Ram 3500 HO Aisin Temps

[Dave B]

Hello,

I new here and I would appreciate any insight on something I noticed today. Normally my 6.7 HO with the Aisin temps usually run about 163 to 167 when I drive the truck. I’ve seen temps has high as 177 when I was pulling long grades with the camper this summer doing about 70mph.

Today I drove the truck and in traffic completely empty I notice my temps running high (which has not been normal at all). The trans temp went to 186 degrees while idling at a light (that was the highest). That’s not normal for my truck so I’m wondering what might have changed. The only think I remember was one hard shift when I hit the pedal going through a yellow light early today. Not sure if this has happened to anyone where the truck operating temps would completely change. Any insight would be very much appreciated.

 

[MEGA HO]

Lugging transmission in constant stop and go traffic will make it run hot.
It will run much cooler even if you tow at highways speeds when the TC is locked up

 

[Dave B]

I agree but it’s never done that before today. At least I’ve never seen that and I have the 4 main temps on my main dash screen so I keep an eye on it closely. The weird thing was it was 76 degrees and when I finally took it on the highway for about 10 miles it only cooled down to 174. It didn’t break back down into the 167 area like I expected. I also went to my son’s house and let it cool down for about 45 mins. It ran at 165 degrees at about 70 degrees outside with no traffic. Coming into the neighborhood I was rolling in 3 gear about 30mph and the temps climbed to 170 before I hit the house. Like I saying, I don’t ever remember it passing 167 on daily driving around town before today.

Thank you for the response.

 

[MEGA HO]

well then I don't know, if not air temperature, was humidity much different from before? check your transmission fluid level and cooler fins, see if they're plugged?

 

[jetrinka]

Stop and go traffic? Moving?

 

[Dave B]

the weather was a little humid today but not bad. I’ll check the levels tomorrow to see if anything is low. Appreciate it.

 

[Arth]

I've had my aisin temps as high as 196. Was a lot of stop and go traffic. I think it's all normal.

If there was a need for cooling you'd hear that fan kick on for sure.

 

[MEGA HO]

I've had my aisin temps as high as 196. Was a lot of stop and go traffic. I think it's all normal.

If there was a need for cooling you'd hear that fan kick on for sure.

I may be wrong but I think the transmission cooler is passive cooling. Only rad has a fan behind it.

 

[Dave B]

I may be wrong but I think the transmission cooler is passive cooling. Only rad has a fan behind it.

I think that was my concern. I didn’t hear the fan kick on and the temps kept climbing. I’ve never seen over 181 on the truck at all and that was pulling my Toy Hauler climbing out of Laramie WY. The truck is a 2021 with about 16k miles on it and it’s been absolutely perfect so far. I’ll check the levels of the fluid tomorrow and make sure nothing is low. I appreciate the insight.

 

[MEGA HO]

If it never happened before then there might something be off, but in cities stop and go traffic and passive tranny cooler there's not enough airflow going through and slipping TC generates a lot of heat in stop and go, vs when it's locked at highway speeds.
If you have a pressure washer give it a spray, it may not look dirty but still be dirty. Won't hurt it

 

[Brutal_HO]

If you do a lot of stop and go driving where's it's consistently hot, you might want to install a bypass kit. You might not like it in the winter if it gets cold there.

I'm holding out/hoping that Mishimoto updates their (adjustable) bypass kit for the current AS69RC. With theirs you can easily add/remove the thermostat for different conditions.

 

[bigbendrecycle]

2022 Ram Laramie SRW 3500 HO This summer I had the trans temp reach 217 and the big fan kicked on. I was towing 19k up a steep gravel grade. After that, I have seen in the 170s. After the 217 day, I called the dealer. They said the Aisin is meant to be worked and short periods of heat are fine. Make sure to follow the manual for fluid changes in the chassis.