If you do not have a transmission cooler on your truck and you plan to tow or haul heavy loads or you are in heavy stop and go traffic and use 4X4 low a lot , consider purchasing a cooler . The cooler thats built into your rad is designed to cool the transmission with the weight of just the truck by itself .When you are in 4x4 low , your torque converter is usually in the stall stage and creates a tonne of additional heat .
160 - 200 are considered normal temps providing your engine radiator is functioning properly . If your engine overheats , your transmission will also overheat
Normal fluid temperature in transmission to be 175 deg. F.
Rate of oxidation to double for each temperature increase of 20 deg F above normal (175 deg F). As oxidation rate doubles, useful life of fluid is cut in half.
At 175 deg F life is 100,000 miles
At 195 deg F (20 deg above 175) life is 50k miles
At 215 life is 25k miles
At 235 life is 12k
At 255 life is 6,250
At 275 life is 3,000
At 295 life is 1500
At 315 life is 750
At temperatures much above 300 deg F the metals in the transmission will tend to warp, twist etc. high temperatures causes the formation of varnish deposits which impair or pre vent transmission operation.
At a fluid temperature of 415 deg F fluid life is 30 minutes!
Source: Empire Lubricants Inc.
Consider a scan guage http://www.amazon.com/ScanGauge-Comp.../dp/B000AAMY86
Here is the best information for the scan guage http://www.tacomaworld.com/forum/2nd...-pressure.html
This is how Low Pressure Drop technology works::
When Automatic Transmission Fluid (ATF) is cold it is viscous. The unique Tru-Cool design allows the colder, thicker ATF to flow more efficiently through two open bypass channels positioned at the top of the cooler. As operating temperatures increase, the ATF becomes hotter and thinner, It's then directed through the core where it is cooled. Tru-Cool's highly efficient cooling technology combines improved protection against lube failure with optimal heat transfer.
Long Tru-Cool Oil Coolers offer advanced cooling protection for many towing applications. The advanced technology out performs TUBE & FIN Designs, Delivers up to 15 times less flow restrictions, 30% more cooling delivers maximum heat transfer, Self-Regulating for maximum lube flow protection through start-up, varied temperatures and driving conditions, heavy loads and towing.