Transmission Coolers Archives - Transmission Digest
Transtar highlights coolers and warmers for Nissan Versa, Sentra

Transtar highlights its line of coolers and warmers for Nissan vehicles. Models covered are the 2010-2012 Nissan Ventra and the 2013-2018 Nissan Sentra. According to Transtar, the ideal operating temperature for the transmission and fluid is between 160 and 200 degrees Fahrenheit. Transmission fluid cannot be over-cooled, so Transtar suggests adding an aftermarket cooler as

6L80-6L90 Cooler Flow Bypass Valve Kit

This Superior Bypass Kit from Transtar (p/n A104996-5K) allows full-time cooler flow and lubrication to parts. The kit reduces the risk of overheating while under load and increases transmission fluid life. Fits 2010-2021 GM applications with 6L80-6L90 transmissions.

Transmission Coolers, Part 2

Auxiliary coolers have been available for almost as long as automatic transmissions have. For many of us who have been around a while, most auxiliary coolers were used to supplement the factory transmission cooler for towing or other heavy-duty purposes. In the TASC Force Tips article “Contamination and Coolers” in the August issue, we discussed the need to replace some coolers, but I realized that there are no guidelines for choosing the right-size cooler to install.

Coolers and Contaminants

Most of us have been battling cooler and contamination issues for years. We may not realize it, nor care to look for it, but it does manage to rear its ugly head.

First we need to look at the sources. Mike Steen (technical director at Certified Transmission) has spent considerable time on finding these sources. Along the way, I have found a few as well. Hung valves and stuck governors have plagued us for years. We thought the contaminants came from coolers. We bought flushers and flushed coolers, and the problem went away – well, not quite. We still have problems.

AX4S/AX4N – No Go/No Charge

With their fingers crossed and the cooler-return line still in the bucket, they start the car up. The cooler line makes a little pop, a spit, some foamy fluid then, lo and behold, a nice clean steady stream of fluid comes out of the line. Mission accomplished. The converter has charge. After the cooler line is re-connected, the trans is topped off, road tested and everything works perfectly. End of story you say. Not quite yet. The question that remains is what did we do to correct whatever was wrong with the unit? We did not find anything to point a finger at as to the cause of the problem.