Drivetrain noise at highway speeds?

Greetings! 99 LGT Wagon 5MT here. As stated, I got a nasty noise, most noticeable around 60 - 70 MPH, from the tranny/drivetrain when accelerating, but it goes away when coasting, so it's not constant. Really, the best way I can describe it is it's the same kinda noise you get when driving on a dirt/gravel road; grumbly and gritty, like a wheel bearing noise, but not. The pitch stop mount I put in doesn't exactly help either, lol.

 

For what it's worth I noticed my front axles have a decent amount of play in them, they jiggle up and down and can also twist a little bit by hand. That and the condition of my clutch is also unknown and questionable, it's definitely seen better days. Dunno if those things might be related, but figured it was worth mentioning.

 

Any thoughts? Thanks!

Half shafts may be a good place to start. Look through the transmission FAQs at the top of this forum.

 

Flush the trans fluid and the rear diff also so you know both those are serviced and maybe don't rule out wheel bearings completely. My friend had a forester that had that same gravely /growling under accel and it turned out being all 4.

 

Im sure another ear can chime in and recommend other things to consider. But be sure to search, chances are, something like this has been covered somewhere in here.

I'm getting the same noises...its a little less since I did my atf fluid a couple times...I'm going to be changing the front and rear diff fluid this weekend hope fully it will quiet down after that....and if it doesn't then carrier bearing and bushings and outriggers under the rear differential, there is a lot of rubber and keepers under neath these cars and if your like me and have over 250k on the body you might start thinking about replacing all that...just good practice and peace of mind that everything is new.

my passenger side front axle has had a torn boot for a long time and the axle is now going bad and I get a feeling of driving over gravel on the highway, but not really any sound. just ordered a new axle and will be replacing soon.

Just a suggestion.

 

Check your psi on each wheel. If they are too low or too different from the other, the transmission will whine (auto). Our tires need to be at 32psiF/30psiR at all times. If the psi is off, the transmission will bind as if it is in 4WD, which you do not want.

Don't mean to divert that question with one of my own...I believe my transmission is binding a little bit and I won't have the money for a new diff for some time, i don't want to ruin my transmission so I was thinking about putting it in fwd for a while....Can anybody tell me if I should just park it or ill it be fine for 20 mile round trips to work?

I just hope it isn't too late for that..I have done the fluid changes but since my power steering is out for now I can feel it sick style...I just replaced the motor 2 months ago and just hoping my tranny isn't next on the block. It grabs well into gear but all the way through second gear it just feels like its shuddering especially decelerating.

Half shafts may be a good place to start. Look through the transmission FAQs at the top of this forum.

 

Flush the trans fluid and the rear diff also so you know both those are serviced and maybe don't rule out wheel bearings completely. My friend had a forester that had that same gravely /growling under accel and it turned out being all 4.

 

Im sure another ear can chime in and recommend other things to consider. But be sure to search, chances are, something like this has been covered somewhere in here.

 

 

I've done the fluids AND a wheel bearing within the last 6 months :/. Though now that I think of it, it did seem to get a little better after doing the bearing. Those inner CV joints are definitely sketchy to me though. I got state inspection coming up so I'll have em all checked out.

Just a suggestion.

 

Check your psi on each wheel. If they are too low or too different from the other, the transmission will whine (auto). Our tires need to be at 32psiF/30psiR at all times. If the psi is off, the transmission will bind as if it is in 4WD, which you do not want.

 

 

 

I'm pretty scrupulous about the tire pressures but I usually keep the rears at 32, is it really that sensitive? I also have a 5-speed. On that note, I've heard a dragging clutch will cause that same kinda binding/AWD constantly on?

Don't mean to divert that question with one of my own...I believe my transmission is binding a little bit and I won't have the money for a new diff for some time, i don't want to ruin my transmission so I was thinking about putting it in fwd for a while....Can anybody tell me if I should just park it or ill it be fine for 20 mile round trips to work?

 

 

 

Think I read in the manual that driving wit FWD isn't a good idea and is only for towing? I might be wrong...

When you say the inner cv' s have some play are you talking about the joint of the cv or the cv cup that goes into the trans? The cup that goes into the trams will have play, up,down,side to side and a very small amount of in and out play as well. This is NORMAL, my 99 LGT does it, my 96 L did it and my friend and his son's 98 and 97 LGT all do it. When a wheel bearing goes bad you will hear a growling noise that will change pitch when driving and swerving left to right a bit. Since you stated the noise is only apparent when your on the gas and goes away under decel then it's something thats under a load. Like your rear differential pinion bearing or side bearings or all three. It could also be the clutch. I would get the car on a lift and while it's running and in drive allowing the wheels to spin get a mechanics stethoscope and try to pinpoint the noise. Remember find where the noise is the loudest because noises will transfer through a lot of stuff. So a noise could be heard like a foot away from where it's originates from. GL.

The cup I guess, the green parts. The also have a bit of twisting play. and I was told ages ago the my front diff. had play in it and I'm assuming that's what they meant. Thanks for your advice!

Is a noisy drive train automatically cause for worry? I've been noticing that my car is somewhat noisy at average speeds on city streets. I was told by Firestone that my front left wheel bearing needs replaced so I'm assuming what I'm hearing is that, but I was just curious because on the old truck I used to drive the transmission was pretty loud but it worked perfectly and never gave me trouble.

Wheel bearings are quite common on Subarus and to check them you can jack up the car and check for play by moving the tire by hand left to right and up and down. Also while your driving turn the steering wheel left and right if you hear the noise change pitch then its def one of the wheel bearings. I'd say drive around 40 or higher to hear the noise better. GL.