I'm trying to collect anecdotal information on problems with the CBV (coller bypass valve) in '04-08 F-150s... and others. A few sources (not "A" list sources but sources worthy of some note) claim this valve is notorious and will stick in the bypassed mode, which will allow lube flow but a hard worked tranny may overheat because the coolers are bypassed. I wonder if any on this board have anything to add. Personally, I think a CBV is a good idea because warm oil is happy oil but if the unit is unreliable, I want to know now before mine fails so I have time to find an alternative. Fortunately, I closely monitor trans temp, so it won't take me by surprise.

 

Well, it's not a by-pass valve even though it may be called a CBV, it's a thermostat, and I've never heard of one failing. The only way to know if it ever did though would me through monitoring fluid temps and getting a feel what's normal in order to recognize what's not.

 

To be pedantic about terminology, they do call it a "Cooler" Bypass Valve, because it bypasses the coolers, which would be different than a simple "Bypass Valve." Perhaps we should correct Ford's terminology to, "TCBV" or Thermostatic Cooler Bypass Valve."