I'm basically set to order a '15 Trail model. I've done a search, google, etc., but can't find a good answer ..

So, does the 5th gen 4Runner w/ auto have a torque converter lock on the highest (at least) speed?

Yes.

Converter lock on 3rd, 4th and 5th.

There is even a flex-lock from 50 to 60 km/h

I thought it only locked in 4th and 5th??

If the 3rd gear is selected in select-shift mode, I do not think it will lock-up. I should have been more clear sorry

But I assure that if you are in ''D'' mode or ''5th gear select shift'', and you gently apply throttle, you will get a lock-up on 3rd gear. You will also get a lock up on a high grade hill, on cruise control if C/C decides to select the 3rd gear.

More than you ever wanted to know

That is the sort of thing this forum needs! Thank you for posting.
Dealer rants and build threads for people who bought new tires...not so much.

Amen brother.

.... and TRDP butt-hurt pissing matches.

Lots of good info here... Thanks!

I sure hope the A/T 4Runners have the trans cooler!

They do. Integrated with the radiator.

Forgive my ignorance. So in the 5th gen 4Runners in order to get a torque converter lock going up steep grades while towing, I should not be in S4, but rather in S5 or D? I just got back from towing my travel trailer up the Santiam Pass in Oregon. This is a brutal climb, as it is about 20-30 miles of nothing but incline getting to the pass, then the pass itself. My ScanGuage II was reading a TFT (Transmission Fluid Temp) of 238F at the hottest point. I was in S4, but had to drop down to S3, just to maintain ~40-45 MPH. During this climb, the tranny temp was rising fast, and after reading this thread it sounds like maybe my torque converter was not locked. While on the straight stretches or low grades, I was averaging 175F-180F.

Is it best to stay in S5 and give it more gas to lock up the converter in gear 3 or 4 when climbing? I thought being out of OD was best. Thanks for the help.

As good as that document is... it is still vague about lockup operations. My guess would be it can happen in any gear.

It seems to indicate that a full lockup will happen at "high" speed with no definition of what that speed is. There is no mention of full lockup as it relates to gears. It does indicate throttle position is a major factor, so high speed + any throttle position = full lockup. low speed + low throttle position = full lockup.

Bottom line, you are only going to get full lockup while towing if you somehow maintain a good speed (nearly impossible with a t4r on steep grades)

The flex lockup is pretty well defined. It says it only works for decel in s4.

In D, or s5 it will work for accel in 3-5, and 4,5 for decel. The flex lockup seems to be an in between state (not what you really want to cool the trans).

Sure would be nice if they gave actual speeds and TP.

Attached Images

 

I could have given it more gas while climbing those grades, but was afraid to get the transmission even hotter than it was already getting, but it sounds like I should shift from S4 on level grades to S5 and give it more gas to try and increase speed to get it to lock. Will this keep transmission temps lower than trying to "baby" it up the grade at S3 maintaining 40mph?

I attached a photo of the conditions of the 4Runner at the top of the Santiam Pass yesterday.



Thanks.

I hate to sound negative, but I really don't think there is much you can do on a really steep grade. More gas in D or S5 will only put it in "flex" lockup (which seems like it would not help much). Momentum and speed appear to be key, but hard to do on a sustained climb with such little power on tap.

I have never towed anything substantial with a 4runner, but I can imagine it being a struggle. People seem to claim they tow in the mountains with "no problems". Does not add up for me.

Have you tried adding an additional trans cooler. A janky approach I've seen used before is a sprayer (think washer bottle...) to mist the fins where the trans lines run. This can provide a cooling boost for sustained climbs.

How much does your trailer weigh?

Next time you're in that situation, give 2nd gear a shot. I'm curious to see what would happen to the trans temp. My guess is at low RPM and high gear, less fluid runs through the trans cooler. So, it stands to reason that temps would drop due to increased cooling (due to more fluid circulating) if you shifted to a lower gear. Maybe someone here can confirm whether trans fluid circulation is linked to the OUTPUT shaft speed, or INPUT shaft speed. @1engineer

Max torque output on these motors is around 3,250 RPMs as well, so make that your target when towing and I think you'll have much more success.