I’ve long been a fan of cartalk, but never posted, so I’m hoping the collective brainpower here may help! When I bought my tundra used a year ago, it has always had a vibration that affected the whole car (not steering-wheel specific), and was worst at 60-65mph, but a hint was there even at lower speeds. It was annoying, but bearable, for example if you look at the passenger seat at these speeds, you can see it wiggle back and forth about 1/2". It seemed highway speeds were where it hit a resonant frequency.
In the past month, things have gotten much worse and when the truck has been sitting for a few days, if I quickly leave the house and hop on the freeway (only about 1/2 mile away, I get a vicious vibration mostly in the steering wheel and less so in the rest of the cab. The wheel wiggles about an inch and a half back and forth at highway speeds and letting off the gas, braking, accelerating doesn’t make much of difference, just speeds up or slows down the vibration frequency.
The wild thing is that it gets much better after about 2-3 miles. No longer really shaking, just a mild vibration like it has always had. If the truck is warm and I hop back on the freeway a few hours later, no vibration, just when leaving the house in the morning.
So far I’ve:
had tires balanced and rotated @ America’s Tire
crawled under to inspect the driveshaft and u-joints, no clear damage
towed a heavy trailer to see if it would make it worse (no difference)
I’m hesitant to take it into the dealer without some clear culprits in mind. I feel they often have the tendency to just throw new parts everywhere without doing much diagnostic work. I hope you all might have some ideas that could lead me in the right direction! Thanks!
Binding U-joints are one possibility since you said the whole vehicle shakes, not just the steering wheel. But a visual inspection like you did will not necessarily see anything. A mechanic should be able to put it up on a lift and run it in gear to see if anything is binding.
Likely either U-joints, rear differential, or tires/suspension.
U joints: Did you grab hold of the driveshaft on each side of the u-joints and twist it, see if there is any play at all in the u-joints? If not, that’s the first thing to try. There should be absolutely not play in any of the u-joints. Are there zerk fittings to allow you to lube the u-joints? If so, try that. You’ll probably need a needle fitting for your grease gun to gain access to the fitting.
Rear differential: Inspect the rear differential fluid level. Twist the whole driveshaft and see how much play there is in the rear differential. There is usually some, but not much. Edit: A rear differential about to go out will cause a vibration similar to this. But it usually never gets better, only worse, and very quickly much worse.
Tires/suspension: Since you’ve already has the tires balanced and rotated, and that did no good, unless you can spot something wrong with the suspension by pushing and pulling on the various parts and looking for unusual play, you’ll probably have to take it to an alignment shop and see if they can spot something wrong. There is some possibility you just have a bad tire, and rotating it just put it on a different wheel. You’d have to rotate some new tires in to disprove that, which seems pretty expensive way to do a diagnosis, but maybe that is what you’ll end up having to do.
Anyway, there’s some ideas to discuss w/your mechanic.
Thanks for the comments, the steering wheel started vibrating excessively about 800 miles after the rotation, so I don’t think it was directly related, although I suppose a tire could have gone bad in that time and that is the cause of the new, worse vibration. Based on all of your suggestions, I think I definitely have some things I can try as a shadetree mechanic. I think I might try to rotate the spare tire in place of each tire one at a time and see if it improves the vibes. I also haven’t had it up on a jack to really wiggle the driveshaft at the u-joints, so they could be bad but I didn’t feel it because there was tension on the shaft. I’ll have to double-check, but I don’t think these u-joints have zerks, the 4WD version does I know, but I don’t think mine does. Thanks for your ideas, I’ll let you know how I get on!
Another idea is a tire could be out of round. You might could rig up something that just almost touches the tread on the tire (with the car jacked up on that side), then spin the tire and watch the clearance. The clearance should remain the same – or very close to the same – for the entire 360 degrees. I don’t know what the max out of round spec for tires is. Maybe somebody here knows. I expect you could probably start to feel a little something wrong if a tire was 1-2 mm out of round. 5 mm out of round, you’d definitely feel a vibration I expect.