So I've been having an issue with the 2nd gear search in my 2007 5.9. I was resolved to changing the solenoid in the valve body since that seemed to be a common solution. Well the other day when I had a scanner hooked up the truck struggled a bit to restart. So over the weekend I decided to install two new batteries. When I was doing this I noticed the one battery had leaked up a bit on the cable connector so I cleaned it up and installed the new ones.


Guess what??...Second gear search is gone!! Truck seems to run quite a bit better also. Now realize the truck started fine every time before save for that one time. So if you are having an issue with a 2nd gear search I highly recommend checking battery voltage and condition of the batteries first.

 

2nd gear search ... are you talking about the transmission slipping until engaging into 2nd gear?

 

I made the same observation when I changed batteries two weeks ago. Also getting about a mile more per gallon of fuel.

 

That surging going from first to second

 

Does anyone have an explanation of why old batteries could cause these things?

 

My guess, it wasn't the batteries, when the batteries start to weaken you lose accessories such as radio.

What I think happened is when you changed the batteries it caused the PC to lose it's memory which forces the PC to relearn your driving habits in regards to shifting/throttle position, etc. I bet it will return before too long.

 

Yep, you called it. Mine is back to its old tricks

 

Sorry to hear/read that.