I have a nine bolt drum brake open diff and have located a 3.42 posi ten bolt that needs a pinion bearing I could probably pick up cheap like under $100 should I buy the ten bolt or just upgrade to a new carrier and the 3.45`s in my 9 bolt it has 3.08 gears now.

 

Are you sure you have a 9 bolt with drums and 3.08 gears?I have never heard of a drum 9 bolt or a 3.08 gear in it.10 bolts had drums3.08's though.

 

you should go with the 10 bolt and fix that bearing and use that, they are cheaper for to buy parts for and are close to the strength of a 9 bolt..

since it already had the 3.42 gear with posi your all set.. 100 bucks is good verses the price to fix the 9 bolt..

 

9 bolts ONLY came with 3.27:1 gears, posi and disc brakes and have a ring gear of 7.75" instead of 7.50" for the 10 bolt. 10 bolts are fine in a stock car but I took half the teeth off of the gears twice and broke an axle in 3 pieces before I installed a 12 bolt! no more problems

 

9 bolts came with 2.77,3.27.3.45,and very rarely 3.70

 

Ed
AND 3.08s...ask Miles at diffsolutions.com and my factory service manual.

No lie, they're out there.

Ed

 

A 7.5/7.625 10 bolt is nowhere near the strength of a 9 bolt!!!
All the 9 bolt info you need is at www.9bolt.com

Miles
Diff Solutions
www.9bolt.com

 

Steve86ta I too believed that all 9-bolts were posi disc units until I crawled under my car for the first time and saw the borg-warner cast into the bottom of the housing and realized there was a rubber plug in the cover and until I went to 9bolt .com I believed that I had a posi someone had burnt the cones in. Thanks to everone on their input keep it coming still haven`t made up my mind would like to here from people who may have had both and see what they think.