Help! WTF is this noise?

[xjdesertfox]

So, today I took the miata out since its been almost a week since I've driven it.

Along the drive, i noticed that I was having a knocking sound from the rear, to me it initially sounded like a blown shock. i continued to drive around, when suddenly the sound got WAY WORSE. The sound was very distinct, its a LOUD knocking sound. I believe the sound is coming from the center of the rear of the car. The sound occurs up decel but not at any time when I have a constant acceleration. This leads me to believe that the U joint/s are bad. Or I have a bad CV?

In the morning Ill be able to jack the car up and take a look, but Ive never experienced a car that made this sound. The sound is a mix between a flat tire, and the sound of a piece of heavy rubber taped to the drive shaft knocking around as it spins.

Ive I drive VERY slowly, I can almost hear something dragging? or something rubber sounding like its tearing?

If it is the Ujoint, I need to source a new driveshaft right? Since the joints are non serviceable? How do I go about checking the CV axles?

[psulja]

Is it happening when you're not braking and just coasting or only if you're braking gently?

[xjdesertfox]

I actually just figured it out this morning. It was happening when I would coast. Turns out the bolts that hold the shaft to the pinion had worked their way loose. Blue loctite + torque wrench = winning.

[I<3flippyheadlights]

Well that was easy

[psulja]

I actually just figured it out this morning. It was happening when I would coast. Turns out the bolts that hold the shaft to the pinion had worked their way loose. Blue loctite + torque wrench = winning.

Lol ya, after I responded I went into your build thread and saw you found the problem. Glad you got it fixed quickly!