We took our 8000lb 28 foot fifth wheel on our first venture with our 2015 Lariet 6.2 with a 4:30 rear end. Some very interesting changes from towing with a 2012 F-150 Ecoboost the last two years. The truck was very stable and didn't really seem to notice the trailer while driving down the road. That was quite nice even thought the ride was still a bit bouncy. What was very odd was a shudder in the rear end when starting up from a start. I think that might of been from the tires slipping. The pin weight on my trailer is only about 1400lbs which may not be enough to anchor the tires starting up with the 4:30. The other oddity was using Tow/Haul accelerating on an entrance ramp, the motor rpm was really high and the acceleration was not that great. I could not seem to coax it up in gears in drive, I did not try manual. The Ecoboost pulling the trailer would have left it in it's dust. I'm sure this motor has the same or more guts than the Ecoboost had. It just would not apply it. It was as though the truck thought I was pulling twice the weight. I did not have a chance to duplicate the freeway entrance with the Tow/Haul off, but I will definitely give that a shot next weekend. Just wondering if anyone has more suggestions how to best tow this trailer...

 

Turn off your Traction Controll and see it you still get the start up shutter.

 

The only time I use TH is when I come into small towns on two lane roads or maybe slowing down coming off freeways. Any other time I just use drive or manual, it just wants to hold the gears in TH and slows down the acceleration but it works great for slowing down by down shifting to aid in braking.

I'm not sure what the shutter is but when we started pulling with ours with 370 miles on it we did have some until we beat some of the new out of the springs, we run 3200 to 3400 on the pin.

Denny

 

I thought maybe the TH was too aggressive for the load I was pulling. I do like the engine braking it provides. I will try using it on demand and see how that goes. The springs could be a little stiff right now giving me that start up shudder vibration. I will try turning off the TC and see if that effects it.

 

My guess.
Either your back end is squatting and you are getting driveline vibration at startup, or, if your truck is sitting level, you are getting axle wrap. IMHO. Airbags will fix the squat, and some form of traction bars will fix axle wrap.
Is the 1400 pin weight actual from a scale, or just estimated from the mfgr specs? It could be that you have more actual pin weight than you think, causing your truck to squat?

 

The dry pin weight is 1089 lbs. I am going on what others have weighed in at with a full tank of water. It really can't be exceeding 1500lbs. The squat is very minimal with the truck and trailer level loaded with a full tank of fuel. I was quite impressed with that. I had Roadmaster Stabilizers on my F-150 and they really made the rear axle behave. Maybe I should consider putting a set on this truck. They eliminate any spring deformity by holding the arch in shape.

 

I have basically the same truck. f 250 Long bed xlt, 2015, same axle. 5er about 9500 lbs loaded. Have not noticed any of what you experience on take off. Tow haul holds the gear too long and though I mostly keep it on and turn it off on take off and on any hilly terrain. same with cruise control. Use the button shifter on the column. It works great. use it to down shift. I believe you could buy this truck for less than a half ton ecoboost. I bought this truck because I wanted raw power, no turbos, beefier than a half ton, better brakes, larger better tires, etc. Takes years to really prove out a truck, so imo, the ecoboost still has some time to prove itself. and yes, it is odd now that the half, 3/4, and one ton all seem to have about the same payload. The main difference then is in the springs, brakes, axle size and ratio, front end, alternator, starter, and who knows what else. To me a half ton truck is still a weekend warrior vehicle and fancy grocery store truck/car. pin wt. about 1500lbs

 

Update as OP: All is well now. I have addressed some of these issues in another thread but here is a synopsis. I was towing with the hitch too high. The hitch I was using had the highest lowest setting of any hitch available. The dealer aggressively looked the truck over and could not find a problem. They offered a free appearance kit installation which I declined because I thought it would make matters worse. I asked them if I could buy a factory Reese Elite hitch at cost and they compiled with my request. I installed the hitch hookedup, and the squat all but disappeared. I had a wandering problem that was corrected by a caster adjustment. An engineer suggested the start up shudder was caused by machining marks left on the drive shaft spline. He said it should disappear by 4-5000 miles and he was correct. I added Stable load wedges and every thing is level and towing great. I was considering air bags but now find them unnecessary.

 

I have had my new 2015 f350 for about 6 months.. and I hate the TH trans feature.. rev's engine much too high.. it likes to go into 2nd gear when it is really not needed.. I find using the "manual" shift mode much better when pulling my 26 ft Arctic Fox.. no shutter here..