Hey guys, this is my first post on this forum, but i am in desperate need of help. I have a 1993 2wd 4-runner, and recently a huge shaking/vibration problem has occured. Basically, when im driving, or accelerating, everything just starts to violently shake. It does this most when under acceleration, past 1.5/2k rpm. Even though at this point everything (steering wheel/whole car) vibrates a ton, the shifter will vibrate/shake the most. It used to be that when i let off the gas, it would stop and roll smoothly, but lately its continued to vibrate even when off the gas. The higher up the rpms go, the more it vibrates/shakes. All this leads me to believe its drivetrain related, rather than something with the wheels/suspension being out of balance.

So...basically once under acceleration, everything shakes violently. I have no clue what to look for. Can you guys please help me out? Up untill this point it has driven wonderfully, and it was about to be put up for sale acutally, and now i dont want to do so untill the problem is solved. Any help will be much appreciated, thank you.

-Dylan

 

The first thing I can suggest would be to get your motor mounts checked. Happened to a friend of mine in a *cough* saturn.

 

A blown joint/bearings in one or both ends of the drive shaft might also cause it to wobble. Did the vibration start suddenly or gradually worsen??

 

Hmm good point. Try stopping, leave it in gear with the breaks on hard, lightly accelerate. Does it still shake to all hell? What about if you accelerate in Park or Neutral?

 

U-JOINTS.

I kill mine at least once a year. Easy and cheap fix. take a look at them I'm almost willing to bet money on this one.

Like I said easy to replace all you need to do is remove the drive shaft. and use a BFH and a Vise to whack out the u-joint. they are under $50 bucks at the part store

 

Wow, thank you all very much for the quick responses.

I checked out the motor mounts, and they seem to be ok.

hillbilly- The problem gradually worsened.

gapguy- i will try that right now.


One question for all- If i were to look at the u-joints, how can i visually tell if they are bad.

Again, thank you all, i really appreciate the help.

-Dylan

 

You may/may not be able to visually determine if the U-joints are shot. Depends on the severity of the problem.

Park the rig on a flat surface and set the E-brake. Slide under and grab the drive shaft near the joints firmly with both hands. Try moving it in all directions. If you're able to feel/produce any slop in either U-joint, its likely causing the vibration. Also look for any signs of excessive grease or metal fragments around the caps of the U-joints.

Doing as gapguy suggested should help narrow it down a bit for you.

 

welp, i looked at the u-joints and sure enough one part (the part that holds the joint), was split in like 3-4 places. This was on the tranny side of the driveshaft.


gapguy- It does shake when i accel on the brakes.



4Hummer- So what do i need to buy to replace this? And once i take it out i will just whack out the joint and replace it?

Thanks!

 

Put the truck in Park, and try and turn the drive shaft side to side. there should be no slop at all.


got this image from here here. http://mgaguru.com/mgtech/propshaft/ps102.htm

Notice on the top of the above pick, the wear between the drive shaft and the output ring. This is from the drive shaft hitting. If your U-Joint is as bad as it sounds this will be very noticable. (Like someone took a grinder to it)