Something I’ve had to do for a while, been a little lazy, was to get a transmission cooler into the Dmax for towing. Having had our camper for close to a year now, the transmission temperature got to over 120c in the Vic High Country and on the beach. Towing in 45c ambient at Christmas through Cameron Corner and West NSW, it was often sitting around 105c.
So, which one to choose. There are options, but I went with PWR for a couple of reasons.
The Dmax has a transmission heat transfer system between it and the engine cooling system, which works fine driving the car, but not when towing, even my lowly 1.6T camper. Towing half its rated capacity sends the transmission into some awkwardly high temps under normal Australian conditions, let alone I would hate to see what happens if towing the rated 3.5T. It only gets worse in offroad and loaded conditions, such as beach and long steep climbs.
PWR are the leaders in this stuff. If memory serves me correctly, Wholesale Automatic transmission coolers are made by PWR. So why didn’t I go with them? Well, PWR sell a low pressure cooler, which means, the transmission system is not designed to pump oil a distance through various cooling systems. The system is designed to pump oil into the heat transfer and back to the transmission. Wholesale run a dual cooler, which increases the pressure and work the pump has to do.
The PWR system is low pressure AND it still uses the existing heat transfer system, which is important for warranty. The oil comes through the heat transfer, into the cooler, back to the transmission. The idea of the trans cooler is to stop the spikes. If you bought a system that bypasses the heat transfer system, then you voided your warranty, let alone you stopped most of the transmission cooling because you’re now relying upon the fan activating to draw air through the cooler, which the fan is not designed to focus upon, so your transmission may run hotter when not moving.
IMO, having the stock heat transfer system stay as part of the process, is important. IMO, if you wanted to bypass the stock system, you should add a thermo-fan to the transmission cooler to operate independently. That would solve that issue.
My limited understanding, is that every degree counts for the life of the transmission. You can’t run it cool, but you also can’t run it regularly over-heating. Based on a small run I just did, the results speak for themselves by lowering the irregular spikes in the transmission temp. The transmission temp at speed ran a few degrees lower than the engine cooling system, but it didn’t spike when I loaded the vehicle to do extra work. That is what I wanted, a more stable cooling of the transmission, instead of hitting 120c when working hard for short periods.
Yet to test it in 45c ambient again, but I will in time. If I find it spikes then, I will be adding a thermo-fan myself.
Update. Towed the camper, 1.6T, in 40 degree Celsius ambient, with the way PWR engineered this to work, I didn’t get above 90C in the Vic High Country. That is a huge difference between the 110C – 120C that was normal for me towing in the VHC without the trans cooler. As such, it kept the engine temps lower as well, as the heat transfer system isn’t working alone to try and regulate the transmission temps.
Really impressed with the PWR setup and it still using the heat transfer system, not just bypassing it like many tell you.