I have 2006 F-350 suspension, axles, and steering under my Excursion. It has always ridden smooth on the highway until a couple weeks ago. I barely avoided a car wreck, skidding about 15' sideways down the highway. Shortly thereafter I noticed a horrible all vehicle shake that felt like riding a jack hammer. No exaggeration.

Had my tires rebalanced 3 times within 4 days and the tires seemed to be bad so i just replaced them with brand new ones today. Much to my dismay, this did not alleviate the vibration. The vibration is random, sometimes rides smooth. Usually happens between 60-75 mph but can be felt slightly at slower speeds.

Jacked up the rear axle off the ground and let it run at those speeds with the old tires. could see the axle hopping up and down a little and feel the vibration in the vehicle. It is not in the steering wheel, it is in the seat of the pants and the whole truck makes noise from the rattling. Feels like it is most likely in the rear end.

I'm going to look more closely at the rear shocks which are only about 1 year old Rancho RS9000s, the old style. Have new big ones in front. Kind of thinking a shock may be sticking or leaking. The vibration is very fast, like a shimmy.

The limited slip does not grab nearly as well as it used to. Could the clutches have worn and warped or have debris floating around in there? Leaning less toward the idea of wheel bearings. Driveshaft feels tight and did not bounce when the rear was jacked up, but it could be something I can't see.

Any other ideas? Anyone had this happen with similar running gear?
Thanks,
Matt

 

It isn't the shocks. The shocks could not cause the rear axle to vibrate when the axle is off the ground.

I'm thinking your slide may have bent your rear axle housing.

 

You could take the shocks off and it wouldn't do that..Did you remove the tires and get it up on stands and run it up to see if it still shakes? You can check for a slightly bent axle with a long straight edge. Just put it on the hub flat and measure to the bed somewhere. Turn the axle and measure all around the hub. If its slightly off it will show up with a 3 foot straight edge. You could have a bent driveshaft or bad ujoint also.


Dick

 

If it were still under warranty, I'd simply take it to the dealer. YOu don't have to say what happened.....

 

it could be a bent wheel,but should have found it while balancing tires

 

try a known good set of tires?

shift to Netural while coasting... disconnects tranny from driveshaft


Kenny

 

i didnt know that a little slide would bend the rear axlehousing on a ford ,, im selling my 350 tomorrow,,raph nwas right ,,these things are unsafe at anyspeed.

 

i didnt know that a little slide would bend the rear axlehousing on a ford ,, im selling my 350 tomorrow,,ralph n was right ,,these things are unsafe at anyspeed.

 

I wouldn't think it would bend the housing,which with floating hubs wouldn't cause a viberation

 

Sounds like you flat spotted the tires. Heavy trucks and tire don’t work well when going sideways, there’s not much you can do to fix it but replace them. If you don’t fix it soon your could blow your shocks out. Need to get to a good tire shop and let them look them over.

 

again i stil with borrowing a known good set of tires... some shops swear tires balance out, but they really dont...

also

What are you talking about? Who said the guys axle was bent? Honestly - if it is the rear, the only way to bend the axle is to have too much driving force, because sideways force puts stress on the rear hub, if I am remembering the design correctly..

why is your 350 unsafe at any speed? I have had mine over 100mph with no issues stock and then i did it with 37's... i don't do that any more cause its hard to stop all the weight, but i did it - so ill admit it.

Anyway - i still say try a friends tires... try ford truck world, in your area, those guys help ALOT

kenny

 

I've had this setup with the previous tires around 114 mph a handful of times and it was always smooth. This sudden problem is still occurring but only at random. I've driven the same sections of road at the same and different speeds a few times now and cannot cause the vibration to repeat. I've tried coasting in neutral while it was doing it and the vibration continued.

I am becoming increasingly suspect of a bent rim, or the simulated bead locks on my wheels. I too doubt the housing is bent, though the actual axle shaft itself may be slightly tweaked, possibly binding threads.

Since my limited slip is in such bad shape, i am also suspect of problems from the clutches wearing out. Something like debris making its way into the wheel bearings. I'm now running a brand new set of Dick Cepek Fun Country II 37x13.5x17 tires on my same beat up wheels. Perhaps my beat up simulated bead locks are causing the problem. I need to have these things road force balanced on a Hunter GSP9700. That will determine whether or not the vibration is in the rolling stock.

 

or throw a set of stock sized wheels and tires, or somebody elses wheels and tires that run fine on their truck and save the GPS70000 or whatever money - thats a great balancing machine, but the people who own it are not afraid to charge big when people use it for diagnostic.

I still say get some new tires (i mean wheels with those tires) and throw them on your truck.... somebody in your area must have stock wheels, thorw them 20 bux to use them, they will be overjoyed


(edit) All my vibration issues with my wheels and tires was always random, depended on the heat of the day, the weather - it was so random that I could not account any one thing... that was on my trxus mt's - now i have BFG AT's on the same wheels and all is well, slight vibration, but i have to check and re-do my u joints and re-grease the axle shafts cause that may be another problem i have (a clunk noise)

good luck bud


kenny

 

have a 450 dulley put 6 tires had bad vibration. spent 200 on tires balance -match nonthing helped took truck to drive-line place they said booth drive shafts bent. no idea why, getting new shafts. sure thought it was the tires. good luck.

 

7.3Ex, did you ever resolve this problem?