My dad's '97 Outback has a shake that develops between 20-30mph under acceleration. It then goes away and returns really heavy between 50-60mph. At that speed I can shift into neutral and it will go away.

 

I have checked play in both front axle shafts, they are similar and do not seem out of the ordinary. I believe the culprit is the center support bearing for the driveshaft. I had similar symptoms on one of my other cars.

 

I climbed under last night and pushed on the driveshaft near the bearing. There is play there but how much is mormal?

sounds like what a driveshaft would do. the ujoints are even more common than the carrier bearing to fail. really hard to verify on the car. sometimes there's slop in the ujoints and you can tell by yanking, pulling, and shoving. but other times the joints are "seized" or so tight that it doesn't exhibit play on the vehicle, but is notably hosed when you take it off. so there's really no way to "verify" with 100% accuracy that the driveshaft is good without removing it. i don't know how often that happens, if it's rare or not, but i've seen it.

 

every one i've seen gets worse over time, starts out lighter and eventually the drivers rear view mirror isn't usable it's bouncing so much.

 

has this one gotten worse?

The bearing itself can go bad and will create a whirring/humming noise when driving similar to a bad wheel bearing.

The rubber isolator around the bearing can deteriorate and cause the driveshaft to move around. I'm not sure if the bearing can be replaced or not. This is not a common issue though, so a used driveshaft out of a junkyard should fix it. A new shaft is like $6-800 IIRC.

Since he got the car with just over 100k it has had the 20-30 mph shimmie but very light. That has gotten worse as the 50-60 shimmie came on. The 50-60 shimmie is so bad it will cause the car to shake side to side.

 

Car now has 150k. I didn't see anywhere that has the center carrier bearing available. Wondering what would be more cost effective: take a chance on a junkyard driveshaft OR drop the current one and install new carrier and bearing and new u joints.

if you're not positive of the cause i'd lean toward junk yards. even if you are, used isn't a terrible option considering how easy they are to replace and expensive new stuff is.

 

i would consider the hundreds of dollars for new bearings and ujoints unless you were certain it's the driveshaft.

 

if it started out as noise and now vibrates it could be a wheel bearing.

 

if it started as vibration and has noise too now, then it's probably driveshaft.

 

i guess you don't know how it started though. wheel bearing should be obvious, it's usually notable front/back or left/right.

First suggestion I have, is to tighten all road wheel lug nuts. Just tonight, I had to tighten mine on 99 OBW, because the front wheels were just a tad loose. Tightening the lugs eliminated the slight shimmy I was getting at about 60 mph.

 

If that doesn't help, then have all four road wheels balanced. When road wheels are getting balanced, it is a good time to check for worn suspension problems like ball joints and tie rod ends.

 

I hope you get it straightened out. Keep us posted on your progress.

When my driveshaft was going out it made a terrible clunk clunk clunk that got louder with speed. never went away except in reverse when it was being loaded the other way.

If it's just the rubber isolator that is too flexxy that could be fixed with a bit of the right kind of goo...

 

 

Dave

If it's just the rubber isolator that is too flexxy that could be fixed with a bit of the right kind of goo...

 

 

Dave

 

Do tell. It will not hurt to try it.

I've heard of people "fixing" worn/bad bushings with 3M Window Weld. Not sure how well it works out in the end but that stuff is pretty tough.

I've heard of people "fixing" worn/bad bushings with 3M Window Weld. Not sure how well it works out in the end but that stuff is pretty tough.

 

Yeah, that sounds like the urethane goo someone used. I think they used it on the bushings for the rear differential.

 

Dave