Engine/Transmission (1998.5 - 2002) Runs "hotter" while towing?

[TowPro]

Last night I towed my 10K 5th wheel for the first "real" tow with my new truck (02). The PA turnpike on the East side is just rolling hills. So I am cruising along at 65 or so MPH on cruse and I noticed a couple things.



Even on rolling hills, the Converter stays locked solid in OD. (which is a good thing)



The engine runs around 180 deg on the flats, but as soon as I hit an incline (rolling hill) the temp climbs up to around 200-210.



I don't like this, the only time my 98 did this was when the thermostat started only opening 1/4 of the way.



Now from what I learned, An auto trans should only be producing heat when the converter is unlocked, but that was not the case in this test, its locked in OD, and the cruse is applying about 1/2 throttle when the temps start to climb. The outside temp was around 50 deg.



I am thinking it could be my Bug screen thats made out of standard fiberglass window screen, that covers everything behind the grill? OR could this be the symptoms of that TSB for changing the thermostat because of noise while towing? My truck has a build date of late summer 2002, so its right in that TSB range.

 

[jeepit]

I had the same problem last weekend while towing jeep on trailer. I had to take bug screen off since it was running about 200- 210 on hills at interstate speed and i did not feel good about that. Does anyone know if 210 is ok? I took shield off and it ran cooler the rest of the trip.

 

[JPLB22]

TowPro



My truck does the same thing. I was climbing a long grade ( which when unloaded I can take at 80 mph easily ) with a 7000# trailer. I locked it out of overdrive and was doing 60-65 mph ( which is between 2250-2500 rpm ) and my temp went from 185 to 210 pretty fast. I too am wondering if I am doing any damage???



P. S. TowPro I checked the TSB location on this site for 2002's and didn't notice anything about thermostats. Did I miss it or did you get it from somewhere else?

 

[2ndgen2500]

i too had this problem a bit ago, but after putting in my magtec pan it has lessed, my transmission used to get hot when i would pull my equipment trailer, but since i put the pan on its lowerd my transmission temp pretty good along with engine temp.

 

[ToolManTimTaylor]

2ndgen2500 , Where do you have your trans temp sending unit mounted?



Temps will rise as the cummins is after all working a load up a hill amd sofourth so a slight increase I allways thought is normal especialy when soon after she cools down back to the normal 190's range. . Now if it goes from 190 -> 225 then yeah I would wonder whats up.

 

[Diesel Nut]

What was that TSB all about? My temps run up a bit on climbs towing also, but not real high. Bout 210, I think.

 

[2ndgen2500]

i have the 1/8" mpt bolt temp sensor in the drain plug, and the trans temp sending unit is mounted underneight the driver side knee kick pannel which now it looks like i will have to be REMOVING YAY!.

 

[ToolManTimTaylor]

The reason I asked is you were seeing a lessened trans temp and now it makes sense as you are taking the reading at the pan where the fluid has allready been cooled once by the cooler and is being cooled again in the pan. As opposed to closer to normal trans temp in the supply line. I run a double deep mag with amsoil and on hyway cruizin 70 I see 120*f it's RARE I see 180-200 and thats stop and go 85 degree stand still traffic crud. Thats why I chuck it in nuetral when in stop an go... ... more stop than go.

 

[2ndgen2500]

this is true tim, that is a very low temp i see about 135 on the highway, and im am running amsoil as well.