Dual screws single drive load transfer question.

Even if you engage it, it will not work above 40. As far as diagnosing it, I don’t know. I’d have the dealer check the code and start from there. That system isn’t high tech, it’s just valves and fittings, actuated by the ECU.

 

If you wanted it to work at speeds greater than 40, I wouldn’t do that unless you’re empty or very lightly loaded, but you could turn the system off in your ABS ECU, add a switch on the dash, and a fan solenoid on your frame somewhere, and could control it manually. That’s how my truck is set up.

 

A tag axle will wear the outer edges off on a low rolling resistance tire. Even more so if it’s a drive tire on the dead axle. You need a trailer tire back there. The Hankook TL21, Michelin XOne Multi T (not the energy), and the Yokohama 114R, are all good choices.

 

I know this doesn’t help the current situation, but make sure your next truck is twin screw, problem solved.