The other day I was driving home from work and my trans temps started to spike in the 220-230 area. I made it home and used IR thermometer check the pan temp, it was high also. I felt the coolant lines going into the radiator and remote trans cooler, they were both cold. Then I felt the trans coolers lines that come right off the trans and they were hot, but after the thermo bypass valve they went cold again. So basically I figured out what is causing my stoppage in the system. I replaced the valve and flushed out the lines with a can of trans flush and compressed air to make sure there wasn’t a blockage in the system further down, as was well.

After getting it all back together and fluids topped off I took it for an extensive road trip, it seemed to be working alright, temps were sticking in the 160-170 range a little higher then I usually run. I did feel the lines throughout the system and they were pretty warm so I felt confident that the system is working well now. Well I guess I was wrong because this morning I took the truck to work thinking as is well, my temps spiked to about 200F by the time I got to work, after I parked I popped the hood and checked the cooler lines, they were cold.

I would like to know if there may be something I’m overlooking or I received a bad valve. I need to take my truck on a 3 hour trip tomorrow and I was thinking about taking apart the old valve and plugging up the bypass port so I know for sure that fluid is being ported throughout the system.

Thanks in advance.

 

There is a gent who goes by Mark Kovalsky who is a retired Ford tranny engineer...very knowledable...do a search and I'm sure he can give you good, solid guidance.

 

You might have enough junk in the trans fluid to keep sticking the valve. You could block the valve in the non-bypass direction. The valve is there to warm the trans faster, which improves fuel economy.