The 1947 - Present Chevrolet & GMC Truck Message Board Network

The 1947 - Present Chevrolet & GMC Truck Message Board Network (https://67-72chevytrucks.com/vboard/index.php)

- The 1973 - 1987 Chevrolet & GMC Squarebody Pickups Message Board (https://67-72chevytrucks.com/vboard/forumdisplay.php?f=4)

- - 3.07 gears???? (https://67-72chevytrucks.com/vboard/showthread.php?t=378911)

Re: 3.07 gears????

It's been a while, but I had the 3.0x gear in my 12 bolt and do not recall needing a carrier to swap to 3.73.

Re: 3.07 gears????

As far as I know, there is only a 3 and a 4 series carrier for a truck 12 bolt. 3 series is 3.42 and under, and 4 series is 3.73 and up. There aren't really that many gear choices for the truck 12, so it's pretty simple.

If you have a 3 series carrier, you can buy aftermarket thick gears that will let you run 4 series gear ratios on your 3 series carrier.

Re: 3.07 gears????

Quote:

Originally Posted by 78-5.3 (Post 3711850)

understand !!12 bolts are alot of hassle compared to a 9" i think i might start looking for a nine inch thats been narrowed down too around an s10 width for my future 4 bar set up i just wanna run lower gears till then!! these diesel gears are terrible

It sounds like the truck 12-bolt did not have a 2-series carrier like the car 12-bolt so you just need to find out where the gear ratio break point is for the carrier you have. A gear listing catalog would tell you.

Re: 3.07 gears????

Wow, how many hi-jacks can we have in one day?....LOL

78 5.3

Quote:

does anyone know what i need to change my gears to either 3.73 or 4.10 they are 3.07 at the moment do i just need the ring and pinion set or a carrier too? its open and im leavng it that way !!! i know there other need parts to buy ?

Yes you do need a carrier too.....and a professional to install it all for you. It's just not worth the time/effort and new tools required to do this "one time" job.

68TT

Quote:

If they break it down like the car 12-bolt carriers you will need a 3-series for 3.73's and a 4-series for 4.10's unless you run special thick gears on a 3-series carrier then you can get 4.10's on the 3-series. Can't get 3.73's on a 4-series carrier.

They don't....The break in the carriers is at 3.73. The 3.73 gears fit on a 4 series carrier and 3.42 is the lowest for the 3 series.

Pyrotechnic

Quote:

If you have a 3 series carrier, you can buy aftermarket thick gears that will let you run 4 series gear ratios on your 3 series carrier.

Yup, but I'm not a big fan. IF they still make them, there are ring spacers too, not a fan there either.

Re: 3.07 gears????

ok so i will need a 4-series carrier for my 3.07 !!! out of a truck !!! to make it a 3.73