Knackered Gearbox???

[retroenduro Member Find all posts View Profile Close retroenduro]

OK so a story is developing here as i type....a while back we were coming home from a camping trip in Vic and descending down the SE freeway into Adelaide. I had the car in 3/4th (the auto 'S' mode) gently coasting down the hill (between 90 ad 100) as i was towing the camper (less than 750kgs). Got to the bottom and the car struggled to pull away. The box would just slip and slip. The gears would change but the slipping was still going on....

Anyway i pulled up, turned it off and on again and it was fine...

So yesterday i took the Prado to Toyota finally to get them to have a look and to also check my injector feedback values - will have a look at those later.

Turns out the gearbox cooked itself (even tho it still works fine) and spat out half a litre of oil. Worryingly i got no warning lights and it threw a load of other codes with traction control and VSC etc again with no warning lights whatsoever...

Has anyone else had this problem at all? Its seems crazy that the Prado couldn't even handle a small trailer yet is touted as being fine for towing 2 ton caravans.....cant be right - surely.

Anyway its still under warranty and they are putting a report together to send to TMC Au. We will see what happens...

[retroenduro Member Find all posts View Profile Close retroenduro]

OK so went in and talked to the service manager and it seems that for some reason the ecu/vsc and brake controller all lost contact...hence why all the fault codes and why i didn't get warned about the 'hot' gearbox. still doesn't explain why the gearbox overheated in the first place....apparently everything is fine though and that slipping box afterward was a 'safe mode'? i assume they just looked at the fluid but i have to go back in two weeks to see if the fault codes come up.

Does anyone have any experience with this?

[Poppy Joe Member Find all posts View Profile Close Poppy Joe]

I would not be happy to leave it at that. I would insist on a complete flush and filter change.
How many Ks has it done and do you have a auxiliary oil cooler fitted.

OK so went in and talked to the service manager and it seems that for some reason the ecu/vsc and brake controller all lost contact...hence why all the fault codes and why i didn't get warned about the 'hot' gearbox. still doesn't explain why the gearbox overheated in the first place....apparently everything is fine though and that slipping box afterward was a 'safe mode'? i assume they just looked at the fluid but i have to go back in two weeks to see if the fault codes come up.

Does anyone have any experience with this?

[fido666 Banned Find all posts View Profile Close fido666]

Ah but Toyota will try and tell you the gearbox never needs flushing and has a lifetime oil that can't be replaced. At least that's what my local dealer's service manager told me and I have heard this from others on here as well.

[retroenduro Member Find all posts View Profile Close retroenduro]

I would not be happy to leave it at that. I would insist on a complete flush and filter change.
How many Ks has it done and do you have a auxiliary oil cooler fitted.

well its still out to toyota who will decide what to do but i kept asking...why did it overheat in the first place when i was only towing a lightweight trailer......

its done 56k and no i dont have a cooler fitted as you would think that from the factory it should be OK towing a small trailer around.....

[Poppy Joe Member Find all posts View Profile Close Poppy Joe]

As Fido 666 states according to Mr Tojo Sealed for life. I have already had that one out with Tojo. Did the flush and filter myself and now have a Second chance.
Seriously if they don't do it Get it done. If it got that hot the oil is Stuffed.
Mine now is so much smoother and has just over 140k on the clock towing a 2.500kg van. It seams ironic the tranny is the same as the bigger brother Cruiser albeit with a bigger Torque convertor towing to 3.500kg.

[retroenduro Member Find all posts View Profile Close retroenduro]

well went in today and it hasn't thrown any codes since...i raised all these point and they want me to come back in another 2 weeks and try to re create the fault...

I asked about flushing and they said they would if it had shown signs of slipping etc (it was but that was down to a 'safe mode' apparently).

I said can you assure me the oil is OK and they said its fine...

I said is it normal for it to overheat towing such a small van they said no... we just kept going around in circles and their answers were not making any sense...they kept trying to blame the fault that stopped the light from coming on as to why it overheated...when i corrected them that it overheated regardless of faults they then didnt know what to say..seems like unless the computer tells them they dont understand.....

Odd thing is the box is fine...changes beautifully - always has done. i wasn't even going to mention it as i thought there was no issue. it was them that said i have 'got it hot' enough to burp about 400mls of oil out of it....

Ill take the CT for another run and see if i can get it to do the same...

[Wildcaddy Lurker Find all posts View Profile Close Wildcaddy]

Mine has the same issue. I would be driving along heading down hill and press the brake, when I do this the brake assist drops the auto down a gear, I then coast down the hill in that gear with slight braking. When I get to the bottom and accelerate it slips even if I manually put it in 5th gear it just seems to have no power and lots of vibration. If I come to a complete stop and then start again the auto goes through all the gears as it should just fine. There is no warning lights that come up and I am not towing anything. I have it at Toyota service today, hope they can find the fault if not maybe ask for a transmission oil and filter change.
Also mine has done 145000kms I was told by the service manager they change the Transmission oil at 160000kms.

[retroenduro Member Find all posts View Profile Close retroenduro]

yep exactly the same...mine only did it once tho...

hmm lets see what your guys say?

[topic97 Senior Member Find all posts View Profile Close topic97]

Do they have a pressure relief valve in the gearboxes?
Otherwise, how are they spitting out fluid without busting a seal?

[Bushbasher Out of control poster! Find all posts View Profile Close Bushbasher]

Auto box can spew fluid out of the breather and also from the rear main seal (output shaft) under pressure.

[Brett1979 Avid PP Poster! Find all posts View Profile Close Brett1979]

I'd consider 160,000km change intervals a very long time between changes for any vehicle. I'd personally do it every 80,000km. Especially if towing a lot. It might have something to do with fixed price servicing and how the dealerships can save money with this offer. If the transmission in your car is also the transmission used in a larger car again, then they'll know they can get away with less oil changes because the transmission shouldn't stuff up during any warranty period so won't be their problem down the track. The oil should in theory not lead to "cooking" of the transmission if not changed for a long, long time. I would lean towards excessive wear of the cog teeth more than anything which will lead towards chomping of the gears when maybe changing into reverse or putting into Drive. Why the fluid is forced out of the housing is anyone's guess, but when transmission fluid is depleted even by only a couple of hundred mills, it will wreak havoc with your transmission and gear changes. With slightly depleted fluid, if you tried reversing up a slight hill your tranny would pop out of gear into neutral and not re-engage until you stop. Pulling up at a set of traffic lights can do the same thing. The car won't find first for maybe 5 seconds or so? Almost sounds like the transmission was overfilled from the beginning or something which didn't leave much volume left for volume increase when heated up through extreme driving conditions and subsequently spewed a whole heap of oil out at that time.

When it comes to late model vehicles no issue (no matter how weird) surprises me anymore to be honest. Doesn't matter on the make or model these days, they all suffer multitudes of mysterious, partly unexplainable, unacceptable issues.