Do I need overhaul? Detroit 60 series 12.7

You need to avoid low rpm idling, will cause Turbo to slobber oil, as the bearing seal doesn’t seal up, also causes, bearing to go bad. If I remember correctly,when I had that problrm it was a bad parking brake switch, located on the parking brake itself,on the dash. .There are 2 or 3 air controlled safety switches plumbed into parking brake valve.Easy fix, Buy a new switch, change them one at a time, if no difference change it back, go on to next switch, till problem is fixed. process of elimination, I think the switches are all the same, dealer parts guy can tell you for sure, one controls low air buzzer, the possible 3 rd one? Ask the parts guy. Get a look at and a copy of the screen if you can from him. It may help but is probably a generic example. But, by changing them 1 at a time, you can’t mess anything up.

 

Au contraire, mon frère! Those pressures switches are a huge PITA to change!

 

Yes, the parking brake valve.take it loose or gain access from top, by removing top of dash, however you can access it on your Truck.leave air lines hooked up if possible, you’ll see 2 or 3 switches.They're about 2” round. They screw into valve. One of them is most likely the problem. I think it’s called parking brake switch, other one , I think is low air buzzer, 3 rd one? If there is a 3 rd, not sure. Ask parts guy. He can tell you. I think they’re all the same. Not sure. Dbl check with dealer parts dept. when you go to buy it.

 

Those switches are not all the same, even though they look alike...some are normally closed and others are normally open.
Get a diagram from your parts guy, and don't mix up the switches. Probably a good idea to switch them all out since you got the dash apart, they are fairly inexpensive. For mine, I believe it was a 22 mm socket, deep well...be careful not to overtighten them, that manifold is plastic and will crack.

 

I will say yes to that people count the millage but not the amount of time the truck haves ben on for the life of the engine

 

You’re right about that, low air buzzer switch, normally closed, opens at 65lb. Turns buzzer, light, off.Brake switch, normally open, hit brakes, closes at 5 lbs pressure, turns brake lights on. Parts Guy noted they’re stamped accordingly No, Nc with part #s, not always legible though.