scan gauge

At the risk of thread hijacking, what temps do you see when towing and not towing, and what temp do you regard as too high? Asking as someone who just installed a Scangauge II specifically for monitoring the ATF temperature when towing (2t - 2.2t) and is trying to understand what it's telling me.

My BT50 is a PX1 with a Mazda skin. Mechanically a PX1. I fitted an air to oil transmission cooler to it with a high power thermo fan, bypassing the OEM water to oil cooler which was inadequate when towing in hot conditions. (The mod is a fanless Wholesale Automatics kit, to which I added the fan.)

Before the change it used to run the ATF mostly at 97 deg C, but under moderate load (eg towing our 2200kg hybrid camper uphill on hot days) would heat up alarmingly to 130 and on occasion start to reduce power to limit the heat build-up.

Now it runs at 84 and rarely gets above 100.

Keeping it brief, I have a LC200 & when towing, the trans temps can rise dramatically. I have seen up to 120 deg when in hilly terrain. On the flat, temps will be around 75ish when towing, but i can get it lower with gear selection, speed, TC lockup etc. Not towing on the flat at the speed limit, the temps will be around 60 deg, give or take. It also depends on what gear is selected & whether the torque converter is locked. My trans is a 6 speed & I always tow in 4th. I also have a TC lockup kit installed. It is for these reasons that I say get a quality ECU reader that reads ATF temps so you can determine what gear/speed etc is best to keep temps down.

Thanks. I am towing the same van as Frank with a current spec (six speed auto) Prado. Transmission temps are in the 80s when not towing, and hover around 100 when I am. Typically around 98, but can be several degrees higher, with the occasional brief upwards spike, but nothing sustained of the sort that you chaps mentioned. I tried towing in 4th and I didn't think it made an appreciable difference, but will give it another go. I have read that in the 80s is normal and in the 120s bad, but not sure about say 98-103.

I'm also monitoring transfer case temps and they're generally higher than ATF, and they're more inclined to spike and slower to come down. I'm not sure what this means. The current spec Prado gearbox is supposed to be better isn't it, as in less inclined to slip and switch? A tranny cooler isn't going to fix that, and I don't get the impression so far that towing in 4th does either.

Towing 1.6t with a auto Pajero (Aisin transmission) in 4th and AWD mode as recommended by the manual, the transmission locks and the temp stays on 72 degC on the flat. The hottest I have recorded was towing up the Oxley Highway when it got to 112 and no amount of downshifting could lock up the transmission. If I was doing a lot such roads I'd fit a transmission lock up kit.

TEMPS for PX Rangers with 6 speed auto Boxes.
Min = 65c
Normal = 79 to 93c
Max = 135C
Damage = Occurs after 148c
This was from a sheet of information given to me when I had an external Auto cooler fitted to my PX1.
With My Max load when towing of 5900kg (van & Vehicle) my tranny runs at 90c on a hot day and has climbed to 110c in the high country mid summer. However the normal load with van on is usually around 5500kg so heat is also down in the tranny.
I also believe that these readings are from the sensor as the oil leaves the box heading for the cooler.
Also it takes some time before the tranny reaches 65c on a cold morning.