bonus12

Thanks for reading! Is there anything in the transmission that can make a loud tap noise that is NOT rpm-dependent? Gear doesn't matter, but the car must be moving in gear with the clutch out.

I have a speed-dependent noise that sounds like a hammer on a nail. The sound is coming from under the car, roughly under the back seats. It doesn't always happen, but it's much more common during city driving (stop and go). Strangely, I can "caress" the sound away with the gas pedal quite easily.

I'm thinking the exhaust is banging a heat shield screw while the differential is spinning because this has happened before, and it's coming from roughly the same origin. But I'm not sure it's the same noise, and today it happened while I was only going 5mph. The cat was replaced not long ago, and maybe the exhaust pipe is too close the the body.

Sorry for the long post. All help is greatly appreciated and I hope the news isn't bad! Please let me know if you'd like more information. Thanks!

John_AZ

??? CV joint bolts coming loose ???
J_AZ

william_b_noble

I had a tooth on the pinion gear fall off - it sounded like that for a little while before all hell broke loose.

mytrplseven

Drive shaft coupling bolt coming loose? Look in the inspection hole behind the big rubber cover on front end of transaxle.

Jamesr6967

Could be a bearing as well, wheel bearing or torque tube.

bonus12

I'll research your ideas for a bit. Thanks guys.

Is there any more information I can give to help the diagnosis?

bonus12

To quote a rennlister (V2rocket_aka944), "torque tube noise sounds like a coffee grinder when you let off the gas in lower gears and decelerate. trans makes a mix of whirring noises normally."

My car makes a loud ticking noise, can it still be TT or pinion gear? My noise comes from way under the rear seats in the center of the car, so wheel bearing can't be it, right? Driveshaft coupling bolt sounds suspect, but the ticking/hammering makes an extremely regular beat, based on speed. Am I just in denial?

Again, the noise is sometimes absent, like on the highway.

Just trying to narrow the problem down. This is outside of my experience.
Thanks!

bonus12

I just drove 7 miles with absolutely none of the noise.
Does this rule out anything? I drove in all gears and at high speed.

bonus12

bump for a couple more opinions?

mytrplseven

Perhaps a bolt that was coming loose finally fell out. I'd inspect the CV's and the drive shaft coupler for missing hardware.

bonus12

Thank you, I will check, but this noise has been intermittent since it began. It will probably come back, and go away again. I'll have to just check these bolts. I was hoping the intermittency would help me rule out some things.

dave1192

I'd vote for an inner CV joint. I had one that would apparently settle into a good drive position and run quiet occasionally, until it failed completely, turned into a crank, and left me by the side of the road. Easy to find then!

bonus12

I think I found the source of the noise, with your help! Cv joint. i went under the car and found that the driver side axle pivots back and forth, which seems normal. BUT, it bangs into the outer cv joint and makes the noise. no missing or loose bolts. it seems like the cv is ok, it's just the axle banging into its housing or something?

this cant be normal? anyway, after pivoting the axle with my hand, the noise is gone. it seems like sometimes the axle finds a comfortable spot banging against the outer cv, and stays there until it goes back. this is like what Dave suggested above. it explains the intermittentcy.

is a seal missing maybe? records show that both driver side CV Joints were replaced about 25k miles ago by a good mechanic. any thoughts? is it a bad idea to drive like this as long as it doesn't make ugly noises?

Thanks a lot!!!

flashx

IT wont hurt a thing till it locks up. Think its good to have a nice pair of sneakers cause you be walkin after that

austin944

My car's been making an intermittent speed-dependent noise sort of like yours, except it's coming from the right rear. It's loudest and occurs most frequently after starting from a standing stop, while previously having come off the highway in gear. If I modulate the throttle or put it in neutral, the sound goes away. I never hear it on the highway. I'm assuming it's the CV joint and will probably get to it this weekend.