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Discussion Starter #1
So when I bought my truck the guy told me he had a new rear-end put under it due to the old one makin a lot of clunking noises. I noticed in the dash it has the G80 RPO code. How can I check and see if the rear-end that's under it now is also a G80? and what would cause the speedometer to be off by about 6-7mph? This is on a '97 ECSB 4wd. 5.7L 4L60E. 265/75/R16 and by the RPO codes it supposedly has 3.42 gears.
 

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Discussion Starter #2
So, once I pull the cover off and confirm that it is 3.42s in the rear, what else should I look into on the speedometer being wrong?
 

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Are you sure the clunking isnt your U joint?
 

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Discussion Starter #6
I didn't find out about the new rear-end until about 2 weeks ago. I had a friend of mine who just got a new Z71 to run beside me at 50mph and my speedometer read 57mph. So that's when I went to talk to the guy. About 2 months ago I had to pull a buddy of mine out of the mud and used 4 hi and had no problems? What would be a sign that the gears are wrong? I didn't notice anything out of the ordinary....:think:
 

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the difference between 3.42s in the front end and 3.73s in the rear end is negligible off-road...just make sure not to run it in 4hi on the street. I had 3.73s up front and 4.56's out back in my 98 and you couldnt even tell off-road there was a difference.
 

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Discussion Starter #8
oh ok, well I'm fixin to be runnin a set of 305/70R17's on the truck and I want some gears so I was thinkin 4.10s???
 

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I would avoid ANY 4x4 usage if the ratios are wrong. Offroad if you happen to hit traction for a second with all 4 tires can you say parts breakage.
 

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oh ok, well I'm fixin to be runnin a set of 305/70R17's on the truck and I want some gears so I was thinkin 4.10s???
Think you'll ever lift the truck and go with bigger then 305's? If so do NOT waiste a dime on 4.10's IMHO. Get 4.56s now.
 
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