I had a friend in the car after we went Christmas shopping, and he says, "show me what this car can do." We were at a stop light, so when it turned green I got on it. Took 1st gear up to about 6000, then just when I was shifting into 2nd, there was a really loud "BANG!" sound. 2nd gear pulled just fine afterwards. I had a huge box ( a gift) that was wedged between the headrests, and thought that it might have been that box getting thrown around, but really it was too loud for that. Did the car backfire?

I got out and checked underneath the car...all was fine. I tried it again later that day and it pulled fine through all gears and hasn't done anything weird at all since. I DEFinitely did not imagine this loud noise! What was it? It was right between 1st and 2nd gears.

LOL, maybe I broke the sound barrier!!! YES!

 

Is your transmission still in the car? Cuz it sounds like it fell out. LOL

 

God, that was the first thing I thought. Talk about a scary moment. But, like I said, it runs as good as ever, even under heavy gas. I mean, it's only got 18,000 miles on it, with no mods whatsoever.
If it WERE the tranny, I would surely know that something was wrong by now...right?

 

Ummm.. if your tranny was "out" or fudged, we wouldnt be having this conversation..



Sully

 

Whew. That's what I thought, too. My car runs perfectly. I'll probably never know what the noise was, but it scared the turd outta me. All I could think was, "My Z! My Z! My Z!"

 

I would do a visiual inspection from the Mani throughout the length of the exhaust. And make sure your didnt blow a seal or somehow a hole.

Sully

 

I'll do that, but wouldn't there be a noticable change in the exhaust sound?

 

I was riding with a friend once when we slid on ice. Until this day he swears that he heard the sound of broken glass as he thought that we're colliding with the barrier but he saved it and there wasn't even a scratch on the car. Go figure.... .

 

Do you have any mods? I have seen a 350Z with testpipes and exhaust backfire before.

 

This might sound strange but bare with me...
Did you happen to have a empty bottle of soda with the cap tightened in your car? Cuz the same thing happened to me. It was last winter and I was driving to work and all of a sudden, this loud bang came out of no where. I was so shaken up I quickly pulled over and check under the hood and around the car, nothing. The car didn't stutter and nothing seems to be wrong as I drive the rest of the way to work. Later that night on my way back, the same thing happened. Turns out there was an empty bottle of soda in the passenger foot area and as it gets cold, the bottle implodes and shrinks up. As I drive it and have the heater on the windshild and foot, the bottle quickly expands and makes a very loud pop sound. Just to make sure it was causing it, I left the empty bottle outside and then brought it inside, sure enough it did it.

 

Did you feel anything abnormal in the shifter when this happened?? The reason I ask is that the 6MT in the Z is a notchy pile of junk (Im on the 2nd one myself) and I wouldnt doubt if it was your tranny/synchros making that sound.

 

Nope, didn't feel a thing out of the ordinary at all.

No bottle of soda pop, either. Good story there!

Welp, it hasn't done anything weird at all since that one time, so maybe it wasn't the car. Suuuuure was loud though.........(sigh).