shaking at 50mph

[whyme]

about a week ago i was on my way home from work and the back end of the truck started hoping around on me, every time i let off the gas and slowed down a bit it went away, i would accelerate and hold speed and after a min or two it would come back. i chalked it up to road surface as Ive had that happen on some roads and parked it.

got the winch back on the truck and went for a ride today. now i get a hard shimmy at 42-45, it goes away and then at 50 it starts bouncing hard (feels like the back) and at 52 the wheel starts to jerk and truck feels like its getting unstable (obviously i backed down at this point).

the winch has been off for about three weeks and prior i had a few vibration problems but nothing like this. anything i encountered was light and went away once the road surface changed or you could accelerate through it. up until now I figured tires but this is outta the blue. quick look over reviled nothing obvious.

just curious if anyone has similar experience, ill check for loose nuts and bolts along the drive line, i thought maybe bearing?? the fronts where solid last i checked but ill check again for play.

 

[steelandcanvas]

Kinda simple, but did you check your tire pressure? What do your front shocks look like? Start simple and go from there.

 

[whyme]

Kinda simple, but did you check your tire pressure? What do your front shocks look like? Start simple and go from there.

I'll give em another look everything was good a few days ago and I haven't been looseing pressure.

Brings up another question. I've been running 50psi all around for highway use as stenciled on the truck. I know a few peole have played with this, any recommendations? No loads to speak of and it's a winch truck if that matters.

 

[steelandcanvas]

I run 50 PSI all around, I think the tires wear better, nicer ride (if there's any such thing in a Deuce). Another thing would be to look at your tie-rod ends for excessive wear.

 

[jollyroger]

Don't listen to Steel and Canvas.......Both his deuces are currently broken.

Seriously though SnC knows his stuff.

Usually when I get the death wobble it has to do with alignment. Shocks can be a culprit too.

Tie rods, drag links and king pins.

Tie rods and drag links are easy to check. Just do a shake and wobble test. If they are loose or wobbly you can adjust them. If that does not work they need replaced.

Kingpins require jacking the truck up and wiggling the tires and wheels top and bottom. Even then you might not be able to get enough leverage to make them get loose.

Alignment is something best decribed from the TM's but the death wobble can be from excessive toe in or out. Usually toe out.

That pretty much summs it up unless your tires are square.

 

[Gravel]

I get the same thing from the rear when I run "off road" pressure on the highway.

 

[ranchhopper]

Check the dogbones they act as the torque arms for the rear if they are bad they allow the rear axles to go out of line and that causes the rear to jump as the axles move forward or back and side to side from the looseness.

 

[whyme]

Check the dogbones they act as the torque arms for the rear if they are bad they allow the rear axles to go out of line and that causes the rear to jump as the axles move forward or back and side to side from the looseness.

whats the best way to check them aside from removing and inspecting each? just pry bar and watch for play?

also, the weight of the winch on the front def exacerbated the problem. the wheel does shake but not until the truck is bouncing bad. if it was front end (wheels, bearings, tie-rods, ect) wouldn't i feel it in the wheel before the truck?

im trying to compare this to light trucks so please forgive my ignorance.

 

[rlwm211]

I run 50 in the front and 35 in the back. I also carry an S280 shelter all the time. Even with the load, I have checked tire wear and found that at 50, the rears were wearing centers off faster than the shoulders of the tires. I gradually lowered the pressure until I hit 35 and found the truck rides great and tires seem to be wearing evenly. The fronts were at 45 but I checked and found that they were a tiny bit underinflated. Back to 50 and all is well.

You have to remember that 50 psi is for a max load of 10000 payload. I am hauling around 4000 and have more windresistance than weight. I have put almost 5000 miles on my deuce in the last 20 months and have had no issues running my tires at less than 50 psi.

As far as your vibration, I would start with lugs, then dog bones, then driveline and make sure all the bolts between the flanges of the drive shafts are tight. I would jack up each axle and see if you have a tire that has a broken ply. That would cause an out of round that would get worse at speed. You should be able to see an out of round tire by simply spinning the tire and use an indicator to watch for a variation when you spin it.

To me, hopping is a byproduct of an out of round condition. It could be drive line, or tires, or a huge chunk of rock or mud on the inside of a dual. Chances are this will be fairly easy to find once you start the diagnostic process. It is a process of elimination so start somewhere and work your way through.

Hope this helps

RL

 

[ranchhopper]

I pick the rear of my trucks up with a big loader at work to check them I guess any way to get the axle up in the air so you can try to move it back and forth would work.

 

[combat32]

I shake at all speeds, even standing still.What does that mean?

 

[Jimma]

Mine started hopping real bad at about 46mph. when I picked it up from GL. It was a slow, long ride home. I checked the tire pressure and they were all under 20 psi. I aired up to 50 psi and it went away. Next step to help the ride is the front shocks.

 

[Heavysteven]

I would guess a combination of things. I would starting working from the back to the front of the truck.

1. Bearings set properly, check
2. Any lose bolts on the drive shafts? Check trans to transfer?
3. Next the front. You should just go ahead and do the step by step to replace the boots and seals. In the process you'll go through all the front end bearings, kingpins, steering....etc
4. Shocks
If the problem is not found after that I'm clueless.

 

[davidkroberts]

does turning at speed have any effect. If it is an alignment issue or possible bearing the change in load may change things enough to give you an idea where things are coming from. Im sorry but ive never had anything happen that was similar, what i posted above is what i would check in any other vehicle.

 

[asgtoolman]

I shake at all speeds, even standing still.What does that mean?

Parkinson's????

 

[stumps]

First check when anything weird happens to the ride should be the lug nuts. Next is tire pressure.

-Chuck

 

[EMD567]

Check the tires for tread separation. My chevy 2500 was going down the road just fine, and then all of a sudden, the back end started a jumpin. Got out and looked, and I had a 4" bubble in the right rear.

 

[steelandcanvas]

I shake at all speeds, even standing still.What does that mean?

You need another drink.

 

[whyme]

well today i got around to checking pressure all around, went to the gas station (no compressor at my apt yet) and after spending $3 to check and top off just the fronts and one tandem i made a run to autozone to get the parts to make my own glad hand air line ($30 in all).

they where all a little off, the fronts at about 40 and the others between 30-46 with the exception of one that is as of now dead flat. i topped the rest to 50 and it helped but now i need to deal with the flat, it's the left rear inner. i didnt discover it until i tried to check the pressure and couldn't find the valve, its gone. i have to get a square 15/16 socket to get it off. local truck stop wanted $80 to fix it, $40 just to pull it off.

harbor freight have them?


on a side not i dont think this is the sole cause of my problem but im kinda stuck till i get it fixed.

 

[jwaller]

I run 70 in my front tires 50 in the rest. more pressure makes for easier steering.