khogle2-
I agree with you 100% about this being a pinion angle issue. I have an '11 FX4 EB SCREW 6.5' bed and have a slight shake immediately at take off from a dead stop. At very, very light accel not noticeable (read: not enough spring wrap to change pinion angle), however towing my 7700lb. travel trailer this weekend at times between 45-65 the truck would develop an ungodly vibration felt throughout the entire truck! If I would decel/accel it would not change, however if I attempted a cruise speed where there was little or no torque to the rear end the shake would subside after a few seconds. I think that due to all manufacturers trying to make their trucks ride likes Cadillacs with these mushy rear springs there is no way to completely eliminate this issue without some major design changes!

Upon getting home this evening I immediately ordered a set of Air Lift springs to help level the truck loaded and to try and keep the drive angle closer to tolerable. I am also going to keep an eye out for a well designed and well tucked in set of traction bars designed for these trucks. A set that is built correctly should maintain pinion angle at ANY ride height and eliminate any pinion angle changes that would cause a shake.

Does anyone remember back when the '92 - '96 F250-350 SCAB Long beds had a TSB out to replace the carrier bearing mount bracket with a longer one to correct the drive line angle? This is much the same EXCEPT there is only so much that can be done with the huge range of motion and wrap the long, mushy springs on these new trucks allow. The only way to 100% alleviate it AND still have the super cushy ride is to add a traction bar/torque arm OR go to a multi-link rear suspension like on the '09 - up Dodge Ram 1500. I really think this may be the next big move by the other manufacturers on these trucks! Dodge just sucks at engineering or they could have already spanked everyone on ride quality and towing ability if they would have done theirs correctly.

All this being said, it still very much disappoints me that Ford's engineers (with ALL the durability testing they supposedly do) cannot put a truck on the road with these very fundamental leaf spring issues in check! I paid almost 50K for this thing and still have to resort to the aftermarket to be able to comfortably tow 7700lbs with a vehicle that is rated to tow 11,000lbs!! THAT is BS.... and I am a diehard Ford guy!!

To everyone having dealers replace valve bodies and clutch packs and/or reprogramming for the shake from a dead stop.... NEITHER ITEM WILL DO ANYTHING FOR THIS ISSUE! IF you are experiencing a shutter when going from 1-2 upshift or 3-2-1 downshift THEN and only then will these fixes have an effect on the problem. I believe there are several people posting different, but similar "shutters" under this thread and they should be separated.

My two cents worth.

 

Check out the CalTracs bars, lots of our guys are using them at the track. They're adjustable for preload & pinion angle adj., no wrapup with them. I may go to them after Ford gets through messing with my truck.
Check out the picture of them on their site: Calvert Racing - The Leader in Leaf Spring Innovation




I am also going to keep an eye out for a well designed and well tucked in set of traction bars designed for these trucks. A set that is built correctly should maintain pinion angle at ANY ride height and eliminate any pinion angle changes that would cause a shake.

 

Rancheroracer-
Thanks for the link! I like those, but I am kinda interested in more of a torque arm setup. Something that doesn't limit travel, but keeps the pinion angle in line. Have you ever seen the torque arm that Chris Alston Chassisworks makes under the Total Control Products name for classic Mustangs? They bolt to the center section on a 9" housing and attach to a cross brace by the tailshaft of the trans and the short link is adjustable to set pinion angle. There is a perfect spot on the frame of these trucks by the carrier bearing to attach it to, but it would need to be stout with the extra length needed and a different attaching system on the housing would need to be designed. Anyone know any good engineers? NOT the Ford ones! Lol

 

Coupe,
Good thought on the torque arm.

The CalTracs don't limit travel like normal traction bars do since they have the roller & pivot at the front spring eye.

 

Rancheroracer - Is your truck being worked on right now? You mentioned earlier that Ford is replacing your leaf springs. Please keep us updated on this. You are getting farther than I have with my dealer!

 

They're supposed to call me when the springs come in, I'll post when something happens.

 

Just curious if any of these truck having problems have the MAX TOW package? Do they have the heavier springs than the standard tow package?

 

Pinion angle jives with what I saw. I actually created the problem by altering the pinion angle with longer rear shackles design to drop the rear by 2 inches. I still like to lower the rear inline with the front for a number of reasons - but not at the expense of a vibration or reliability. Good luck with the troubleshooting/dealer fixes.

 

My 11 eb xlt screw 3.55Ls 18"wheels 2900 miles, is doing the shudder at take off( I took to dealer, they agreed it exsists, which is a good start. But they said they can not do anything until ford releases a TSB for it...I said if it doesnt come soon that they will need to try something! Supposedly they said ford is aware of the issue happening with alot of trucks and is working on it. But my truck was the first they have seen with it...The mechanic said he took a brand new truck off the lot for a test drive and it did same thing, almost insinuating that its just how it is. I finally got him to say out loud that its not right, i had to actually stop him from twisting words and come out and say that its an issue lol. Would have thought he was trying to sell me the truck himself or something, I mean come on man admit the issue work for a fix and help a hard working slob the f out!
im going to be calling them once every two days until they start throwing things like leaf springs, drive balancing, and whatever else they can try.

Mine is very very slight with an empty bed but add 500 or so lbs and its very noticeable. Loaded down for camping id say we had about 900lbs back there and it could have shaken a tooth out np. I have not towed anything but im imagining its even worse. It maybe just happenstance but it seems to be better with a full tank of gas and worse at about 1/4 of a tank.

So here is my question: What else is this shudder screwing up while i wait for a fix, and what else can i do to get them to try and throw fixes at it while I wait for this mystery TSB? Is it so pressing an issue that i should demand a fix, I just dont know what to do, never had an issue like this and im no mechanic.

Seriously stuff like this makes me wanna take a sleeping bag and a video camera to the dealership and tell them ill leave when my truck is fixed.

Arrrrggghhhhh.

Love this freaking truck tho, But i also seem to fall in love with crazy women so my love radar aint so good.

Oh and just the regular tow package NOT max on mine.

 

guys i just had my drive line replaced from the original two shaft to a single shaft man what a difference smoooth no shutter any more

 

At the dealership?

 

I went to my in town auto shop and they referred me to a drive line shop the told the same story i told them about a guy in Arizona had the same problem. they took my truck and did the job. my truck is a 2002 f250 superduty crewcab short bed and is lifted 8 inches with 37 inch bfgs tires. talk to ford about a drive line specialist see what they say

 

Any updates guys? I have a 2011 Ecoboost long bed super crew with Max tow. Experiencing same acceleration shudder from a stop described many times over above. I have been putting off going to the dealer until a solution becomes apparent. Honestly, though, it really doesn't bother me, except when towing heavy load. Its one of my very few complaints with the truck. Overall, extremely happy!!

 

Dropped mine off today, engineering wants to try different rear springs. I'm pessimistic that will fix it, I clamped the springs as a test & shudder was still there. They didn't want to do the two TSBs for driveline/slip shudder I found. We'll see..........

 

Ranchero-
Keep us in the loip. Will be interesting to see if Ford does anything to fix it. I have started to notice a high pitch clink noise when shifting from reverse to drive occasionally now. Sounds like an old truck with a u-joint going bad. I have 11k miles now. Seems kinda early for that don't you guys think?? Love EVERYTHING about this truck other than the rear driveshaft and rear springs!