2007CalSpec

Hey everyone...Watch the video and tell me if this is a bad u-joint.

http://www.youtube.com/watch?v=dWQqX...ature=youtu.be

Sometimes when I move from a stop I can hear a clicking noise but it goes away at cruising speed. It doesn't happen all the time. The noise starts at 1:14 in the video. I thought it was the rear axle or even the CV joint but wasn't sure.

3:20 in the video shows the u-joint and it seems to be louder here. I've also noticed a line of grease slung up around the transmission/driveshaft tunnel. You can pause the video at 3:23 and see the grease on the tunnel. There was also a little bit of grease on at least two bearing cup seals. I checked the u-joint for play and there was none. Zero. Zip. Before all of this noise, I started having quite a bit of vibration under the car. I readjusted the length of the CV joint from 3-5/8" to 3-1/2" and the vibration went away, well mostly. I still get a tiny bit only around 2100rpm in 3rd gear. The noise is also gone now. FWIW, the driveshaft is 11 months old. I'm still concerned that it IS the u-joint though.

petrock

Well, its got a beat and you can dance to it… :-)

Seriously though, I would remove the drive shaft and repeat your test to eliminate the drivers haft & rear diff from the equation. It is really hard to tell where the sound is coming from, but it is clearly two metal parts hitting each other. It sounds slower then the speed the drive shaft is spinning which is making me think it is not the drive shaft. Maybe something hitting the exhaust? If you grab the exhaust pipe with a well insulated glove while its making the metallic banging noise does the sound change? If so, then the problem is in the exhaust.

Good luck...

2007CalSpec

I took the car to a shop that works on high performance cars and they determined that the CV joint is going bad. They had it on a lift and raised the rear wheels off the runway and started the motor. They said the noise was coming from the CV joint and the sound was resonating throughout the hollow aluminum driveshaft. This driveshaft is supposed to handle 900HP but it looks like it can't even handle 500+HP. I had to drive it back home and leave it in the garage while I work things out with The Driveshaft Shop. They're going to send me a new driveshaft via cross shipment with a refundable $400 deposit that I'll get back when I send the old DS to them. The drive back home was scary though. Vibration and clanking got worse. FML.

2007CalSpec

Update: I received a new driveshaft from The Driveshaft Shop and installed it today. Took a week for them to ship it to me. The car is running good. No more noise. The old driveshaft had a bad CV joint. You can hear the clicking and play in it when moving it around. Let's see how long this new one lasts.