove around the other day with o/d off at about 40mph an hit the o/d button an the thump hit instantly an car downshifted felt like it tried to shread my tires. any ideas would be great please help me other than that this car is awesome

 

whoa . . . deja vu!


I believe if you search here you will find references to tranny shifting issues related to the adjustment of the tps.

 

i have tried every tps setting from .45 -.60 ohms an none of them got rid of the thud. at .53 -.51ohms it shifts really soft but it still thuds just not as hard. i want the thud gone.

 

with O/D OFF your transmission only uses gears 1,2,3

with O/D ON your transmission will use the overdrive gear which is 4. So it will use all gears 1,2,3,4 (O/D).

The thump you're feeling could be caused by many things. Low transmission fluid, the new tps sensor, or the new mounts.

Do you have any check engine lights on, O/D lights flashing, or Trac light on?

 

get a new transmission rubber mount and install new shift solenoids.

$500 - $600aud

toyota type 4 fluid
shift solenoids installed
pan gasket
pan removal and install
labor to do everything

the whole thing takes 1hr max to do on a hoist

 

had two trans flushes toyota type fluid. new filter new rubber mounts. no codes period. the tps is new but would it do this maybe if it was the wrong tps? thanks guys cuz i really want it silk smooth again!

 

where can i find these solenoids an how much do they cost

 

im leaning more towards torque convertor ive tried everything under the sun