Hello everyone, first and foremost I have a 05 dak 4.7 automatic 2wd. Ive owned the truck since last Nov. Since then Ive changed all fluids to synthetic, which includes new tranny fluid. I also installed superchips tow tune as well.

Now to the problem, before the weather turned warm here in TN, the truck ran fine. Since temps have rose to low to mid 90's the transmission downshifts hard and seems confused as to which gear to stay in while cruising.

I can tell something is wrong, just not sure HOW wrong lol.
Any and all ideas/suggestions/similar experiences welcome.

 

Ive seen troubles like these when something is up with the tranny fluid. I'm not entirely sure how switching from stock tranny fluid to synthetic affects transmissions. But I have heard stories saying that you should not change your tranny fluid after you reach 60k mile (also not sure how valid this is anyone's input would be nice). but it sounds like you only have the problems when the fluid gets hot. I would try looking into a transmission cooling system.

 

Had similar problem with my 05 dak downshifting hard then throwing codes ended up replacing trans shift sylnoid cured my problem but also added a transmission cooler as well easy install

 

Disconnect the batter for an hour or so. Known to cure many an ills on these trucks...

 

I would try disconnecting the super chip and see how the transmission shifts or replace the fluid with factory ATF+4.

 

Yeah I guess it would be wise to reset it back to factory tune just to be sure. Is there a trans cooler that you guys recommend over others?

thanks for the recommendation jkeaton, I did that exact thing to try and remedy a airbag light comin on in the dash every now and then.