@cc93cruiser...your are cruising toward a very big bill if you don't intervene immediately on this. Yes, the auto trannies always ran hot. There are several things that contribute to it that are flat out a design deficiency of the vehicle. Don't take the advice to ignore it, "It's a Land Cruiser." I can tell you after living with mine for 30 years as an original owner, that will take a big bite of our your ass and wallet. The tranny heat is a killer.
I presumed as you. I was too busy to intervene ten years ago, and had to have the tranny rebuilt. It drove as a daily driver for two more years, then was largely retired. This past year I jumped into restoration. I had originally planned a 5-speed mod, but started studying the auto closer. I learned the factors that contribute to the tranny running so hot. I went to work to overcome it.
Many members here have given you good advice, but not what will be the most effective in bringing your tranny operating temp down...and I mean WAY down. I took all those same suggestions, and some that no body else has done to my knowledge here.
@BlackCat has come the closest.
I began drive testing like you with a digital thermometer, and I was in the same boat; tranny with a load reaching 300 or so. Upon completion of my mods/improvements, I'm now running 145-165!!!
The factor that nobody seems to notice, but I discovered and addressed was the effect that intense radiant heat from the nearby exhaust is contributing to tranny operating temp. It's a huge factor. It's easy to identify with your digital thermometer by shooting both driver side of the tranny and the passenger side. What to do? Below is what I did.
I did this as a building block approach. First I figured out how to install a 12" condenser fan. Then I replaced my aging radiator with a new one with an integral transcooler. At the same time I added a 70268 transcooler directly in front of the condenser fan, plumbing it in series with the new radiator. I tested at this point, and the cooling was dramatic, but "imbalanced." The driver side was still considerably hotter. The solution to that was this
Amazon product ASIN B00CF2RGHQ. This heat shield attaches directly to the exhaust where it is closest to the tranny. It is designed to stand off from the exhaust about 1/4" or so. So the fabric shields, and their is air passing between it and the exhaust.
Tested again, and this was the final improvement. This all basically cut the operating temp of the tranny in half.
You can see photos and descriptions here on my restoration thread beginning here
Builds - Sentimental Restoration of Family 1990 FJ62 and continuing here
Builds - Sentimental Restoration of Family 1990 FJ62 and posts 106 and 135.
Not to toot my horn because, as we know, even a blind squirrel finds an acorn every once in a while. I found several and basically overcame the design deficiencies that make the tranny run so hot and destroy itself.
Good luck.
.... My goal is to be able to daily drive it if need be or to be able to take it on long trips with the family... One day it will be converted into a manual transmission with the H55F, but for now I will enjoy the slushbox.. For know I am wrapping up the Front axle service with new bearings and now spindles too... The oem had a lot of pitting were the bearing races ride on...
