transmission goes bump!

[homer63]

new user here so please be patient and understanding!

i hope this is not a dup thread. i have searched and not found anything to answer (hopefully) my concern. here goes..

i have a '01 corolla with the 1.8 vvt-i and 4 speed auto. i dunno about model numbers as i just purchased the car and am beginning to get accustomed to its underhood options.

when i put the tranny in gear, be it drive or rev, from either park or neutral or shifting drive to reverse or vise versa, it gives a fair bump. the 1-2 shift gives a bump too, but it seems to do okay with the rest of the shifts.

i read in another post about the trans throttle cable so i checked that. pulling on it, it moves freely without any hint of hangin. when i release it i hear a click from the tranny as whatever is in it settles against its stop.

a trans shop suggested i may have a pressure problem. talked about some solenoids and stuff some of which could be serviced in vehicle.

any input would be greatly appreciated as i just got thru with one trans rebuild that cost me $1600! and i felt pretty good about that price!

but i dont want another rebuild if at all possible!

be glad to provide add'l info as needed.

any tranny gurus out there i would greatly appreciate your help!

thanks in advance!

[fishexpo101]

Do you know the history of the car? How well it was maintained, the service interval of the transaxle?

If you hear a "thump" as well as feel it, I would suspect engine/transaxle mounts and/or exceptionallly worn axles to be more likely than an internal transaxle issue. Unless the transaxle has never seen any sort of service (fluid exchange, pan drop, etc.) during its lifetime. The mounts and axles are more likely the culprit, since you notice the "thump/bump" only in the lower gears, where you have higher torque multiplcation - engine is loaded more.

[homer63]

thanks for the reply fishexpo101.

that was another thing i checked. the mounts and throttle cable were the two culprits i checked. mine seem to be fine.

which led me to wonder if there was another typical or inherent problem with these trannys that may be (fingers crossed!) fixed incar.

having just purchased the car i've not changed the fluid/filter yet holding out till i can maybe pinpoint something and avoiding doing the fluid change twice!

maybe the fluid change would affect it?

trans fluid conditioner like sea foam?

[fishexpo101]

I would atleast do a drain and refill on the transaxle. Doesn't hurt, and only takes about 4 quarts of Dexron II/III ATF. If you are feeling adventurous, do a pan drop and note the amount of metal power/shavings in the bottom of the pan and what is stuck on the pan magnets. Filter change would also be adviseable, if you pull the pan - through you could just clean the old filter (more of a screen than an actual filter).

Do simple maintenance first, before you start adding additives and whatnot. Those tend to mask the problems/symptoms - you really want to find out what is going on first, before you treat it. Don't want this to potentially end up as a large repair item down the road. I've noted that my transaxles always seem to shift a little differently (smoother) after some fresh fluid is introduced - even from a simple drain and refill.

As for Seafoam trans-fluid additive, I've heard pretty decent results with it, but most have noted that it took some time before it did anything (usually after the second or third ATF fluid exchange).

[homer63]

agree with you on the additives! im not at the brake fluid additive yet!

got the fluid/filter change completed yesterday. fluid came out dark tho not black. didnt have the atf "stink" like the fresh fluid. pan was clean of debris. only had a thin film of gray sludge or mud as i like to call it. had 2 magnets. a small amount of sludge around them. metal particles were so small as to be imperceptable. so overall it was a very promising sign.

i could see some matter in the filter screen tho it was very small particles. the screen was not covered completely so i dont think the filter was causing any blockage. it looked pretty good actually.

replaced the cork gasket with a rubber one from the auto zone kit, tightened all down to 48inch pounds.

added syth blend dexron III fluid.

also did a brief flush by disconnecting the output line from the cooler.

disconnected the line and ran the motor for about 15-20 seconds maybe at most. dont know how much good it did, but hopefully it flushed some of the old fluid out from the converter and cooler.

topped it all off and added about a half pint of sea foam.

drove it today. it seemed not to help much with the bump. but i feel better that it has at least some fresh fluid.

it was a good note you made that the sea foam will take time to work. if it is sticking parts i can see that it will take a bit for them to work themselves loose. if it starts to improve i may do another fluid change and additive.

if i left out anything let me know.

the saga continues!

thanks for your very much valued input!

[homer63]

well, it has its moments. it will shift softly after the motor warms up some but still it is harder than i would consider normal.

does anyone know how i might go about checking fluid pressures?

mike

[homer63]

ok. so this is an on going problem that i have been researching on the web and using personal contacts.

there are several things that consistantly come about.

check the fluid condition and replace the fluid/filter.

that i did.

the other is checking adjustments.

so i check my tv cable. the most obvious thing. it is an odd setup i think. i should have a long rubber cover over the end of the cable end so when the throttle is fully depressed i have one mill of the lead stop exposed beyond it.

well the cover i have is only about a quarter inch long. hmm. how to check that!

so i go to the local pull a part and find a car with the rubber part that is correct and take a measurement and head back.

using the measurement i find my cable is stopping short. so i make the necessary adjustment.

wala! i have smooth shifts from neutral to drive! my gosh!

it is like a whole nother tranny.

shifts from neutral to drive are almost unfelt. driving it, the shifts are much smoother. at slightly higher rpm, as expected. and the car seems to have more power which i attribute to the tranny pressure being higher and holding the clutch packs firmer. mebbe?

but it is a definite improvement. i am tickled to say the least.

what appears to have happened is over time the tv cable has stretched causing the pressure to drop in the tranny. the tech i took it to said it was a hesitation which i could see being attributed to low pressure.

adjusting the tv cable brought pressures back up to "normal" and the trans is operating much better.

so the moral of the story, if you have a older tranny acting silly, be sure to check that tv cable as part of your diagnosis. i made a very small adjustment and got big results.

smiling!

mike

[Steve40th]

Originally Posted by homer63

ok. so this is an on going problem that i have been researching on the web and using personal contacts.

there are several things that consistantly come about.

check the fluid condition and replace the fluid/filter.

that i did.

the other is checking adjustments.

so i check my tv cable. the most obvious thing. it is an odd setup i think. i should have a long rubber cover over the end of the cable end so when the throttle is fully depressed i have one mill of the lead stop exposed beyond it.

well the cover i have is only about a quarter inch long. hmm. how to check that!

so i go to the local pull a part and find a car with the rubber part that is correct and take a measurement and head back.

using the measurement i find my cable is stopping short. so i make the necessary adjustment.

wala! i have smooth shifts from neutral to drive! my gosh!

it is like a whole nother tranny.

shifts from neutral to drive are almost unfelt. driving it, the shifts are much smoother. at slightly higher rpm, as expected. and the car seems to have more power which i attribute to the tranny pressure being higher and holding the clutch packs firmer. mebbe?

but it is a definite improvement. i am tickled to say the least.

what appears to have happened is over time the tv cable has stretched causing the pressure to drop in the tranny. the tech i took it to said it was a hesitation which i could see being attributed to low pressure.

adjusting the tv cable brought pressures back up to "normal" and the trans is operating much better.

so the moral of the story, if you have a older tranny acting silly, be sure to check that tv cable as part of your diagnosis. i made a very small adjustment and got big results.

smiling!

mike

Can you post a pic showing how/where u adjusted. I just noticed mine is stretched at 92kimiles, so i am sure tv cable is loose