Rocking felt in front 1/3 of vehicle, out of balance tire or?

[LiqTenEXp]

hey,

I've noticed that the truck gets into a bad oscillation around 30-40 mph and the whole front of the cab feels like it is being tossed around. Feels like an out of balance tire but I don't feel anything in the wheel like you would in a car.

I am familiar with hopping from the rear axles and know how to identify/stop it by adding power or using the brakes. This is not in my mind associated with that. It feels different and that rear axle thing is more of a front/back or up/down oscillation. It don't believe I have flat spots either. The tires have under 1k miles on them (11R20) and I have warmed them up on an almost hour long trip and it still happens. TP is 90 front 70 rear.

I couldn't find any wheel weights on mine and figured that might be an issue...Are they placed inside the rim out of sight? Looking around I see mentions of "beads" but I still have tubed radials in this and not sure how that would work since I can't remove the valve stem I would think.

Truck info: 1985 M923

 

[Artisan]

Ummm, does not sound good, could be a simple fix but be sure to nail it down
before usage. Perhaps jack up one wheel in front at a time and see if the wheel
always spins to the same place, suggesting a heavy spot on or IN the tire or rim.

Look inside the rims for chucks of debris.

Jack up and check wheel bearings.

Look at driveshafts for missing balancing weights check u joints for validity.

If I remember right the TM has a troubleshoot for this ...


Keep us posted what you find.

 

[LiqTenEXp]

Driveshafts/u joints look fine, I went through and greased the truck and inspected them as I greased them.

They front tires do have some rocks stuck in them so I plan knockin them out and spinning the front wheels. Size of them are up to or around an inch so maybe that's all it is. I'd laugh if that's it. You have me thinkin now. There are plenty of rocks in them and I have heard a couple shoot out at speed... I know what I'm doing tomorrow morning.

 

[davo727]

I had the same thing with my 14r20s on the front the other day coming back from fort hood. Like theres a body stuffed in each of the front tires.

 

[WILDBOY6X6]

I would check the steering play tie rod ends and rest but the gear box is a common thing to cause that on these trucks and 809's too.

The tires will too if they are cupping on edge's of tread also bad shocks can cause this too.

 

[LiqTenEXp]

I don't feel any play in the wheel but I will inspect the tie rod ends.

Tires are not cupping. Truck was through Depot 3-11. Would they have replaced the shocks out of normal routine, what kind of inspection can be done on the shocks?

Thanks!

 

[SoylentGreen]

I hope you find out what the problem is, mine does the exact same thing. New shocks didn't help. I also jacked up each wheel and they spun freely with no play in the bearings and no wobble.

 

[LiqTenEXp]

Removing these appears to have helped after taking a short ride today:



about 3/4 of what came out of the 10 tires, started saving them to show you guys once I realized how much there was