Tranny temps

[powerboatr]

this past week, we took a trip up to Little rock
we were loaded up and heavy, right near 40k gross combined, granddaughter brought lots of toys and CLOTHES
air temps were hovering at 99-102 and the asphalt was like soft serve ice cream
i was running 63-64, sort of staying with the pack of otr traffic
engine temps were pretty normal...fan kicked in as expected and kept the water in the 195 -208 range, but the tranny temps slowly climbed to 202 then would regulate down to 197-198 then back up to 200 -202
it was so hot on the road, i ran both roof a/c units and the dash air for a good part of the run up.

as a rule of thumb i have used 100 degrees over ambient for a gauge of what tranny temps may be while running .

on the way back the temps were exactly the same and out side temps were 96-100
just curious if anyone else is having near the same temps
the pick is us loaded up heavy, with the hauler and the crewcab 150

[AFChap]

Don't know if you have Cat or Cummins, rear radiator or side. I presume Allison tranny...

I have a side radiator. My toad weighs around 4,200 lb. My 350 Cummins ISC tends to run in the 175-190 range, and the Allison tranny tends to be in the 175-180 range. Only on severe climbs will I see engine temp get above 200, and the tranny temp can also get close to 200 in that case.

You are pulling a good load. I suspect you have a rear radiator. You might check the tranny cooler to see if it is partially clogged, and maybe the radiator too. The rear mounted tend to need cleaning every year or two ...Simple Green or similar product seems to do a decent job.

[powerboatr]

thanks
its a cummins and a rear radiator.
i hosed the coolers off when we arrived up there to get the road dust off, might be a time now to do a deep clean

[Mr_D]

TranSynd lowered my trans temps about 20° when I changed from Dexron. OP: what fluid do you have? I very seldom see anything close to 200° now.

[powerboatr]

Quote:

Originally Posted by Mr_D TranSynd lowered my trans temps about 20° when I changed from Dexron. OP: what fluid do you have? I very seldom see anything close to 200° now.

it has transynd from the factory and only 12k miles on the tranny
tomorrow its supposed to be cooler so maybe a little climbing up and cleaning of the radiators is in order

[Mike Canter]

Spray those radiators with spray Gunk (original) engine degreaser and let them soak. Spray the Gunk from both sides if you can.

Let me also say that since the transmission fluid is cooled by the radiator and the engine coolant it has a tendancy to follow the engine temperatures.

[powerboatr]

Quote:

Originally Posted by Mike Canter Let me also say that since the transmission fluid is cooled by the radiator and the engine coolant it has a tendancy to follow the engine temperatures.

the engine coolants temps imo are a bit high but have always followed the below since it was new.
it will run up to 210, then the fan kicks in and the temps will fall back to 185 ish, then the fan kicks off and the temp will slowly climb back up to 210 and the cycle begins again
i may call cummins and see if there is a ecm reflash to lower the cut in temps.
i am sure it is higher because of the exhaust after treatment DPF

thanks

[powerboatr]

Mike
on saturady evening i had #1 son wiggle up and around the radiators and clean them........WOW did he get allot of black gunk and sand washed out from the engine side radiator.
then we blew em out to dry and soon a trip to see if it helps any

thanks

[Mike Canter]

Did you spray it with an engine degreaser? Hope so because if you don't wash that oil off it is going to get dirty again real fast.

Let us know if it cooled it down.