Hello. I have a 2010 F-250 super duty with 105000 miles. Been having an issue recently when towing a horse trailer in tow haul mode. Every so often upon acceleration it is as though it gets stuck around 40 mph won't accelerate and won't change gears (gets up to about 2500 RPM). Once you slow down or stop it will reset and be fine, but might do it again later in the trip. No warning lights come on when this happens but it sounds as though the truck is in limp mode based on what I've read. The truck DOES NOT do this when towing without engaging the tow/haul mode. Any thoughts on what we are dealing with here? Not feeling like dropping thousands to fix. Might be time for a new truck. But I thought diesels were supposed to go 200k miles!

 

Probably not the cause since it only happens in t/h, but step one for transmission issues would be to check the fluid