Our 8 year old Fortuner is running pretty well all in all.

However it recently developed an issue that's very intermittent. Eg. most of the time, reverse gear works just fine.

But sometimes, when I put it in reverse, the car shakes and buckles as if the transmission wasn't fully disengaged when holding down the brake. If I keep on the brake for something like 10 seconds, things will settle down and it'll be back to normal.

We gave it to Toyota but they diagnosed a totally different problem with the engine that... I don't think we have. The engine is fine. It works, it sounds normal, there is no smoke, highway performance is same as always. So I think they couldn't reproduce the transmission shaking and went to find something else...

I noticed two things when the problem happens:

- It always happens when I start the car but it's still warm. Never happens from a cold start.

- When it happens engine idle speed is low, like 500 RPM, instead of 800

I don't know if either of these are directly related to the issue. Transmission fluid looks normal and it's at a the recommended level.

Mainly posting here to see if others had a similar issue or if it's anything that is known about the Fortuner.

I am probably out of line.........On old autos first and reverse used the same gear, just diverted fluid to reverse.

BUT, engine computer should retain the idle of about 8/900 rpm, if it is below then perhaps the trans oil pump is not, does not have enough power. Soooooo, idle rpm is your prob.

Is the transmission electronically controlled ? Either stand-alone ECU or as part of the engine ECU ?

Is the transmission electronically controlled ? Either stand-alone ECU or as part of the engine ECU ?

Um - absolutely no clue, sorry.

I am probably out of line.........On old autos first and reverse used the same gear, just diverted fluid to reverse.

BUT, engine computer should retain the idle of about 8/900 rpm, if it is below then perhaps the trans oil pump is not, does not have enough power. Soooooo, idle rpm is your prob.

Interesting info, thank you. Idle speed is usually around 800, I only noticed that when the problem happened last time, it was well below that.

Transam....think it is an A/T....OP have you had the car serviced at anyplace like Bquick....if so check what type of fluid they might have put in....probably does have a TCU...BUT almost sounds like a pump or TQ concern.....is it parked on an angle? Make sure fluid is correct and full...might be a good time to have it drained/flushed and refilled....possible something hanging up in the valve body....dealer is your best bet but also a crapshoot here.....AT shops few and far between.....the TCU might throw a code but probably not if a light does not come on.....

Edited March 9, 201511 yr by pgrahmm

Transam....think it is an A/T....OP have you had the car serviced at anyplace like Bquick....if so check what type of fluid they might have put in....probably does have a TCU...BUT almost sounds like a pump or TQ concern.....is it parked on an angle? Make sure fluid is correct and full...might be a good time to have it drained/flushed and refilled....possible something hanging up in the valve body....dealer is your best bet but also a crapshoot here.....AT shops few and far between.....the TCU might throw a code but probably not if a light does not come on.....

If converter it will mess about in all gears if it is naff. My old autos used one "gear" for first and reverse. I think the idle is the problem here....Of course I could be wrong, but if me I would sort the idle prob. Remember the auto uses it's own oil pump to make the box work, needs engine power....

Perhaps its afraid to go First.

Which could explain the dealer diag....good point.....

It's 8 years old so..... Your 500rpm is to low. It's possible you have a dodgy idle up valve for the air conditioner. Next time your in this situation turn the air off and see if it maintains 800rpm.

The ATF may look OK, but after 8 years it maybe breaking down. A new filter and ATF could be needed.

It's 8 years old so..... Your 500rpm is to low. It's possible you have a dodgy idle up valve for the air conditioner. Next time your in this situation turn the air off and see if it maintains 800rpm.

Do all cars have this valve ??

I have a old VW golf.. Very old.. And engaging the AC kicks the tickover right down. I just assumed an old euro engine didnt have the power or engine management to compensate ??

It's 8 years old so..... Your 500rpm is to low. It's possible you have a dodgy idle up valve for the air conditioner. Next time your in this situation turn the air off and see if it maintains 800rpm.

Do all cars have this valve ??

I have a old VW golf.. Very old.. And engaging the AC kicks the tickover right down. I just assumed an old euro engine didnt have the power or engine management to compensate ??

Yes...they should all have an AIS or kicker/stepper/idle up switch/valve → might be wrong but think moreso on gasoline engines....

This is a 1.8 petrol..

So is this a electronic (ecu) or manual switch ?? Going to be fun trying to explain this one to my non english speaking mechanic..