One of the worst enemies of your trucks automatic transmissions is heat. The additional heat created from towing compounds this problem and can cause an early demise of your trucks automatic transmission. This is one of the reasons that many heavy service trucks are preferred with manual transmissions.
One of the easiest ways to combat this heat buildup is to replace the factory transmission pan with a higher capacity aftermarket aluminum transmission pan. The higher capacity, some time up to an additional gallon allows the hot fluid to spend more time in the pan. The more time the fluid spends in the pan the more heat it will lose through the pans ability to radiate heat into the air. The more fins the pan has the faster the pan will disburse the heat into the air similar to a radiator.
Many of the aftermarket pans have options like magnetic drain plugs to remove material from the transmission fluid and additional bungs for transmission temperature gauges.
Many vehicles that come from the factory with a tow package will come equipped with a small external transmission oil cooler mounted up near the radiator. These factory transmission coolers most of the time are barley adequate for towing a bass boat up a grade much less a big enclosed trailer filled with toys.
There are many types of aftermarket coolers on the market; many of these coolers have BTU ratings and or weight recommendations which can be confusing at times. Always combine your vehicles curb weight as well as your trailers weight to see if your cooler is close to matching your coolers capacity. I always recommend the largest cooler you can fit in to a given space. You cannot go too large a cooler.
When it comes time to change your transmission fluid don’t let price guide your decisions. Saving $50 on cheep trans fluid can and probably will turn in to a $1,500 trans rebuild down the road and usually in the middle of nowhere so you can usually add a hefty tow bill on top of that as well.
It is always to go with O.E.M or a quality aftermarket manufacture with a good track record. Many vehicles O.E.M. fluid is synthetic which I highly recommend but first check with your builder or the manufacture to see if your transmission is compatible with synthetic fluids, many are not so be careful.
Many company’s offer both high grade mineral based and synthetic fluids like Lucas Oil which I have had great success with.
For You 4X4 Guys
For all you guys out there with 4 wheel drive vehicles don’t forget your transfer case. Weather you use the 4 wheel drive or not the transfer cases is still turning as you are going down the road. The modern transfer cases have a pump in it that pumps fluid to the top of it to keep the bearings cool and lubricated. The early transfer cases have no pumps and rely on splash oiling.
Most transfer cases have no source for cooling other than what can be radiated out through the case and what they can radiate into the transmission case. Because of this lack of cooling I always recommend a synthetic oil in the transfer case as synthetic oil will not break down with excessive heat.