I never see transmission issues appear when I check for new threads in this forum. Are we just lucky? The Land Rover forums are FULL of transmission issues (and air suspension faults, check engine lights, and no start conditions).

The A750, it appears, save for an additional gear, has the same design, same strength internals as the A760.

You know -

The same A760 that sits in a Tundra while it tows 10k pounds.

The same A760 that stays under power train warranty even if you got the TRD supercharger (provided the dealer installed it).

Is this simply due to over engineering, or some magic going on in the Tahara plant?

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I can speak to Land Rovers, who paired a dinky ZF transmission previously only used in sedans, to a 5500 lb SUV, and was rated for less torque than the engine produced. Lockup in EVERY gear, and design operating temps between 180-190F. Certain shortened life.

Does anyone have any data points for what our 4Runners’ transmissions temp reaches during operation?

There are a few threads on trans temp. Check out Scan Gauge II or OBD Link MX or other OBD data displays. From others posts I’ve seen temps typically range from ~110 - 210*F. The higher side occurring under continuous heavy loads and higher ambient temp. ~160-180 ideal operating temp for efficiency and protection and fluid life. You really don’t want to go much above 210, things start to go bad as you approach 240 or so. All #s SWAG, add +/- 10*

You sound new to Toyotas. It is a very different world from the Eurotrash.

There are plenty of threads on these transmissions here and in the Facebook groups. They aren't infallible

Glad to be here. Actually get to read about upgrades not just break/fix


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hard to have issues when its only putting out 230 hp to the wheels

This is pretty much what I’ve seen when monitoring temps. I don’t see 200 or above unless I’m towing in hilly terrain. I don’t recall ever seeing more than 215. I do not use 5th gear when towing.

"The Car Care Nut" has a youtube video discussion on the A750, he is a Toyota tech and he states it is a well built and over-designed transmission so it should last a long time with proper maintenance, which it does.

i saw the "car care nut" videos as well. made me feel a lot better about our 4runners. The engine also, both simple and over engineered. I will take that over all the fancy 10 speed transmissions and turbo's with better MPGs.

I've read that the 6th gear is actually present, but the trans control module is only programmed to use 5 in the 4Runner.

I wish I could find the source where I read that instead of looking like I just pulled it from my butt lol

It’s definitely plausible.

That actually happened with the Mopar 45RFE/545RFE/65RFE.

TCM tuned out the additional speeds. The “tell” is that your 3rd gear is 1.00, not 4th.


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FWIW:

The A750 does share the same gear train as the A750. So it does have the 6th gear internally. The problem is that it is built missing one internal part (not a gear, but a clutch ring component), and most importantly the A750 has a different valve body. So unfortunately it isn't just software. It doesn't have enough valves in the valve body to shift into all 6 gears. I don't know if it would shift through all 6 gears if you just swapped valve bodies. The housing is exactly the same, so they would pretty easily bolt in place of each other. I don't know why they stick with 5 gears in the 4R when they put the 6 speed version in other foreign models. I think they really just DGAF about the USA market. I can't really think of any other reason not to use the 6 speed.

The Tundra 5.7 is the AB60 rather than the A760. It's a bigger heavier transmission. The A750 was used behind a warrantied supercharged 4.7 v8 in the past gen 4Runner. And the A760 is IIRC what was installed behind the 4.6L tundra. I think the new 10 speed will probably be used in the full range of toyota BOF going forward though. I'd guess it'll be cut down to a single transmission. But the 10AT is fantastic, so I'd be really happy to see it come in the next gen 4Runner and Taco.

The AB60 in the tundra vs A750 planetary gear set below is a good visual of the comparison. Both are nearly identical in design. The AB60 is just scaled up a size category. Both are very reliable. Probably the most reliable production automatic light duty truck transmissions ever built. I can't think of any that would be better.




Interestingly - I've read that the 9 solenoid valve body on the AB60 and A760 suggest that it would only take minor tweaks to make them shift through a potential of at least 8 gears. Typically a 3 planetary gear transmission would have at least 8 possible combinations as long as you can choose every clutch pack combination. So it's at least plausible that even the A760 and AB60 have the potential for more gears somehow. I just don't know enough about them to really break down if that's possible or not without spending a time looking through the schematics.

In my opinion, the A750 is a pretty good transmission. Just gauging by the posts on here, very few issues ever but they do happen time to time. Owning a 4th gen and a 5th gen, I'm satisfied with the transmission but I do prefer the transmission tuning in the 4th gen better. I also own a 2017 Tundra with the AB60/5.7 combo and love it. It's towed a bunch of different things and never has an issue. The common thing with these transmissions is that they feel more commercial/industrial to me than some of the slush boxes in other vehicles, and I'm ok with that.

Regarding the possible 6th gear in the A750, that would be a nice bonus for those that have re-geared really low. For those of us that haven't, I'm not sure it would be worth it since both 4runners barely stay in 5th gear as it is. Maybe that was Toyota's reasoning. The Allison 1000 found in GM HD trucks with the Duramax diesel and the 8.1 gas big block was similar. There was a 6th gear present in the earlier versions but wasn't "available" until the 2005 or 2006 model year. The major differences were the valve body and trans programming.

that's fascinating about the unused 6th gear.

with American's constant request for more speed (usually in the form of more displacement) i wonder if they decided to keep the 6th ratio locked away because the 5th gen would bog/hunt even more than it already does and get an even worse reputation for adequate power. that's the only other theory i can think of besides yours.

I kinda feel like its just because they'd need to use a different gear ratio than 3.73 in the diffs and that is just a popular, strong and easy to come by gear.

A 2nd OD and 4.56 gears stock sounds pretty nice tho.