I did some testing over the long weekend when I went camping. I camp in the mountains and have a lot of opportunity to test my rig. This weekend I put a thermocouple in the water at the top of the radiator and another on in the air stream between the rad and the fan. When I was pulling the biggest hill on the trip I paid close attention to the temps. About half way the fan clutch kicked in at a brisk 220°F. Speed was about 52 mph. At 3/4 of the way with water temp sitting about 215°F the torque converter unlocked, at 45 mph, and the fan clutch dissengauged. At the top of the hill the water was 233°F and I was down to 40 mph. I was also watching EGT's they never went over 1000°F. They used to go higher untill I took the "meow out of the cat".
I know the temp is high, but this is also the hottest spot and the water feeding the engine is lower. Also I noticed that the temp of the air stayed fairly low untill the clutch kicked in and the air temp went way up, 200+.
So on to my questions, does anyone use a torque converter locker, if so what brand? Why would the fan clutch disengauge with the water temp still so high?
I have cleaned the area between the cores, but last fall. I haven't check it this spring yet. Will having the core rodded help any?
I don't have a tranny temp gauge yet, just got the 3 gauge pod. I know that when the torque converter unlocks there is going to be a jump in temp. So at 40 mph what do I do? If I am in 3rd the converter is unlocked, if I am in 2nd the rpm is too high, and slowing down in not am option. Will a converter locker help to solve this problem.
About the fan, I was thinking of putting a small fan between the rad and main fan that is right in front of the clutch. When the water temp hits 210°F the small fan comes on and blows hot air across the clutch and makes it engauge. And hopefull keeps it engauged untill the water temp falls low enough. Good idea, bad idea?

Thanks for any replys.

I bet a quality aftermarket clutch would perform much better, and not unlock when the engine is still hot.

On my 99 the fan is very noisy at 200 degrees, and stays that way, i bet it is close if not fully locked up. I have a factory clutch.

Kennedy sells a high quality fan clutch, the same test with his clutch would prove money well spent.

Oops, I just noticed your sig, you already have an aftermarket clutch. Maybe since yours is a 95 you are just not flowing enough coolant? Is it possible at 45mph the heavy clutch is properly cooling the radiator enough it spins down while still overheating?

I have noticed on my truck the higher the elevation, the longer it takes for the clutch to lock up. My clutch works great at sea level to around 6000 feet (Denver), but as soon as I get about 8000 feet plus, it waits longer and longer, and will release at a much higher temperature then at lower elevations. Must have something to do with the thinner air, or the lower barometeric pressure on the fluid, or the cooler air through the radiator , or maybe a combination of all.

Torque Loc will work on your model truck ( locks up TCC )

Also the resister accross the temp sensor will allow the TCC to lock up in 2nd, and 3rd,
and hold TCC locked in 4th untill a down shift occurs.

causion, Trans operates in high pressure when Resister is switched in.


I use 2nd gear TCC locked on the hills that slow me down to 40-50 mph range,
above that I downshift to 3rd before hill and lock up the TCC. No tran temp problems.
Also oil temp stays cooler in 2nd, as eng is not working as hard with TCC locked.

I have a BD Tork Loc and it works well to hold the tranny temp down. Note that the low rpm's are not good for the tranny clutch. It was recommended to me to stay above 1700 rpm with the Tork Loc on.

Took the front end of my rig appart last night. Removed the rad, tranny cooler, and oil cooler. Cleaned all cores, there was extreem amounts of junk in the AC core right behind the oil and tranny coolers. Rad had tons of crap in it. It took almost two hours just to clean the cores. Removed the vaccuum pump while I was in there, and added a drain hose to the radiator. Now I shouldn't have a problem with heat, I am just supprised it was keeping as cool as it was on those big hills. I did notice that the tranny cooler is kind of small, I think that I will be putting in a bigger on in the stock location. Stock cooler is about 6" X 10".
Also replaced the belt with a shorter one. Stock belt 101" new belt 100", took two tries the 99" was just too short.

After towing this weekend, couldn't get the temp over 200°F and I was trying to. Wasn't pulling the Travel trailer only a couple of motorcycles. So far it has made a huge difference cleaning the cores out. Will be pulling the TT this weekend again and will be able to tell the real difference.