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Vibration question: 1999 Ram 1500 4x2 automatic

1655 Views 4 Replies 3 Participants Last post by  BlackSheep01
Odd vibration originating somewhere outside the cabin when the truck is under load (e.g. climbing an overpass or merging into faster traffic).
Truck has a 318 with 103,000 miles and has recently been repaired from a light front-end collision; it sat for an extended period while the
owner saved up money to fix the A/C condenser and the radiator core support and the front bumper and the hood latch. This has been done.

The transmission has been checked out by two shops and is operating normally. The front-end alignment has not been checked.
There is not the noise typical of bad u-joints with this vibration. Tires are worn.
Brakes are functional and safety/parking brake engages / releases normally.
No codes set.

The vibration seems to come from in front of the truck if you're riding in the front seat, but from behind you if you're in the back seat.
I'm thinking wheel bearings, but it might be tires out of balance / worn.

Does that sound remotely close to y'all?
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· Super Moderator
1966 Crown Coupe, 2016 200 S AWD, 1962 Lark Daytona V8.
17,313 Posts
Bearings usually growl. Tires can shake and shimmy that changes with speed.
Are tire pressures OK? Any scalloping or 'bumps' felt in the tire carcass. Try a rotate to see if it changes the sensation? Is there another vehicle with the same size wheels that you could swap over for a road test?
Is this felt more in the floor, seat or steering wheel? Can you look down and watch you knee shake while driving?
U-joints can get worse under load and the shudder can feel like it's coming from everywhere. They spin ~4 times faster the than tires.
Chock the wheels, pull the driveshaft and articulate the front and rear joints up/down and left/right to feel for any binding in the needle bearings.
Finding the cause will be a process of elimination.

· Registered
209 Posts
Discussion Starter · #3 ·
Yay .... I don't have jackstands or ramps to lift this puppy on. Fortunately the owner already has a set of better tires on identical rims, and wants to swap them over.
There's not a 'growling' type of sound.
FWIW on personal experience I had a 1986 pickup front driver wheel bearing nearly fail -- the only clue was an excessive amount of what I thought to be brake dust.
Yep, this truck's a project.

· Registered
748 Posts
I put new(er) tires on my RAV4 and no longer think it has 2 bad wheelbrarings.

On another point, could the frame be bent or "sprung" from the collision?

Finally check all the hangers and mounts designed to isolate vibration.

· Registered
209 Posts
Discussion Starter · #5 ·
We've had 3 different pros ok the frame as not sprung or bent. The core support and condenser were toast, though.
I think I might suspect a motor mount if the wheel swap doesn't stop this. Thanks for the hint!
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