car doesnt like 50km/h

[Matt]

2001 corolla auto, if i travel at 50km/h the car seems like it cant decide what gear to be in? or thats how i perceive it?

It will gain revs ~2000rpm, then i feel the gears change (atleast i think they have) and then the revs drop and keep going down to below 900rpm as the car slows a little, then i feel it kick back (bounce) gears and back to 2000rpm

im stumped because if i hit overdrive off (force to 3rd gear?) it still does it!? and if i shift to 2nd gear it revs even higher?! (~2500-2600rpm) – not quite sure whats going on but i dont want to ignore it if its something vital

i also noticed its only when the car is hot (normal operating temperature), and also when im slowing down or pulling up to a stop before the car wants to stop it seems to kick slightly or not want to slow down until im nearly at a stop before it backs off (not too bad but noticeable as if i have to use my breaks more then i should) — its otherwise not too bad, its not overly rough/hard while shifting

i have had the transmission fluid changed ~15000km ago and its still clear/red colour, the mechanic did tell me the old fluid was black (not sure if he ment dark/bad or black black)

also the car has done 175,000km

any help or suggestions? thank you in advance!

Topic

[Sheldon]

If your trasmission fluid was black that is not good. You will need a trasmission repaired.

[NissanMaxx]

OK well the transmission fluid is not the issue so lets get that out of the way. If your car cant decide what gear its in then it could possibly be a bad speed sensor. I would check the wiring of your speed sensor and to find this sensor just check around where the axle goes in on the transmission.

[EricTheCarGuy]

I often get questions about changing transmission fluid after a long period of time and the truth is it’s a roll of the dice. Sometimes you can change the fluid and things will be just fine. Other times you change the fluid and the transmission will fail shortly afterward. I fear that you may be in the ladder category and I would suggest you have your transmission checked.

[college man]

when you had the fluid changed.was a machine used?

[Matt]

not too sure it was a while back, ill check the receipt when i get a chance, i’m sure it was “flushed” if that helps

everything still works aok like it never slips or harsly moved or anything but id rather get opinions and ideas rather then just ignore it and find out i should have had something done etc

should i try some auto transmission additive?

[college man]

here is a video that might help. check the transmission
kick down cable.see if the cable operates smooth.
Do you have any check engine lights on?

[Matt]

thanks for the video ill check that shortly and let you know

no warning lights at all, but i am experiencing something else – my other post (http://ericthecarguy.com/main-forum/8-Service-and-Repair-Questions-Answered-Here/34216-low-idle-speed-randomly-when-hot)

i separated the two questions out because i dont think there related?

[EricTheCarGuy]

It’s not likely anyone did any adjusting of the kick down and if that was at issue it would effect shifting with ALL gears not just one. To me it sounds like you have a clutch that’s worn out and the only way to repair that is to overhaul the transmission, it’s not likely additives will solve the problem.

[Matt]

problem solved

both my problems were related (http://www.ericthecarguy.com/component/kunena/8-Service-and-Repair-Questions-Answered-Here/34216-low-idle-speed-randomly-when-hot)

solution (http://wiki.answers.com/Q/How_do_you_adjust_idle_for_Toyota_paseo)

Idle base line set too low, once the car warms up the IAC closes up which drops the revs to the base speed which was set far too low, when i got the car the IAC was jammed half open, (hot idle too high, cold idle too low) the old owner or last mechanic would have just set the idle lower (fix high idle when hot) rather then take out and clean the IAC, after i clean the IAC it resulted in the low idle set by them.

Now the car idles (cold) 1100rpm, and warm ~850-900rpm, aircon on = ~900rpm still.

When shifting from 3rd to 4th because the idle base line was so low it would panic dipping below 1000 (from low idle) and switch back to 3rd, with the idle set higher it has enough power to keep 4th at 50km/h.

Thankyou for all your help and suggestions.

[college man]

Thanks for the update and the fix.

[EricTheCarGuy]

That’s an interesting fix thanks for posting it and for using the ETCG forum.

[Matt]

Update

I checked out all the vacuum lines, PCV and Charcoal Canister – the PCV wasn’t sealing properly (sticky valve, allowed air in both directions) and the Charcoal Canister valve (line to fuel tank) was very sticky requiring a lot of pressure to open.

Throttle body cleaner on the PCV till it moved freely and same on the Charcoal Canister (while holding it upside down to make sure the fluid wouldn’t go into it) then compressed air and now that valve works a lot better (might replace it soon however).

After all this and dropping the Idle down to factory standard my problems have gone away while maintaining the low idle speeds (hopping when pulling up when the transmissions changes to first, maintaining 50km/h).

My other car (2000 Toyota Camry) also idles low when warm to i take it its a Toyota thing, didnt want to stray of the standard design spec if there ment to be like that etc.

Seems my Corolla relies heavily on these systems to run smoothly!

Thought i would update you guys on the progress in case anyone else out there is having the same minor issues.

[Author]

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