I was driving my truck to work Tonite. All was well, I hit a dip in the road at 55mph, that shook the entire truck. About 20 seconds later I get a check engine light, and the transmission slams into a lower gear. I pull over immediately. No visible leaks in engine bay or under truck. Check trans fluid, which was still clean and full. I check codes and got p0700 power train transmission control system, p0750 powerrtrain shift Solenoid a, and p3230 power train. I cleared codes and the p3230 will go away but comes back. The other 2 are steady. So I decide to turn around to go home. Truck felt like it was stuck in a higher gear maybe 2nd or 3rd from a stop. And does not shift. Truck was doing about 2600rpm at 50mph(which I would assume would be 3rd gear) Got home, check for leaks again which there were none. Checked transmission dipstick, fluid still clean and full. Felt the transmission cooler, and it was still relatively cool to Luke warm, so wasn't getting hot or anything. Shifts into reverse fine, and acts normal. Just drive seems affected, although truck will down shift into 2nd if shifted lower via the shift lever. Doesn't seem like it will go into first though.
I need help PLEASE. I'm relying heavily on my truck now during the winter season. As I have a summer car that's put away.

 

Forgot to mention the truck has a 5.7 hemi and the 545rfe trans

 

Sounds like limp mode. You can check the main transmission plug if that shows to be fine, replacing the electronics in the transmission should fix your problem.

 

Ya, nothing looks out of the ordinary plug wise on the transmission.
I've also called a few transmission shops this morning, and they're all pointing at the solenoid pack.

 

Have you tried disconnecting the battery for a while, to completely reset the system?

 

Without proper diagnosis anybody can throw stones hoping to hit the target. Do what HeyYou said first
True this first. Does the trick with the 2nd gen transmissions work with the 3rd gen's?

 

Yes I have. It will allow me to clear the codes completely this way, but as soon as the truck is put in gear, the codes come back instantly

 

Check the connections then. If that doesn't help, time to take it to your local trans shop.

 

Connections all seem pretty secure. I've called 3 different transmission shops, and they all said the same thing. The solenoid block, that's on top of the valve body. So I ordered one if those. Fingers crossed

 

in case anyone else sees this thread, and was having issues like me. i was able to put a new shift solenoid pack into my truck, and it fixed it. rockauto calls it a kick down module. but most places call it a shift solenoid. it comes in a big plate, that bolts on top of the valve body.