Need4Camaro

Just what the topic says... I have an 2002 Pontiac Firebird and under light to mid throttle I'm getting a vibrating / metal rattling sound coming from the back of the car. I also have had an SES on for a long time for a Vacuum Leak in the gas tank and the rear axel has been removed atleast twice in attempt to fix it but to no avail. Whats causing this rattling sound? possibly a loose fuel pump? is my rear axel going out?? what could this be?

meangreenchevy

I had a similar problem in my 97 ss I thought it was the driveshaft rubbing the exhaust boy was I wrong later that BOOM! Blown rear... I guess for you a good place to start is put the car up on jack stands, leave it in neutral, get under there and spin the tires by hand see if here anything to try and locate it also when turning the rear wheel by hand try to feel if the wheel dosent turn freely or if it feels like its skipping teeth inside the rear like it will grab the let go than grab again just my 2 cents

Injuneer

What's the exact code for what you describe as a vacuum leak in the fuel tank?

Need4Camaro

I'll try that but god I pray its not my rear end... if it is then this will change everything about my car project and I might wind up having to trade it in on something newer...

P0446 and P0452 ...

TBSPW

definetely sounds like youve blown a few teeth of the ring and pinion...mine lasted only a few days until it completely exlpoded and im now on my 4th rear.

Need4Camaro

Darn... I really don't understand how this is possible with just a V6 with 3.42's and I've never even performed a burnout in it... This is just perfect... just what I need, a blown rear... I was ganna do a motor swap but that is ganna add $2k to the cost and Im not sure if I can foot that... I might have to look into a newer car...

btw was there any warning before it exploded or will you be having a nice drive at 65 MPH and then suddenly BOOM? Was it at highway speeds? Will the axles disengage and shoot out the housing and send your wheels with it? Does it get progressively louder before it happens?...

johnny6

Before you jump to any conclusions raise the car and remove the rear differential cover. if you start seeing metal shavings, gear teeth etc. then you know what the problem is. It only takes a few minutes to remove the cover, it probably needs a fluid change anyway. What grade fuel are you running? I'm asking this because i had a similar problem when i first purchased my car, turns out the rattle metal sound i was hearing from the back was detonation, switched to premium fuel and never heard it again.

Injuneer

P0446 = Evap. Emission Control System – Vent Control Malfunction

P0452 = Evap. Fuel Tank Pressure Sensor Circuit Low Voltage

Would appear to be related to the EVAP canister, and the vacuum being pulled by the engine. Have they examined and/or replaced the canister? Have they examined/replaced the tank pressure sensor?

Would appear totally unrelated to the noise in the rearend.

Need4Camaro

I did some tests today. I took it out the garage and left it in reverse and kept my foot on the brake. It continued to rattle for a good minute or two... Then I put it in Neutral and kept my foot on the brake and revved to 2k RPMS, it rattled but it wasn't as strong as it was in Reverse... then I revved to 4k RPMS... and it got loud... Then I applied the parking brake and looked under the car just to make sure the drive shaft wasn't turning and even in idle it was still rattling and the drive shaft wasn't turning at all.

I wouldnt know honestly. I know the fuel pump was bad when I got the car and the replaced it no charge... then I got the P0406 code and had to bring it back to have it serviced and it was a bad / leaking fuel line... they replaced that no charge, and now this...

I replaced the canister in the engine bay but it didnt solve the problem and left me minus $40...

cody96ss

F-Bodies are rattle cans anyways. I have been chasing them down since I bought my first one and haven't found 'em all. As far as the rearend goes, if you have to replace it, don't replace it with a 7 1/2'', 7 5/8''. I have put 3 of those damn things in and just found a guy in Indiana who does 9'' rears for $1250 installed. 9'' setups are cheaper than you'd expect, so look into those first...

Injuneer

Of course 9-inch rears weigh more, have higher mechanical drivetrain losses, offset the pinion shaft to one side and drop the pinion shaft 3/4", causing torque arm and clearance issues in the 4th Gen, making the pinion angle more critical to control. Then there's the non-existant limited slip diff's for high axle spline count, etc. etc.

mzgp5x

I had similar noise and I found it to be a destroyed cat converter brick. Noise in low and mid throttle, but quiet under WOT due to high exhaust flow. I also broke my 7 1/2", but it did not sound like a (rattle). I broke a tooth off my pinion and the magnet picked it up so it did not lock. B.