Front Drivetrain Noise: Video !

Corey

Active member
Hey,

I need some ideas everyone. I've had the car into two different shops trying to figure out what this noise is - we can find anything definitive.

I'll try to describe it:

- It can only be heard while driving the car (weight on wheels).
- It appears to be coming from the front left.
- It sounds just like Zoidberg's whoop whoop whoop
- It's most audible in 1st, 2nd, 3rd (1st is loudest, then 2nd, then 3rd)
- The noise doesn't really start until ~2500 RPM in each gear. As rpm increases, the noise grows louder and increases in frequency until about 3000 RPM

- After 3000RPM, either the noise starts to quiet down, or the engine is now too loud and drowns it out, I can't really tell.

_ If I hold the car at the speed/RPM which produces the loudest noise (around 2600-2700RPM), I can change the volume of the noise by lightly and slightly pulsing the throttle by a couple mm or so.
- While doing so, the noise is louder while on power, and quiets down when I back off a tad (while trying to maintain that same speed/RPM).

- It seems louder when going up hill in that rpm range, and quieter while going downhill in that rpm range.


OKay, here is some background info.

205 Tranny. I've put nearly 50K km on it.

While in the shops, we checked wheel bearings by tilting/twisting wheels and with a stethoscope while on the lift with wheels spinning in the RPM range.

No evidence of worn bearings and we heard nothing with the stethoscope when placed on the knuckles.

The Front Left Inner CV boot has had a zap strap on it since before I owned the car. It's recently been replaced with a proper metal band and more grease added to the boot - no change to noise.


Now, I'd really like your thoughts on this finding:

With the stethoscope placed on the bottom of the tranny near the front left driveshaft, a very audible, constant groan can be heard.

When I listened to the noise, it didn't sound anything like the noise I was hearing while driving the car. Do normal gear sets make any noise at all?

Could this really be the source? Perhaps the noise changes and becomes audible while the wheels and tranny are loaded?

What is in the tranny near this location which could produce that noise?

Is it possible the inner front left CV is causing the noise? Keep in mind the boot had a zap strap on it and I have no record on whether it's been replaced, or if the boot had been torn and replaced....

Any help is greatly appreciated. This is starting to drive me nuts!
 
I swear I have had this on two of my alltracs (constant noise that starts at specific mph and then gets drowned out) and I believe its a wheel bearing. Problem is that I totally rebuilt my blue trac and not sure what the fix was. I did find that the bearing on the transfer case by the output shaft (connects to driveshaft) was really worn on my transmission. I also replaced the carrier bearings on the driveshaft. In my case whatever I did got rid of the noise.
 

Corey

Active member
Ya I'm about ready to start throwing money at it in a blind attempt to fix it.

I bought myself a stethoscope so this weekend I'm going to jack the car up and start listening for myself, see if i can find anything.

Thanks
 

lumbercis

Moderator
what kind of fluid are you running in your transmission? this is kind of a shot in the dark, but maybe you could change to a very different fluid than you are using, like OEM to synchromesh, or to a heavier or lighter viscosity rating, and see if the sound changes at all... thought it might be a cheapish way to see if it's some kind of gear whine from within the tranny.

Have your mechanics gone for a ride with you and heard the noise for themselves?
 

Corey

Active member
hey,

In the time I've owned the tranny I've run royalpurple syncromax 75w90, then redline Mt90, and recently redline 75w90ns.

I had hoped the same thing when I swapped in the 75w90ns, but no such luck.

Also, brand new tires installed.

And all the mechanics have heard the noise while driving with me. but we can't hear it when the car is in gear on the lift.

thanks again for the ideas everyone, keep em comin :)
 

Corey

Active member
Hey,

What do you guys make of this? I recorded this video today while the car was on jackstands.

The engine is held at 2100RPM in 2nd gear.

http://www.youtube.com/watch?v=Vp8IpBcL ... e=youtu.be

That can't be normal, can it?

I've got a second video i'll upload shortly

Edit: 2nd vid

Here is another video showing just the front left corner. The video starts with the car in gear at idle. I then proceed up to ~2500rpm in each gear, up to 3rd. Just before the end of the video I rev the engine up to 4000 in 3rd. (phone ran out of memory after that)

http://www.youtube.com/watch?v=QXzLvVS3 ... e=youtu.be
 

Landon

New member
dang dude... you can stop the wheel from spinning when its in gear? that looks to me like something is bad with the center diff... thats really weird, and most likely related to the noise for sure..
 

gearhead313

New member
Man, weird. Well in the vid, the wheel stopping is no big deal. the front diff is open and the center is viscous, so it is able to slip, but not much. when one wheel stops in the front, the other picks up its speed. No biggie.


Moving on, is the noise constant with road speed or rpm? does it change when on or off the throttle? change when braking? change when turning to the right or left from center? hot or cold ambient temp? engine temp?. That will be a start and we can go from there.
 

Corey

Active member
Hey,

I repeated the test today. However this time, the two fronts were spinning at the same rate - in the beginning.

Some owners had suggested that perhaps my calipers were sticking, causing the one wheel to stop with the open diff.

I confirmed that today. The front left caliper soon began to stick.


I also discovered something. I can hear the noise while the car is unloaded, BUT, only while in the car. It can't be heard from the outside while the engine is rev'd up.

So with the engine back at its 2100RPM, I used the stethoscope on the front left Caliper.

Ontop of the sorta metallic noise of brake pads scraping on the disk, I heard the noise!

I then tried pressing on the brake pad with my fingers to slow the disk down to a stop while listening with the stethoscope. And noticed the noise also slowed down and stopped - but was soon replaced by a sorta grindy noise as the rotor came to a stop which persisted until I released the pad.


So, I next thing I tried was to remove the left caliper and rotor and repeat the test (engine at 2100rpm, see if i could hear the noise inside the car) And I couldnt!

I couldn't hear the noise anymore with the caliper and rotor off of the front left corner. I also noticed that now the front right hub was completely stopped, while the front left was spinning up - so my front right caliper must be dragging a bit aswell.

In summary - I'm really hoping the issue is the result of the brakes, which would be awesome because I already have a Ksport BBK on the way from the UK.

Thanks Guys!

Moving on, is the noise constant with road speed or rpm? does it change when on or off the throttle? change when braking? change when turning to the right or left from center? hot or cold ambient temp? engine temp?. That will be a start and we can go from there.

Hey, glad to hear that is normal for the open diff. As for the rest, I quickly outlined it in my first post.

Cheers
 

Landon

New member
dang man, yeah brakes can be hella weird sometimes. i hope this fixes it. oh and if your ksport package gets delivered but you never see it, don't come looking for me. :roll:
 

Corey

Active member
Well, update:

New brakes haven't helped the noise sadly :(

I got back under the car and started wiggling the driveshafts about and found that I can slide them in and out of the transmission by no more than 5mm.

A bit more concerning however, is that when I push on the Side gear shaft/inner joint flange, the shaft can slightly move laterally inside the transmission, which translates to ~3mm of lateral play at the flange where I'm pushing.

In addition, with the left wheel off the ground, I can hold the inner flange stationary with one hand, but can rotate the shaft with the other hand - its barely visible, but I can feel it move.

Is that kind of play normal? Both sides do it, however the left appears a tad bit worse.
 

Corey

Active member
New find:

Found a parking lot this evening and just tried different running conditions - in gear, neutral, coasting, turning, etc

I discovered that while in neutral and coasting at idle, there is no noise - turning or otherwise.

However, if while in neutral and while coasting, I hold the engine rpm at ~2200-2500, the noise starts to appear.

This is the most interesting part though - the noise only really become noticeable when turning right. It doesn't happen nearly as frequently, if at all, when turning left or while rolling straight.

The noise is definitely in tune with rolling speed, and can be heard at any speed. Even at a snails pace while coasting and turning right.

But the sound is also RPM dependent - because it only becomes audible at that specific RPM range.

Any ideas!?
 

Corey

Active member
Tried the clutch while coasting - no change.

I'm booked into Audi tomorrow to see if they can figure it out . Toyota refuses to work on my car.

Hopefully it is a wheel bearing and not my tranny
 

tubasteve

New member
I had the exact same issue, the wheel bearing was alowing sagging when the car warmed up(driven 4 a while), an the brakes were hitting the rotor due to the rotor no longer being centered between the brake pads. I took out a thermal temp gun, noticed one wheel was 140~ and the other sitting about 220*. The hub was toast, the bearing....well toast and rotor and pads. I got major brake fade is how I noticed, this was on my first alltrac that had been sitting for 7 years.
 

tubasteve

New member
Corey Darling":18iwrnu6 said:
Tried the clutch while coasting - no change.

I'm booked into Audi tomorrow to see if they can figure it out . Toyota refuses to work on my car.

Hopefully it is a wheel bearing and not my tranny


Why do they not want to touch it?
 

gearhead313

New member
If it was a wheel bearing, then you'd be able to lift the car off the ground and feel play in the wheel as you wiggled it back and forth and up and down... have you verified that was all tight?


The only other thing im thinking is a motor mount is bad and letting the motor/trans touch somewhere making the vibe. Does anything clunk when you change gears up or down? When you reverse the car from a stop? Tough to internet diagnose something!
 
Top