Hello everyone, first post here. I have a 2012 f250 crew cab long bed. Has the 6.2 and is 4x4. To start from the beginning I bought this truck 3 years ago and have put about 50,000 miles on it since then. Currently has 180k miles. The truck is completely stock minus an extra leaf spring in the leaf packs, a ranch hand front bumper and aftermarket wheels. Since the day I bought it, it has exhibited a rather intense shake/hop starting around 55mph and getting worse up until 75mph then starts to smooth back out. I have ran 2 different sets of wheels/tires in this time frame and the issue has been the exact same through both sets. I have also put on new u joints, new carrier bearing and new shocks. This “hop” that it exhibits seems to be coming from the rear, it almost looks as if the bed is hopping up and down when looking in the rear view. Shakes the mirrors and any drinks in the cup holder. Doesn’t feel like the truck is out of control it just feels like I’m going over thousands of little bumps if that makes any sense, but only in the rear. I have a new complete driveshaft ordered to rule out any balancing issues with my original one but it does not feel like a normal driveline vibration. I have been trying to fix this issue for 3 years now so any help would be greatly appreciated.

 

Forgot to mention, the “hop” seems to get slightly better, but not go away completely, when towing a 7000lb horse trailer that’s normally hooked up to the truck. Due to this I was thinking it had to with the driveline angle so I added a 1/2 shim above the carrier bearing. This made zero difference. Again the truck is mostly stock so driveshaft angles shouldn’t be an issue but was just an experiment.

 

Yep, this is the infamous "rear end hop" that the 99 to 16s develop. Its an oscillation that sets up in the truck frame and wheel balance seems to effect it directly the most and also road surface as well.

For my truck, it is present between 45 to 50, then at 70 as well.

I will post more later.

Here's a TSB:

https://www.ford-trucks.com/forums/1...m_content=post

I'll have more info later.

 

Thank you! I saw that TSB and made truck did not have one. I made my own dampener and attached it to the same spot on the frame. Unfortunately it did not change anything. Is there something special about the one ford offers? From my understanding it’s essentially just a weight that hangs on the frame, and it absorbs/ transfers harmonic vibrations. I utilized an old brake rotor with some metal cutoff to get roughly the same weight as the oem one. Bolted directly to the frame in the same spot. Do you think dropping $600+ on the ford part would yield better results?

 

Anyone have suggestions?

 

It's a harmonic dampener, not just a weight. Must be free to move to dampen the oscillations.

 

Do you have any suggestions to making one so I can avoid going to the dealer? Would adding rubber isolators to my current experiment do any good?

 

I would recommend looking at the FORD OEM part and use that as a model. I have no idea of the durometer of the rubber FORD uses in their dampener, but from seeing YT vids of the OEM unit, it seems to move pretty freely.

There are other threads on the board about this and it is discussed more in there.

https://www.ford-trucks.com/forums/1...pping-tsb.html

https://www.ford-trucks.com/forums/1...49mph-hop.html



Here is the exact time he shows the device and how freely the weight moves:

 

If this isn’t the fix to my problem what are some other likely solutions? My vibration/hop is much for pronounced/violent than what that video shows and mine starts at higher speeds and carries out through about 75mph. It will shake the mirrors enough it’s hard to see out of them. I haven’t heard of anyone have the issue at that high of speeds. Up until 50mph it’s nice and smooth. Also, it’s hard to recall but I do believe mine has gotten worse over the last few years. It does seem that certain roads have an effect on it as well.

 

In the full video you can see he uses vibration sensors on each wheel. If you don't have sensors, use a gopro to monitor each sucessive wheel for what you are feeling. At 180K, you might have bad ball joints, etc. leading to death wobble OR some other vibration. Could be anything really - you just have to keep looking until you isolate it.

Or, take it to an alignment shop and pay them to diagnose the problem for you. Might be cheaper in the long run instead of throwing parts at it.

Even though you see the truck bed hopping, it would be best to rule out the easy stuff first. Have you checked out the center carrier bearing (if you have one), the u-joints, the rear wheel bearings, etc for excessive play or wear?

And to your original question on whether to buy the FORD OEM dampener, I would check and see if FORD might provide one for you based on your VIN under the TSB. If not, I'd still buy one to rule out the harmonic as your vehicle is the long bed and most prone to this particular issue.

Good luck and please keep us up to date on what you do and your findings.

 

Center support bearing is new, u joints have been replaced in last 50k miles (and made no difference after). A few tie rods have been replaced in the front end and no play is felt with the tires off the ground. The vibration is not felt through the steering wheel, it’s more so in the seats and body of the truck. It definitely feels like the rear end is bouncing up and down.

 

Just put in a brand new driveshaft with new joints and center bearing, it didn’t change a thing. While I had the rear end off the ground I checked the rear wheels for play. Is there supposed to be end play on these axles? As in pushing in and out should the tire move? I know on half tons this is normal but don’t have much experience with full float axles.

 

Went and picked up a digital angle meter today to rule out driveline angles as the issue. If I post results later today is there somebody that can help me decipher if they are good or not?

 

Here's a recent thread of mine from the 6.7 section. I had my buddy install my new tires on my factory 20 inch wheels without the pressure sensors, since he did not want to pre-install the ceramic balance beads into the tire before balancing. Care has to be taken to not get the sealer on the inside of the tire or this will create an imbalance when the beads stick to it. They have to be able to run along the tire freely and go where the weight is needed to dynamically balance the tires as the truck is in motion. For me, it was no big deal not having pressure sensors. I needed access to the inside of the tire, with a pressure sensor on you can't pour the beads in, so the beads are added to a small plastic bottle with a vinyl hose on the end that goes over the valve stem and the beads are carefully poured into the tire. Then a replacement filtered air valve core is installed which is bought from them.

https://www.ford-trucks.com/forums/1...r-end-hop.html

These 99 to 16 truck trucks are known for this issue, to which Ford had no answer but to come out with that frame "balancer" to try to minimize the frame oscillation which is felt by the driver.

I have dealt with this when the truck was brand spanking new from the dealer. Their answer was to add more weight. I took it to a tire shop owned by a tire distribution company who owns and who I was good friends with the warehouse manager. The kid took off the tires from the wheels, spun them 180 degrees (IIRC) and rebalanced them with way less weight. These were the factory Michelin LTX tires so this issue can happen with name brand tires as well. There's a user in the 6.7 section who just had brand new Michelin Platinum tires mounted and balanced to which he still experiences this!

When I first drove the truck after my buddy installed the Milestar Patagonia AT/Rs in 275/65R20 flavor (stock size), there was no rear end hop at all or if it was present, it was virtually unnoticeable because we are talking about a 1 ton truck here and not a Cadillac like ride. Then once the tires wore down some, I am thinking, the rear end hop started up, but no where as bad as when I had the 18 inch steel wheels on with Treadwright 275/70R18s in winter kedge flavor. They are some heavy effing tires. The amount of weight it took my buddy to balance them was crazy. They performed well in winter, were very reasonable in price but due to the set of tires another friend of mine bought for his newer F150, same BF Goodrich K/O thread design mine were but he bought his in premium rubber (50k mile warranty) where my Winter Kedge (crushed walnut shells and glass in the rubber -- 30k miles), two of his tires developed a bubble in them where the thread started wearing off and caused a vibration as well. So I'll never buy them again. I will run these Milestars this winter but may buy a cheaper set of snow tires for the 18 inch wheels. The thread on those Milestars are pretty solid and do not expect a problem in snow. My manager buddy said that they sell like hotcakes, no one ever complains and they were only $650 out the door >> it helps to know people.

Here's a link to the longest thread on this subject in the 6.7 section.

https://www.ford-trucks.com/forums/1...40-45-mph.html

Here's a link to the Centramatic balancers I run on my truck. They do help with ride that I noticed when I first installed them. But they cannot overcome this rear end oscillation. But they have kept my front tires from going into DW (death wobble) as my track bar BJ is getting worn and my TB bushing is worn (worse than the BJ I believe... got under the truck with wheels still on the ground though I did jack up the front end some to make it easier to crawl under there -- and saw movement out of both with the bushing being worse than the Ball joint. I already bought a Apex Chassis TB BJ and will buy SPE's track bar bushing kit with bushing removal tool for it. My point is though that the Centramatics stifled the DW because it would want to start, then a split second later just stopped. All the components in my front end have been replaced. I am thinking those will be the last two. And the best thing is the Apex BJ has a grease fitting on it.

I want to replace those two parts before I put the beads in my tires. IMO it is the balance of the tires that directly affects how bad the oscillation is in these trucks. I will update here once I do with results.

https://www.ford-trucks.com/forums/1...balancers.html

 

Thank you for the detailed help! Ive seen several threads similar to mine about the hob however they are all for speeds around 45min. Mine is the worst about 70. I will be getting a new set of tires soon and thinking about going with 35s, I have an aftermarket set of 18in wheels that don’t have tpms sensors so I will follow your advice and see what happens!