Engine/Transmission (1998.5 - 2002) NV4500: How hot is too hot?

[DEZLPWR]

After taking a 45mi trip on the freeway this evening, when I pulled into my driveway, I decided to crawl under the truck and check things out. I put my hand on the transmission and I could only hold my hand on it for a couple of seconds. I was surprised at this because I have the Fastcoolers installed. I hate to see what the temps would have been without them!

My avg speed on this short trip was 70mph and I was running empty.....

Does this seem normal? I have never crawled under the truck and put my hand on the transmission right after a good run before, so I was just curious. I know some heat would be normal, but it seemed hot.

FWIW, I have almost new Castrol Syntorq oil in the transmission, and the oil level is full.

 

[STPH]

I just today put a temp gauge on my NV4500 and registered 170 deg on a 100 mile trip empty. I think that this is normal but I too need input. steve

 

[M Barnett]

I have had a gauge on mine for years. Here in the desert, the air temp is over 100 everyday and mine will run 150--180 with no load. In the winter it may get up to 140 in 60 degree weather if the drive is long enough.

Michael

 

[John Berger]

I've got a gauge ordered for mine and I also have a fastcooler installed. My differential temps will run around 200 degrees unloaded, on a long trip when it is hot. When I tow, it is not unusual for me to see temps in the 220-230 range. I'll post what I see once I get the transmission gauge installed.

 

[Bob Beauchaine]

I've got a Fast Cooler on the drivers side and a filter on the pass side. Sunday I ran about 5 hours in 100 degree weather and my transmission never went over 180 and rear diff peaked at 165. I was not towing but my truck weighs in at 6950 lbs. with all the "stuff" in the bed.

Happy trails

Bob

 

[MikeR]

You bet it's going to be hot! See, the heat generated by the engine is also being transferred to the transmission because they're bolted together.

The fastcollers add more fluid to the trans case, but I woudn't bank on a big temp drop.



-Mike