I just took a 500 mile trip and my trans started acting up. Everything will be going fine then the trans temp and O/D off lights will flash while my trans downshifts. It only lasts a 1/2 second then everything returns to normal. I tried to pinpoint what conditions cause it but it is completely intermittent. Any ideas?

 

Start by pulling the codes and see if that will lead the correct direction. It sounds like a bad connection somewhere and the trans is going into limp mode. Check all your wiring connections to the trans and the harness for chafing.

 

will it have codes even though the check engine light never came on?

 

If there is a fault code it should be stored. The ECU will store faults and not turn on the MIL if it is a transient problem. You just have to check.

 

If it is a diesel the problem can be the cable between the engine computer and the computer on the transmission. Check to see if the connection points are corroded at the transmission. There was a recall on this connection problem several years ago that the pin connection on the trans allowed water to get in. If this happens it can cause erratic transmission functions and it usually will go into the limp mode. Sometimes if it sits overnight the computer will clear. It will eventually not clear and Hello Shop. I had this problem with my '03 dually diesel. Another issue is if one of the wires in the cable between the engine and transmission fails or breaks. It took Chrysler engineers and a very smart technician at the dealer to figure this out on my truck. No problems since then.

 

Thanks for the input. I'll check those things out after work.