Terrible Auto transmission.

[Whitey Shockie Maker of the Month Award Find all posts View Profile Close Whitey]

Hey The d,

Do you know if the previous owner did a lot of towing, has the Prado been used hard off road before you purchased it?

You've flushed and have added a cooler, but it might be worth dropping the pan and checking the pickup screen. Burnt oil can clog up the screen with sticky organic colloids.

I'd also try Penrite ATF LV synthetic just to try a different fluid in there.

Hope you get it sorted!

Best

Mark

[stanmiko Member Find all posts View Profile Close stanmiko]

Honestly, I have found the A750F to be one of the best 5-speed autos in any vehicle I have driven. In and around town you shouldn't be driving in D anyways... I always leave it in 4th unless I am hitting at least 80km/h zones.
When you did the fluid change, did you change out the filter as well?
I would be seeking the advice of an Auto Tranny specialist...
And, yes, it is meant to shift down a gear if you touch the brake heading downhill...

[The d Junior Member Find all posts View Profile Close The d]

Hi. Yes I changed the filter and auto oil at the same time as fitting the cooler.
I fittted the towbar when I bought the car, so it never did any towing until I bought it, and I have only towed a handful of times my 1100kg camper
I haven't taken it off road since owning it and doesn't appear to have been off road much in its life.

There wasn't too much crap on the pan magnets than you would expect for 129,000km. I honestly think it feel like a hydraulic pressure issue or an electronic issue, like bad software, I had it updated a couple of months ago.

Oh well. It must be a one off bad trans. Maybe there is a component on the way out.

[Whitey Shockie Maker of the Month Award Find all posts View Profile Close Whitey]

Hey,

One last possibility, you might consider upgrading the valve body;

http://www.pradopoint.com/showthread...ale-Automatics

Expensive I know, but better than shelling out for a replacement box.

I think you've just been unlucky and have a problematic box.

Good luck!

Best

Mark

[ozimacca Member Find all posts View Profile Close ozimacca]

How about getting another Prado owner to drive it, you live in Perth so you should be able to find someone to test it.

Maybe someone on here or FB will swap a drive with you for comparison

[kerp123 Lurker Find all posts View Profile Close kerp123]

Hi i got similar issue with my 2016 Prado. While im driving on hill running speed of 80km/h and stepping on a brake to slow down, the engine will rev up and hit it to almost 3000 rpm. Its only doing it when I go down hill. I've ask toyota on my last service and they say it's normal. Seems like it's not believable. Should I go back and have it check again?

[nudgebar Member Find all posts View Profile Close nudgebar]

its normal , and a characteristic of the Aisin V4A / V5A autos fitted to many jap cars since 1997 or so. but to be more specific - not the gearbox itself as such , but the programming of the ECM which controls the gearbox.
on a previous vehicle i had to find the brake light switch wire going to the transmission ECM , and snip it . problem solved

[krypto Avid PP Poster! Find all posts View Profile Close krypto]

Hi i got similar issue with my 2016 Prado. While im driving on hill running speed of 80km/h and stepping on a brake to slow down, the engine will rev up and hit it to almost 3000 rpm. Its only doing it when I go down hill. I've ask toyota on my last service and they say it's normal. Seems like it's not believable. Should I go back and have it check again?

This is actually a safety feature as it uses engine braking to take some load off the brakes, something people could control themselves when driving a manual.

[wanted Member Find all posts View Profile Close wanted]

Some times it is just a tap on the brake pedal other time it takes a little more firm pressure and a few tries.

I want this 'feature' to be more predictable as to when it will come on. It does not happen every time I want it to come on but when it does it is great. I find it very useful and apart from slowing down when you need to pick speed again the vehicle is already in a lower gear and you do not have to wait for the turbo to kick in, gear to change etc.