Strong vibration at 1500-3000 rpm
 

yes, yet another vibration post.
today my 98 3.4 has developed a very strong vibration when it hits 1500-3000 rpm on the speed up to ~60 mph. The steering wheel shakes like it's a jeep =)
it's not a wheel balance issue as it does not happen at any speed in N or if the car is just rolling and RPM is around 1200. If I rev the engine in N I don't get any vibrations. no engine codes.

what's your best guess? what should I look at?



Update: u-joint replacement did the trick

I’m not 100% on this answer but I would give your Ujoints a check to rule them out. I had my ujoint pretty much disintegrate and the vibration was pretty bad though I felt nothing in the steering which is why I’m hesitant to say ujoint


Sent from my iPhone using Tapatalk

Wait does this only happen when rolling out can you recreate it in park/neutral? If you can it's definitely something engine related, I would guess motor mounts if you aren't throwing a code for a misfire. Have you looked to see if there are any pending codes that are just waiting to trigger your CEL?

To confirm, when you are going 60 mph and shift to neutral the vibration goes away?
When the vibration is occurring the steering wheel shakes left and right?

I'll take a look at ujoints, but I have my doubts - vibration seems to be coming from the front and it's strong on the steering wheel. couls be a CV, but in RD they don't get any torque so only speed should matter, not RPMs

That is the first thing I would check, too. I had this problem 10-12 years ago, and found the vibration very unsettling. I though my engine was about to grenade. If it happens only when driving, and not when just revving the engine, then the problem is likely not an internal engine one. Could be engine mounts, though.

To determine if it is the u-joints, crawl under your rig, grab the driveshaft at every u-joint, and try to wiggle it side/side and up/down. If you feel or hear any looseness, then that is likely the problem.

Trouble is, the problem is either expensive or a PITA to fix. I had to surgically cut and press out my OEM u-joints, then install new ones. The new u-joints that I used are both removable and serviceable (with Zerk fittings). If I keep them greased, they will never wear out. If I don't, and they do wear out, then they will be relatively easy to replace again, since they are designed to be removeable. Back then, the u-joints were about $50, and the small bench press I bought was about $50. That $100 total, and a few hours, beat the living snot out of $1,500 for a new OEM driveshaft. (This is all from memory, and I don't recall which brand of u-joints that I bought.

correct it goes away if I turn to N or just let go of the gas.

the steering wheel shakes like it's a bad case of unbalanced wheels. in all directions.

no codes, and I can't replicate the issue in N. engine works fine from idle to 5k rpm

It could still very likely be the u-joints. You probably won't feel or hear a problem with them if the driveshaft is not under load (like when letting off the throttle or just revving in neutral).

Strange for sure. Are you in 2wd or 4wd when this happens? Is it a rhythmic vibration or random?

I've tried both 2wd and 4wd - no difference. Will lift the truck today to check ujoints and suspension.

Definitely another vote for u-joints if the vibration is only when you're on the gas.

This might sound a little crazy, but it will eliminate or confirm if the rear driveshaft u joints are the culprit. Chock the wheels, put it in 4HI (4HI locked if that applies to you), remove the rear driveshaft, then go test drive it and see if the vibration is gone. With the transfer case in 4HI (or 4HI locked if that applies to you) and the rear driveshaft removed you will essentially be in front wheel drive. It won't hurt the vehicle at all, but remember to keep it in 4WD until you reinstall the rear driveshaft again. If you put it in 2WD with the rear driveshaft removed there will be zero power transfer from the transmission/transfer case to the rear axle and even park will not work.

If you do this and the vibration goes away then that points to either rear driveshaft joints (most likely) or a rear diff pinion bearing (less likely).

Check for play in upper ball joints.

U-joint on shaft likely culprit
 

I had the same problem with the same symptoms.
Turns out the u-joint was almost disintegrated in two shaft ends.

Did the job in a weekend day. There is this Youtube guy replacing them on a 2WDR 4 runner. This is what I did

how to replace toyota 4runner or Tacoma u-joint with simple tool - YouTube

I didn't have a air hammer, nor a bearing press...so I did it with a hammer.

Also I got a U-Joint with a grease nipple, so that my grandson doesn't have to repeat the repair. :-)