2014 Prado 150 3.0TD 6-speed Auto Change out from 5 speed Auto

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Is there a way of changing out the standard 5 speed auto, to a 6 speed auto?

Do a fair bit of towing of caravan and concerned that running the engine at >2500 rpm, will ultimately reduce the life of the engine given the increased work load, and hence looking at changing out to potentially a 6 speed auto

[404pug Avid PP Poster! Find all posts View Profile Close 404pug]

I don't know if it is possible BUT if you are towing you should be in 4th gear on both gearboxes and not drive so there is no advantage in swapping. I assume a 6 speed box will not be cheap.

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

It will not be possible to swap a 5-speed auto to the later 6-speed. Post 2015 Prados have the AC60F 6-speed auto transmission matched to the 1GD 2.8L engine. When I say 'matched', I mean in every sense of the word: the gearbox is electronically controlled by the same ECM as the engine. The older 1KD 3.0L engine and gearbox have separate ECMs.

[gunda Member Find all posts View Profile Close gunda]

I don't know if it is possible BUT if you are towing you should be in 4th gear on both gearboxes and not drive so there is no advantage in swapping.

I have read this statement here a number of times, but I question is as a blanket statement, at least for the current model. I agree not do drive in D when towing, but on flat terrain my MY21 Kakadu locks in 5th quite readily, and the ATF temp is quite stable. It's possible to lock in 6th in the right situation, and again stable ATF temp. What you do have to do if you use either 5th of 6th is be alert to upcoming slopes, and shift down to 4th before it's needed, and sometimes even 3rd, and then shift back up only well after it's not. Don't let the transmission struggle before shifting down, do it before it struggles.

I'm aware that older models had locking issues, but I don't find that the current model does, so I don't agree with the blanket statement.

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

If the torque converter remains locked then the gearbox will generate very little heat. If anything, the ATF temperature will be maintained to the temperature of the engine coolant, since the heat-transfer element in the (main) radiator works both ways.

I find that it is difficult to maintain the focus of changing the geabox in-and-out of 'S' mode when approaching incline/decline with everything else that happens inside a car on a long trip. I have found that, when towing on a long trip, there is minimal impact on fuel economy by holding the 'box in 4th gear and (almost) guaranteeing that the torque converter remains locked. (The torque converter will still let go when towing and faced with a steep incline.)

[gunda Member Find all posts View Profile Close gunda]

I've tried towing in 4th, but I find that it's not comfortable to drive at highway speeds with revs that high. YMMV. Keeping an eye out for upcoming gear changes keeps me focused on the road ahead.

[carco Advanced Member Find all posts View Profile Close carco]

I know where Nathan is coming from, such an old fashioned huge jump from 4th to 5th in those gearboxes. 5th in a 6-speed feels just right.
But your KD will happily tow in 4th with moderately high rpm.
When towing I’m out of 5th as soon as I feel the engine working more than usual. Let her rev.
As for 5th and 6th being “weaker” gears than 4th, that’s simply not true. Might be so in a manual box but an auto drives all ratios via clutch packs, doesn’t care what gear you’re in, the power is going through a clutch pack.

[kizbot Member Find all posts View Profile Close kizbot]

While 2500rpm feels bad at freeway speeds, it's not terrible for the engine. The engine is actually under less load at higher revs. This will result in better EGR temperatures. The engine is actually running cooler with increased breathing. It's also better for the transmission vs unlocking in 5th and driving up temperatures.