Engine/Transmission (1998.5 - 2002) Transmission vs. differential temps

[John Berger]

Ever since I read Joe Donnelly's NV4500 gear lube article where he recommends monitoring transmission temps if running with a lube other than Castrol, I've been curious to tow heavy and be able to do just that. I'm running the Amsoil Series 2000 75W-90 in my transmission. Shifting has been harder and not as smooth "all" of the time since I've been using this lube.



My transmission temps ran close to 200 degrees, which was the same as the differential. The transmission lags behind the differential relative to how fast it gets warm, but the two seemed to "equalize" right around 175 degrees. The opposite is true for cooldown, with the transmission taking longer to cool than the differential. I associate this with the transmission being mated to the engine. I'm running between five and five and a half quarts of the lube in the transmission. I have the Eaton Fuller filter setup that Geno's sells and one of Vernon's fastcoolers installed. By the way, the truck shifts much more smoothly when I tow the 5'er. I will have a much longer haul next week to really get a feel for the temps, but it looks like both ends of the drivetrain pretty much run the same temperature, which from the article Joe wrote, left me with the impression is a good thing.

 

[TomGolden]

Well, I don't tow anything, or ever haul much, but here are my experiences.



Been running Amsoil Series 3000 5W-30 100% synthetic oil in my 6 speed transmission for the last 15K miles. Have had Amsoil Series 2000 75W-90 synthetic gear lube plus MagView rear diff cover on for the last 20K miles. Have had two Fastcoolers on transmission for the last 8K miles. Installed SPA gauges in both transmission and rear diff 3 months/3K miles ago. It has been averaging around 95* here in Sacramento ever since I had the gauges installed.



My transmission and rear diff temps are almost always within 5* of each other. So far, I have never seen either go beyond 155*F... ...



Tom

 

[Steve Campbell]

John Berger....

Thanks for the info. I am running the same set up (filter on right, fast cooler on left side) on my transmission as you and have no guage. I should not assume, but I will anyway that my temps are in your range. So, until I spend the bucks, I will just drive the truck!!!