The Nissan Path

Has anyone added an additional transmission oil cooler to their rig? I've been looking at the Mishimoto heavy duty transmission cooler with an auxiliary fan. I've noticed since putting 33" tires my transmission tends to run hotter especially if I'm towing my 6x12 trailer also looking at possibly getting the griffin radiator with the shroud and auxiliary fans for the same reason with my engine temps.

What temperatures are you seeing?

last time I towed was a 420 mile trip from oklahoma to texas with some hills and very strong head on/ cross wind. At one point my engine gor up to 220 F and my trans got up to 210 F.

If that's what you get in a worse case scenario, you'll be fine. "Normal" ATF temps are usually in the range of 175-200 degrees F. It would have to get to 240 degrees before varnishes would start to occur. Engine overheating wouldn't occur until coolant temperatures get close to 250 degrees in the pressurized system.
If you are still concerned, a more efficient radiator would probably be all you need. As you bring those coolant temps down, the ATF temps should drop as well. Stillen sells the CSF all-aluminum radiator which would likely do the trick at less cost and complication. However, if money isn't figured into the equation, there's nothing bad to say about Griffin.

oh ok I didn't know at what temperatures my motor and trans were in danger. In that case I will just upgrade to a CSF radiator to help with the temperatures.

Keep in mind that while the boiling point of water is 212 degrees F., that boiling point increases 3 degrees for every pound of pressure. The reservoir cap, which is the vented cap in the system, is rated at 16 PSI. That will raise the boiling point another 48 degrees to a boiling point of 260 degrees F.

I've been looking at doing the same. Did you go with a secondary Mashimotos transmission cooler? Also, the CSF radiators seem to be the best option, but some places have said they have had problems with cracking. Did you end up going with the CSF?

do keep an eye out on those csf radiators my buddy just had his crack also probably after 20k miles.

I dont have the link on hand but smj can ring in on using a 350z thermostat to open at a cooler temp

As far as the transmission cooler I run 35s and only have overheated the transmission plowing through 2' snow but on like 10mph not getting enough airflow through the front so maybe an aux high speed fan on long trips

How are you guys measuring the trans temp while driving?