Well, since I changed my ATF with the Royal Purple, my hard down-shift (4-3rd or 4th-2nd not totally sure which) issue SEEMED to become a NON-issue. However, we've gotten some nice chilly weather here in Denver over the past couple days, and now it seems to have reered it's ugly-@ss head again. Wondering if there could be a prob with the tranny that I'm not seeing.

 

The more threads I peruse, I see people stating that the AT's won't allow a shift into 4th until a certain temp is reached. I can say without a doubt, that mine shifts into 4th without any concern of temp. Last winter, -10 just started, if in D would go to 4th before the engine had even THOUGHT about warming up. Could it be the Tranny temp sensor? Could that be causing this issue, or would most likely be the coolant temp sensor below the manifold???

 

Thanks for any and all help. Hey nipper, long time no read.

I wonder if your TCU is b0rked. That controls when the 4EAT shifts...

What year and model is your car? I may have some info for you..

 

Matt