Hot!!!

A few ideas:

check the radiator coolant level & proper mix of inhibitor levels. clean the radiator. (has the engine cooling fan been turning on more than normal). How old is the coolant.

The transmission fluid may need to be changed and/or the transmissions oil cooler (under the chassis small radiator) may need to be cleaned, perhaps using a degreaser. How long ago was the fluid changed.

 

i would check the inhibitor levels just the same. What about the Transmission Fluid, how many miles ago was this last replaced. (when was the oil cooler fins last cleaned)

 

This & That; recheck the fundamentals first. (possible thermostat sticking).

The heat may also be coming from the transmission. (as u stated, its spread to the drivers side.)

 

I only do it when I'm in Iowa.

 

If it just started,I'd look for cracks or a firewall seem opening up.

 

If its a twin stack, it runs down both sides-splits right in front of the tranny. Exaust would be my first check point- single or double stack. Tranny could be getting too hot? that's one thing I used to like about the old trucks- they had gauges to tell you if your tranny was too hot or if your rear ends were getting too hot, a guage to tell you if your Turbo was getting too hot. Insulation could be getting too thin under the floormat?

 

your not allowed to wear open toed shoes while operating a cmv per the fmcsr. how ever it's the one they never do anything about.