differential gear change

[Tom Tarlazzi]

I have a 64 chevy c10 with a 12 bolt non posi rear and 3;73 gears. I want to go to 3;07 gears with my TH350 trans and replace bearings and seals in the process. I have never worked on a differential, and need all the help I can get.

[frankslagoon]

Hi Tom there are 4 different third members used in that rear end. 3:73 gears are the highest ring and pinion set you can use on that ser. third member. the next ser. goes from 3.42 to 3.07 I believe. Anyway. you can change the whole unit in there and use 3:07 gears but it probably will cost ya 500 bucks. Now if you have done any research you can see it's a bit tricky setting the gears up so they mess correctly. I would advice some assistance on first go around. Another option is to find a used rear end from a 63 thru early 70 with 3:07 gears and put new seals and bearings in.

[MySons68C20]

There is a wealth of info to be had here at this site and http://www.ringpinion.com/

[rickpilgrim]

You can get 3.08 but you'll need a different carrier. That change will take away a lot of low end.

[Captainfab]

If you change the carrier for your 3.07 gears, you will also need to change the spider gears in that carrier for the spider gears in your original carrier. This is because your '64 12 bolt has 17 spline axles, whereas '65 and up have 30 spline axles. You could also change the axles.

[frankslagoon]

Originally Posted by Captainfab

If you change the carrier for your 3.07 gears, you will also need to change the spider gears in that carrier for the spider gears in your original carrier. This is because your '64 12 bolt has 17 spline axles, whereas '65 and up have 30 spline axles. You could also change the axles.

Question Capt. can't we use the 17 spline side gears in the newer carrier ass.? I was glad to be rid of the old axles so never tried to use em. But ?

[frankslagoon]

Originally Posted by frankslagoon

Question Capt. can't we use the 17 spline side gears in the newer carrier ass.? I was glad to be rid of the old axles so never tried to use em. But ?

Sorry Capt. I guess that's is what your tryen say. Took awhile to sink in

[Tom Tarlazzi]

Thanks for the info. let me see if I got this right.along with ring and pinion, I need to get a series three carrier, but need to use 17 spline side gears to match my axles, as I want to keep the 6 lug pattern. can the series three carrier be bought with 17 spline gears installed?If not,can the 17 spline side gears from my 4 series carrier be installed in the 3 series carrier that I need to buy?