Getting sick of this "shimmy" at 65+

Motostroker · Aug 1, 2014

2013 F250 CCSB

My truck has a horrible shimmy! I have ruled out rims and tires from a buddies truck. It still does it with his also.

My truck feels like it's about to fall apart it's so bad. The driveshaft was balanced, along with removing wheels and bolting rotors back up. Truck in drive on jack stands. Etc. still no obvious movement I can measure. Pinion, U-Joints, etc, are all great.

I'm thinking warped axle shaft? Harmonics from tires beginning to bounce? I realize these 6.7s have only 3 leaf springs. Which leads it to need zero effort to bounce truck.

Get this though, the vibration goes away when I load the hottest tune, and floor it around 80. Leads me to think the pinion angle is changing from the axle wrap.

What's the correct pinion angle on these trucks?

I do have 5 inch (5* tapered) blocks. But my truck had a shimmy before that also. I'm about to find a dyno and see if the owner can let me use it to find the issue.

Shoot me ideas to try please.

Powerstroke Man 6.4 · Aug 1, 2014

Motostroker said:
2013 F250 CCSB

My truck has a horrible shimmy! I have ruled out rims and tires from a buddies truck. It still does it with his also.

My truck feels like it's about to fall apart it's so bad. The driveshaft was balanced, along with removing wheels and bolting rotors back up. Truck in drive on jack stands. Etc. still no obvious movement I can measure. Pinion, U-Joints, etc, are all great.

I'm thinking warped axle shaft? Harmonics from tires beginning to bounce? I realize these 6.7s have only 3 leaf springs. Which leads it to need zero effort to bounce truck.

Get this though, the vibration goes away when I load the hottest tune, and floor it around 80. Leads me to think the pinion angle is changing from the axle wrap.

What's the correct pinion angle on these trucks?

I do have 5 inch (5* tapered) blocks. But my truck had a shimmy before that also. I'm about to find a dyno and see if the owner can let me use it to find the issue.

Shoot me ideas to try please.

I remember ford sent out a letter in '08 for the 2008 DRW's because of this "shimmy". Ford's fix slow down LOL (i'm not joking). Till this day my 08 dually still has this and I cant figure out why. The truck had this "shimmy" ever since it left the dealer lot with 10 miles on it. I'm getting tired of it. Its so bad to where steering wheel will shake your hands off.

Motostroker · Aug 1, 2014

Same here, mounting go pros everywhere underneath the truck tomorrow. I'm begging to think engineering flaw.

Weak springs, that wrap to much, that leads to u joint binding at higher speeds.

Does anyone with traction bars have this issue? I would buy OUO's bolt on style with adjustable top plate. I just don't know if it will cure it or not

Powerstroke Man 6.4 · Aug 1, 2014

Motostroker said:
Same here, mounting go pros everywhere underneath the truck tomorrow. I'm begging to think engineering flaw.

Weak springs, that wrap to much, that leads to u joint binding at higher speeds.

Does anyone with traction bars have this issue? I would buy OUO's bolt on style with adjustable top plate. I just don't know if it will cure it or not

Ford knew about this problem since 08 or earlier and still haven't fixed it.

Motostroker · Aug 1, 2014

I have never rode in a 6.4 with this issue. Only a 6.7. come to think about it, 90% of the 6.7s I rode in shimmy

Powerstroke Man 6.4 · Aug 1, 2014

Motostroker said:
I have never rode in a 6.4 with this issue. Only a 6.7. come to think about it, 90% of the 6.7s I rode in shimmy

Come to think of it my 6.7 does it also add that to the list LOL.

Motostroker · Aug 1, 2014

I'll be bored tomorrow, I'm measuring everything and throwing it in solidworks or auto. Then I will manipulate it to pinpoint stress areas. I'll post back.

dsberman94 · Aug 1, 2014

lincolnlocker found something on his 6.7 that sounds like it would cause your issue. im not sure which thread its in though. try PMing him to find out.

Motostroker · Aug 1, 2014

dsberman94 said:
lincolnlocker found something on his 6.7 that sounds like it would cause your issue. im not sure which thread its in though. try PMing him to find out.

I read his thread, his rotors wobbled horribly. Yet mine stay true? It's worth a shot though. I'll shoot a PM shortly

sootie · Aug 1, 2014

Jared commented that with ouo bars and some good shocks in the rear, it went away...

TripleE44 · Aug 1, 2014

Mine does this **** too. With traction bars and carli commuter fox shocks. The weirdest part about mine, is that it happens at 65+ now, but only on certain roads and not just rough roads either.

It also kind of moves around at what speed it does it. In the past it has been at lower speeds.

Another weird thing is sometimes its worse than others, and I drive the same exact route to work monday-friday. Today it was just a slight shake, but yesterday I could see my passenger seat shaking.

lincolnlocker · Aug 1, 2014

Motostroker said:
I read his thread, his rotors wobbled horribly. Yet mine stay true? It's worth a shot though. I'll shoot a PM shortly

did you venture off on any of the threads posted from other sites? there are a few guys that have the exact issue you have.. im certain my chit is bent but the guys that have that same hope I have goes away. mine turns into a vibration. its actually getting worse.

live life full throttle

Motostroker · Aug 1, 2014

I had surgery yesterday so I won't be able to do anything for like 2 weeks. I'm not too concerned as I have the 450 I just bought to drive. So I'll tear mine all the way down, and inspect

MINK · Aug 1, 2014

Motostroker said:
I had surgery yesterday so I won't be able to do anything for like 2 weeks. I'm not too concerned as I have the 450 I just bought to drive. So I'll tear mine all the way down, and inspect

let us know what you find...my 08 and now my 10 does it but not near as bad as what you guys make it sound.

Motostroker · Aug 1, 2014

MINK said:
let us know what you find...my 08 and now my 10 does it but not near as bad as what you guys make it sound.

Will do buddy

01pwrstkr · Aug 1, 2014

MINK said:
let us know what you find...my 08 and now my 10 does it but not near as bad as what you guys make it sound.

I just posted in your other thread. I'm looking at a 08 ccsb. At what speed does it normally do this on the 6.4's? And is it when accelerating, slowing, or just cruising? I want to see if the one I'm looking at does it and how bad before I buy. Thanks!

Motostroker · Aug 1, 2014

01pwrstkr said:
I just posted in your other thread. I'm looking at a 08 ccsb. At what speed does it normally do this on the 6.4's? And is it when accelerating, slowing, or just cruising? I want to see if the one I'm looking at does it and how bad before I buy. Thanks!

I have never had the shimmy in a 6.4 before. And I have owned three of them. Some have though.

MINK · Aug 1, 2014

01pwrstkr said:
I just posted in your other thread. I'm looking at a 08 ccsb. At what speed does it normally do this on the 6.4's? And is it when accelerating, slowing, or just cruising? I want to see if the one I'm looking at does it and how bad before I buy. Thanks!

60-65 cruising.