Diagnosing CV Joint, Wheel Bearing or Front Differential issue on 2001 Forester (MT)

[Steff]

Hello All - 

 

My first post to the forum. I am trying to diagnose a growling noise that I get when accelerating, most prominent in 3-5 gears, over 35 mph. I have read a lot of posts on the web but am sort of confused by conflicting write-ups. 

 

Symptoms:

When I am accelerating at higher speeds, I get a growling sound in addition to the engine rpms going up. This a deep sounding grrrrr, coming from the front end. If I let my foot off the accelerator, the sounds stops. If I tap the accelerator the sounds will occur again, with every push there is a corresponding grrr... Sound does not seem to change if I am turning in either direction. 

 

Some things I have read say that this may be a wheel bearing issue, but then why would it go away when not accelerating. Wouldn't the wheel bearing make noise if the wheel is simply turning? I have also read and saw some youtube vids where they say this would be a high pitched whir sound.  Mine is very much a low pitched grrrr sound.

 

I also thought perhaps it might be the cv joint and front passenger axle. Here, I should say my front passenger axle boot is torn and there is some play in the front passenger axle. maybe 2-3 mms of pull on it at the wheel. Not near the diff.

 

Lastly I have read that perhaps my issue is the front differential, which I am hoping it isn't as that seems to be the most expensive. Is there some way to determine what the front differential issues sound like?

 

 

Any thoughts or advice are highly appreciated.

I am mainly stumped one the type of noise sound and when it happens. It is most definitely most pronounce the faster I go. Rarely heard lower then 30mph. Only heard on acceleration. Turning in either direction seems to make no difference.

 

I am planning on replacing the passenger front axle to cure the torn boot issue and movement. I guess that is the best place to start, but if that doesn't seem to sounds like  why this noise would occur. please let me know...

 

 

cheers,

Steff

 

 

 

 

 

 

Edited March 22, 2016 by Steff

[forester2002s]

Is the noise the same in different gears?

For instance, you are in 4th gear and hearing the noise.

What happens if you change to 3rd gear?

Or vice-versa.

 

Another way of phrasing this question is to ask: Is the noise related to engine-speed, or road-speed?

[subnz]

I would suspect  CV joints  as you say CV boot torn.   usually diffs whine continuously when bearings gone there.

 

As suggested previously it could be your gear box too

Edited March 22, 2016 by subnz

[1 Lucky Texan]

CV joints definitely go bad regularly enough - but so do wheel bearings.

 

any work done in the last few weeks?

 

is the sound central or left or right?

 

checked the trans fluid level?

 

use an infrared thermometer and compare hub temps L to R after a highway run. If one side is consistently hotter - maybe a bearing?

[Rooster2]

a bad wheel bearing makes an grrrrrrrrrrrrrrrrrr sound when stressed as in accelerating, or on a turn like exiting a freeway ramp, when the roadway wraps around. I would tend to think it is a bad wheel bearing rather than a bad half shaft. The grrrrrrr sound is not a high pitch sound, more of a medium pitch sound.

[CNY_Dave]

My bad front pinion-

 

 

the key to telling is a wheel bearing increases 1x the rate you speed up, the pinion 4x the rate (spins 4.11 or 4.44 times faster than the wheels)

[idosubaru]

Trans or front diff, or inner cv joint

 

Inner joints usually have some vi brations or noises while accelerating up a hill with Steering turned to full lock. Turn left and right at a stop sign up an incline with steering turned all the way and punch the gas pedal - any noises?

 

What is the transmission oil looking like? Has it ever been changed?

MANUAL transmission so

 

What happens as you push the gas pedal up a steep grade- where throttle and load increases but it's not actually accelerating? Nothing or noise or vibration.

 

Front diff a usually whines like said

Input shaft and main bearing issues - some of the better MT guys can comment on those but fluid condition is one question.

Edited March 22, 2016 by grossgary

[Steff]

Thanks for all the responses. 

 

As far as I can tell, the noise is not related to engine speed or road speed. It is a consistent growl when accelerator is pushed. Same growl in each gear, faster tach not equal to louder growl. 

 

I do notice in the morning when I start the car, that the steering feels a bit off. But i think that is due to the fact that I need a belt up front. Once it warms up, the steering issue and some squealing goes away.

 

I am going to pull the wheel, try to pull the axle to fix the cv joint, as it needs it anyways, there is play in the axle. The I will check the hub and see if the wheel bearing is making noise during spinning. 

I will also check the trans fluid level. I need to figure out where that is.  

 

Then I will report back on where I am at... 

 

cheers,

Steff

[1 Lucky Texan]

trans stick is on the right side near the firewall, down kinda low.

 

when the steering feels odd - or there is some squealing from the pump - look inside the PS fluid tank for foam/bubbles.