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New to Firebirds...rear end noise.


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#1 Alexjordan22

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  • Year: 2002
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  • Model: Firebird
  • Engine: 3.8 V6
  • Transmission: Automatic

Posted A week ago

Hey all, just joined and excited to have my very first F-Body. It's a 2002 Firebird V6 Automatic. It's got 97K miles it's been a CA car all it's life and it very clean. Some slight fading of the dash pad, something rattling underneath when I go over bumps, and what sounds like bearing noise from (I think) the rear. I understand these rear ends don't hold up very well behind the V8 cars when they're thrashed, but what are the odds that an automatic V6 car has an issue with the diff?

I'm thinking (hoping) it is either low on fluid or needs axle bearings. But I just bought it an hour ago so I'll know more when it cools down and I can get underneath it. I plan to pull the diff cover to inspect as well as put new fluid in. Any advice helps!

It may also need headlight motors, as the PO told me that when it rains they seem to go slower or something. Not sure, they seem to work ok right now. Thanks.

#2 Injuneer

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Posted A week ago

Welcome ! ! !

 

Does the car have the optional limited slip differential (G80 code on the Service Parts label)?  If so, when you replace the lube, you need to add 4 ounces of the GM Limited Slip additive.

 

The 7.625” 10-bolt is adequate for a stock V6 w/ auto trans.


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381ci all-forged stroker (Callies Stealth, Oliver billet rods, BME 2618-T61 nitrous pistons) - 10.8:1 - CNC LT4 heads/intake - Comp Cams solid roller - MoTeC M48 Pro engine management - 8 LS1 coils - 58mm TB - 74#/HR injectors - 300-shot dry nitrous - TH400 - Gear Vendors 0.78:1 O/D - Strange 12-bolt - 4.11 Pro-Street gears - AS&M headers - true duals - Corbeau seat - AutoMeter gauges - roll bar - Spohn suspension - QA1 shocks - a few other odds 'n ends. 800HP / 800lb-ft at the flywheel, on a 300-shot. 11.5 @ 117 MPH straight motor
 
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#3 Alexjordan22

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  • Engine: 3.8 V6
  • Transmission: Automatic

Posted A week ago

I'm not sure, but I'll check the door tomorrow to see. Thanks for providing the rear end code to look for. I have a hard time believing the rear end in this needs rebuilt, but who knows. I'll get to do more digging this week, or I may just take it to a shop and have them diagnose it for me.

#4 Injuneer

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Posted A week ago

Have you checked the fluid level yet?  It isn’t unusual for the pinion seal to leak.  That may show up as a band of oil spray transversely across the underbody.  And age can take a toll on the carrier bearings or axle bearings, even if the mileage is low.

 

Not sure what the Owner's Manual shows for the 2002, but the maintenance schedule for my 1994 shows that changing the rear axle lubricant is required only if the vehicle is used for towing.  The limited slip rear requires a single lubricant change after the first 7,500 miles.

 

My carrier bearings got noisy near the end of the 36,000 mile warranty, and were replaced by a dealer.  But in all honesty, beside being a V8 with the 6-speed manual, and I was spraying a 125 HP shot of nitrous.  I replaced the stock 10-bolt with a GM 12-bolt, with heavy duty Eaton limited slip at about 60,000 miles.  No problems after that.

 



#5 Alexjordan22

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  • Engine: 3.8 V6
  • Transmission: Automatic

Posted A week ago

I have not checked the fluid level yet, but I have time tomorrow to look at it so I'm hoping I can find something obvious that could be causing it.
Also, no G80 code on the service parts sticker.

#6 Alexjordan22

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  • Engine: 3.8 V6
  • Transmission: Automatic

Posted A week ago

It ended up needing a new Axle shaft and axle bearing, although I did replace all the rear end bearings. Most of them had some imperfections and we're a little loose, it's much better now.




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