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View Full Version : Unable To Put 3.73 Gears In My 10 Bolt????



novajess1972
12-15-2012, 05:16 PM
Have non posi GM 8.2in 10-bolt 28 spline in the rear of my 72 Chevelle with 3.42 gear ratio. Want to order a limited slip diff to wake up both wheels. Since its already going under the knife, I figured I'd go from the 3.42s that are currently back there to 3.73s.

DILEMMA: Every ring & pinion that I see seems to not have the spline that I need....28 spline. I see 17 pinion spline, 25 pinion spline, 27 pinion spline, 30 pinion spline, etc.

What gives? Do the ring & pinion folks not want me to have 3.73s in my 10-bolt???

UNGN
12-15-2012, 06:03 PM
"28 Spline" usually refers' to the Axle spline, not the pinion spline. Most 10 bolts are 28 spline. That doesn't have anything to do with the Ring/Pinion.

The Pinion spline would depend on the driveshaft yoke spline count.

novajess1972
12-15-2012, 06:05 PM
"28 Spline" usually refers' to the Axle spline, not the pinion spline. Most 10 bolts are 28 spline.

The Pinion spline would depend on the driveshaft yoke spline count.

Okay...that's what I wanted to confirm. I didn't want to assume those were referring to the same and had to match.

Thanks!

UNGN
12-15-2012, 06:51 PM
28 Spline is the typical std axle spline and 30 spline is the typical upgrade spline.

With a 3.42:1 carrier, the 3.73's should go right on.

novajess1972
12-15-2012, 09:21 PM
Great! Thanks for the clarification!!

SShep71
12-16-2012, 02:24 AM
For future consideratin when you are doing a gear change another thing you will wnat to consider is the carrier offset. Some carriers have offsets due to the depth of the ring from the machine surface on the back to the ring to the "teeth" cut on the front. That may determine what gears you can change too. Just an FYI, ya never know

novajess1972
12-16-2012, 11:50 AM
Disregard. Found my answer.

TheJDMan
12-16-2012, 03:55 PM
Why spend all that money on a 10 bolt? IMO, you would be better off spending a little more and buying a complete 12 bolt already setup with your preferred ratio and in the width you want from someone like Moser or Strange.

novajess1972
12-16-2012, 04:37 PM
Why spend all that money on a 10 bolt? IMO, you would be better off spending a little more and buying a complete 12 bolt already setup with your preferred ratio and in the width you want from someone like Moser or Strange.

Money is tight right now with Christmas and school tuition/books upon us...and not to mention the wife has been hinting for a ring upgrade.

This should satisfy the urge for now. I can get a full setup further down the road. If any of the site sponsors here offer member discounts, point me in their direction and I will at least explore the option.

AmKenpo1
12-17-2012, 06:43 AM
Your "8.2" 10 Bolt should have 25 Spline on the pinion shaft.

Wil.

Skip Fix
12-17-2012, 09:16 AM
Usually in the Richmand catalog they have the pinion spline counts on the gear sets. Teh old 55-64 10 bolt pumpkin rears had 17 spine axles adn a really low pinion spline count also.

Just remember that 8.2 is not the strongest 10 bolt.

novajess1972
01-28-2013, 12:35 PM
Thanks for all the input, guys. I ended up snagging a 12 bolt from my uncle on the cheap and had a local shop clean it up and load 3.73 gears in. It's a limitied slip unit.

Damn, what a difference! The combination of both wheels engaging and 3.73s really woke up my old girl. I think I need new rear tires already...and only had it back from the shop for 3 days.

JW