anyone know what controls tc lock up? Mine wants to lock up immediately after going into overdrive. All other tc lock ups are normal 1-2-3.

2003 ram 3500 drw h.o. eng

It has also developed a hunt between 1-2 with light throttle

clean fluid & band adjustment

 

In regards to part of your question ,I have an 05 3500 and the hunt turned out to be the governor pressure solenoid in the tranny valve body. There was a tsb on mine. Once this was changed, no more trans hunt. Roger M.

 

Lockup is controlled by the ECU. Locking up immediately after goig to OD is normal. Lockup strategy is much more aggressive in TH.

The shift hunt is a pretty common problem on these units. The governor solenoid and transducer is the usual culprit. Change both when it is done. There is a TSB for this so if you are in warranty and complain loud enough you may get it done for free.