Hi, I have a 2010 F-150 that I use to tow my 23 ft trailer. The trailer weight is approx 4300lbs. Last weekend, coming back from a weekend of fun, everytime I started climbing a hill, my transmission, would downshift and "clunk" extremely hard. When I say "clunk", I mean the whole truck would jump forward. I don't know if I'm not driving it right, push it too hard, or if there's a problem with the transmission. I live in Colorado, and go to Moab, Utah quite a few times a year. My elevation goes from 5345' (home) to 4700 (Moab). There's no problem going from home to Moab, coming back is the issue. I also always the tow/haul feature. Does anyone have any ideas? I love my truck and hope there isn't a serious problem!

Becky

 

It may be time for a tune-up. I tow a trailer with my 97 F150 and had the same symptom. New plugs took care of it.

 

What engine do you have and how many miles are on it?

 

Not very likely that a 2010 has that many miles on it yet.

If it's a 6 speed auto, it may need a software update. Discuss this with your dealer.

 

It has approx 44000 miles on it. I just had the transmission serviced (flushed) last week. I remember awhile back when I was having the same problem, the dealer said something about the computer needed and update and they did it, but I wasn't sure if that was really the problem or not!!

 

It's a V8, 4.6l engine. I'm not sure if it's the smaller 4.6 or the larger one.

 

Take it back to where the work was done...presume a dealership in this case.
You should be well within the warranty range/timeline. If this so called "update" is the culprit then the dealership has to be aware of potential issues as well as Corparate

Explain what is happening and tell them to make it right. What you've done should not be out of the realm of "normal driving" for your truck.