I have a 2013 f150 screw 6.5 bed. I bought the truck and was happy with it tell I loaded it with a half load of wood and I shuddered from a start very very badly. All the dealers that I have called seem to be beating around the bush and say that they never herd of the problem. I think this is crap because there are 1000s of post out there saying that it is a huge problem with the ford and it has been going on for years. one dealer said try putting on air bags. most of my research says this wont help. last week my local dealer said he was ording some shims for the rear end. I called this week and he said sorry there are no parts kits for the shims. I am starting to think that I wish I went with something else. the shudder is so bad that I know that it cant be good for my truck. why wont ford fix this problem if it has been going on for so long. All the resurch I have done says that RAS kind of fixes this. wish ford would fix this.

 

I'm confused, is the truck "diving under load" or did you mean "driving under load"? If it is diving, then there is an issue with the front suspension, likely blown shocks/struts. If you meant driving, then the shudder could be a number of things. Have they checked the transmission? Shudder under load can be a trans issue, or slip joint.

 

Driving. The shudder is horrible under load from a dead stop to take off. The only thing they offered to do is to put shims in to change the angle but said it might shudder unloaded. Then they said they couldn't get the shims then never called me back.

 

That sounds like a dealer that doesn't want to find out what is wrong. I would load the truck up so that the symptoms are there, go down to a different dealer, and take the service manager or technician for a drive.

 

I think that is what I am going to do. I have supper crew 6.5 bed with 3.31 gears. Do you know the numbers that I can load?

 

Look at your gvwr on the pillar sticker then swing by a scale to be weighed. I would not suggest heading to the dealer heavier than your gvwr.

 

Sounds like axle wrap. And yes it's a known problem and most people have found that RAS fixes it.

 

I've had the same thing happen a few times. Every time it was an extremely heavy load in the bed, no trailer. It only shuddered from a dead stop until it got moving. The mechanics at work, electric utility company, all seemed to think it had something to do with 1 - the aluminum driveshaft and some flex in it, or 2 the length of the driveshaft and the third u-joint. All in all they weren't at all concerned. Nor was my local dealer. I've had the truck for 3 years and 50k miles. I'm no longer concerned.

 

This^^^^

Yes it is a problem for any vehicle with really long, soft leaf springs and lots of torque multiplication from the transmission. The two-piece drive shaft doesn't help things any. I've seen this on many fords all the way back to the 80s. Some rams with the cummins have it too.

That being said, my truck had it bad loaded too. I installed the RAS and that took care of about 85% of it. Still have a little of it but not near as bad.

 

Axle wrap. My 2011 does it loaded or not but much more noticeable when loaded or towing. The air bags nearly eliminated the issue when unloaded but did not affect the axle wrap when loaded/towing. I got the same response from my dealer.