So l have 99 1500 2wd with the 5.9 gasser .
The problem I've had the last few weeks is the thermal clutch fan wont release and " freewheel" it wants to stay constantly fully engaged even at 4k .. I've went from about 300 miles to a tank down to 190 ish .....

grant it I know the trans is acting up and wont downshift properly and upshifts early since the bands got adjusted ..

I've tried replacing the clutch fan twice and the thermostat and it has a 195 in it and still no difference ... Its never gone over 200 since I've owned it.. the upper radiator hose is HOT like it should be and the lower is warm. And both have good pressure in them ..

I've got a temp sensor in the trans pan and it only gets about 120 so its not like that's too hot causing the fan too be constantly engaged

Could the radiator be partially clogged but not enough to cause it to over heat.. I've got a temp probe by the top radiator hose and the hottest that's read that I've noticed is 160ish

Any input would be helpful.. im about to just goto dual efans from the dyi links as im stumped now

 

I believe it takes a little while for a new fan clutch to break in to the point it more or less freewheels under normal conditions. How long have you given the replacements?

 

About two weeks its only freewheeled once within 500 miles and that was for about 5 minutes .. even when I shut the truck off it don't coast to a stop its like its a direct drive fan and snaps to a stop

 

Try and turn it by hand. See how it feels.

 

There is alot of resistance, I used to be able to hold the blades when it would freewheel and it wont let u do it now.. but all 3 that I've tried feel the same

 

were all 3 that youve tried from the same manufactuer?

 

All the local stores carry the same manufacturer... imperial or something like that