kyoo

iTrader: (29)

Can you guys help identify this noise?

- Car making a tapping/knocking noise only at 25mph
- Doesn't matter if I am accelerating or decelerating
- Doesn't matter if I am in gear, which gear I am in, or coasting in neutral
- Disappeared after taking some logs (ran the car hard) (Update, noise is just randomly present now)
- Comes back when the car is cold

http://s166.photobucket.com/albums/u...rent=Noise.mp4

Right at 2-3 seconds there - only around 25mph

Update: New trans and transfer case (street strip and stage 2 t-case) from Shep.. Noise is still there, but a little quieter and a little more on and off... any other ideas?

clc3667

iTrader: (1)

Hopefully an Evo expert chimes in on this as well but my 2 cents. If it went away with out fixing it on purpose then it's probably going to come back. I doubt a motor knock would get better so I imagine it's vibration related idk?

kyoo

iTrader: (29)

Thanks - yea it sounded just like something non engine related but it's just weird that it was speed dependent rather than like RPM dependent or something, and then disappeared after I flogged the car. I've never heard of something like that before.

kyoo

iTrader: (29)

you're right, drove the car again and it was making the noise, only at the start when it was cold though...... mysterious

kyoo

iTrader: (29)

bump

migs647

iTrader: (19)

/subscribed

Definitely non-engine. When was the last time you changed your t.case fluid?

Have you checked your driveline for any play? I can imagine going at low speeds doesn't put much pressure on the driveline.

Last but not least, it's your mechanical diff

kyoo

iTrader: (29)

ahaha - today is Monday, all drivetrain fluids and engine oil were changed on Tuesday, 6 days ago. haven't checked driveline for play, not sure how to do that. I had timing work done on Tuesday as well as the installation of a wideband O2 sensor - however, the noise started BEFORE any of this work was done. So the work done neither fixed the problem nor created it.

I was thinking though, that the violent banging of my rear diff at low speed turns could have forced something loose in the drivetrain, though I have no idea what that would be, nor why it would go away when the car has been ran hard. Diff doesnt make a peep anymore of the drivetrain fluid change but the noise is apparently still there.

Sam

kyoo

iTrader: (29)

bumperoo - still there when cold, disappears after i drive it around for a while.

Berts24

iTrader: (3)

driveshaft bearing maybe?

kyoo

iTrader: (29)

is this a symptom of the driveshaft bearing going? how can i check for sure?

crazybaldhead

Maybe, maaaybe, it's the exhaust shield. On the passenger side of the car the exhaust shield is close to the body, just behind the tranny. If your car was up on ramps or something, it could be really close to the body. There's a rubber stop there to prevent rattling, but it doesn't always work. Just bend down, a push the shield away from the body with a stick. Mine made that noise after my dog kept crawling under the car to sleep and pushing on the shield when he crawled out.

kyoo

iTrader: (29)

thanks i will def check that out - hopefully it is something like that. was it a relatively loud sound in the cabin?

crazybaldhead

It made a sort of rattle when the car just started. Then as the car warmed up, it would go away. I'm not saying that's your problem, just offering a suggestion.

kyoo

iTrader: (29)

ah gotcha. this only happens at 22-25mph so it's probably something else. something that doesnt require clutch or gear engagement

kyoo

iTrader: (29)

bump