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73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Rear Drivelines, Drive Axles and Gearing => Topic started by: Plasticfan on February 20, 2017, 03:41:11 PM

Title: Rear axle gear change
Post by: Plasticfan on February 20, 2017, 03:41:11 PM

Want to swap out my 2.73 gears for 3.42.  Will the 3.42 fit in my 2.73 housing?  Are all the pinions 30 spline?

TIA, Don

Title: Re: Rear axle gear change
Post by: Captkaos on February 20, 2017, 09:01:11 PM

what year and size is your axle?  12bolt or 10bolt.
All 10 bolts have a 30 spline pinion.
It is the carrier that you want more spline count.  Only the later model 1989-1991 10 bolts got 30 spline axle.
Carrier break on a 10 bolt is 2.56 / 2.73

12bolt truck axles all have 30 spline.
Carrier break is 2.73 / 2.76 / 3.42 / 3.73

Title: Re: Rear axle gear change
Post by: Plasticfan on February 20, 2017, 09:12:11 PM

Quote from: Captkaos on February 20, 2017, 09:01:11 PM

what year and size is your axle?  12bolt or 10bolt.
All 10 bolts have a 30 spline pinion.
It is the carrier that you want more spline count.  Only the later model 1989-1991 10 bolts got 30 spline axle.
Carrier break on a 10 bolt is 2.56 / 2.73

12bolt truck axles all have 30 spline.
Carrier break is 2.73 / 2.76 / 3.42 / 3.73

Mine is a 10 bolt, 8.5" ring gear.  Looks like I'm good to go then. 
Thanks, Don