BY JIM BIGLEY

IN TOUCH

I’m the original owner of a 1998 6.5L 3500 truck with 410,000 miles. That’s a lot of experience with this truck, so I can hear or feel everything. Over the years my transmission has been revving out of gear while on the highway. It’s usually fixed by disconnecting both batteries for five minutes to reset the computer controls. If it happens again, I have my batteries tested. A bad battery is usually the cause. Another issue involved my radiator thermostat running my truck too cool. A new thermostat fixed it. Now it drops out of overdrive randomly and then goes back in. My batteries are good—I’ve done the disconnect trick. My thermostat has me running at a good temp. I know it’s got 410k miles, but could it be the transmission module? I’m open to any suggestions. Thanks, John Williamson

Hi John, Two things you can do today: 1. Have the trouble codes read, and then let me know what codes (if any) are being set. 2. Service the transmission if it’s been a while—say more than 50,000 miles since the last fluid and filter change. Look for a more than normal amount of sediment or metallic/friction disc particles in the transmission oil pan. There will be some, but the amount is the issue. If you’re in doubt about what amount of sediment might be normal or abnormal, send me a photo if you can.