Hey team

 

Need some help.

1998 Legacy GT w/ 4EAT, 168,000 miles

2.5L

 

The car is running pretty well at the moment, a little rich (suspect a new O2 sensor).

 

My problem is that I have a wee bit of drivetrain vibration going on - usually from 1000 - 2500rpm, under acceleration and general driving.

 

Sitting in the driver's seat, it feels like the car is "wagging" it's tail. Once I reach 60mph it's totally gone (the revs are on 2600rpm).

 

What could it be?

Torque convertor? Shagged AT? Loose or worn engine & transmission mounts?

Bump because I know someone here has something to say!

 

On another forum, the driveshaft has been mentioned as a source of vibration.

And that Subaru driveshafts can't be re-balanced, so it's replacement.

 

?

first - how are your tires? a wheel weight could have fallen off, have them checked. look on the outside, if it's recent sometimes you can see where the wheel weight used to be. or rotate your tires and see if the vibration *moves* or changes. this would indicate a bad tire or wheel (severly dirty or damaged). wheels bolted down tight?

 

otherwise - driveshaft. the ujoints go bad. sometimes you can tell by looking at it if the ujoint is bad. otherwise pull it off (not hard to do at all) and it will be obvious which ujoint is bad. they feel lumpy and sometimes are even seized completey and not movable at all but yours doesnt sound this bad. they can degrade quickly, i wouldn't plan on waiting a terribly long time to fix this. doubtful it needs rebalanced, that is unlikely to be your problem. the ujoints are most likely to be your problem.

 

get a used driveshaft. cheapest solution.

 

on the older subaru's they can be rebuilt by a machine shop and they can install all new regreaseable u-joints. i got tired of replacing bad drive shafts with old driveshafts over and over again (but my XT6 is old) and finally got one rebuilt. st. augustine drive line shop (look them up on the internet) lists which ujoints fit your model (if there is one available for your car). or go to Rockford's website and see what they list for your application. rebuilding cost me about 190.00 for everything to have both halves of my driveshaft rebuilt with replaceable and greaseable ujoints. but if you just replace the bad ujoint you can probably get it done for 50-75 dollars. i'd recommend replacing them all if you plan on keeping the vehicle.

Thanks for the reply - but what is a "ujoint"?

 

I don't think it's the tires at all - the car hasn't been acting all squirrely, and it's only on acceleration - cornering, straightline cruising is fine.

 

Am I on the right track?

might be the infamous touque bind....do you have an Automatic??

 

I have a few posts on the topic if you do

might be the infamous touque bind....do you have an Automatic??

 

I have a few posts on the topic if you do

Yup, that's me!

1998 Legacy GT w/ 4EAT, 168,000 miles

2.5L

Any posts you can point me to? And thank you!

Ok, just read some posts about torque bind.

It does not feel like torque bind.

 

I have no issues with cornering, in fact last night I took an onramp at 50mph with no issues. Back end felt like it might have stepped, but that is probably due to winter tires and the Cusco swaybar set for oversteer.

 

Last night I was cruising home at 65mph. Popped it into N, and revved up. No problem - no shaking in the car like there was an exhaust part swaying under pressure.

 

So I believe it's something to do with the transmission + driveshaft. Which is a bugger.

 

I'm not confident I can diagnose this properly, so it'll be off to the local dealership.

Feel like I'm having a conversation with myself, but oh well, someone might get some use out of it...

 

I went and spoke to Mel Kistner @ Halpert Subaru in Mentor, OH. He test drove my car for a spirited run around the area, came back and put the car on the hoist.

 

Turns out my "wagging" car is because of a worn transmission mount, not the drivetrain etc. So that's a relief!

 

The only downside is that the car also needs a new exhaust system because of 2 holes in the catalytic converter sections.

 

All up, to fix the problems (vibration & rich running), Mel quotes me $1000 inc. labour.

Try driving the car in different gears and see if the problem happens at same engine rpm. If it is same engine rpm, it is not the drive shaft since driveshaft is now rotating at different rpm.

Try driving the car in different gears and see if the problem happens at same engine rpm. If it is same engine rpm, it is not the drive shaft since driveshaft is now rotating at different rpm.

My car does that. It has a deep vibration at 2.5-3k RPM. in 2nd and 3rd and kind of 4th. Whats wrong with it?

Try driving the car in different gears and see if the problem happens at same engine rpm. If it is same engine rpm, it is not the drive shaft since driveshaft is now rotating at different rpm.

It's not the driveshaft, it's the transmission mount (on my car).

Thanks though!

It's not the driveshaft, it's the transmission mount (on my car).

Thanks though!

 

I have a 95 Legacy LS with auto tranny and it has bad chugging or shuddering rather in low rpms, when you start out. Has nothing to do with cornering, so maybe this is the same as yours. I'm going to check the tranny mounts too.

 

Thanks for the post!