Ring Pinion Help Please

[stevel]

Have a 12 bolt rear end for 69 C10 with stock 3.45 gear ratio. Ordered a new Ring Pinion with 3.08 ratio.
The issue is my mechanic has torn axle apart and informed me I must use a new carrier for lower ratio. I am having no luck finding a carrier for this unit.
Kinda turned into an emergency as he now has his bay full with a truck that cant be moved. Really feel bad as he cant do any work till we get a new unit. Any help or direction will be appreciated.

[Overdriven]

There’s plenty of limited slip and locker carriers out there to buy new and have shipped quickly. Haven’t seen any new open carriers out there though.

[stevel]

Thanks. Is limited slip and locker the same as posi ? any leads on a good supplier.

[Mike C]

If you Google carrier break for a 12 bolt they show them at 2.73 and down, 2.76-3.42, and 3.73 and up. In theory at least, your truck would have the right carrier.

BUT, I haven’t seen 3.42 (which is the 12 bolt gear) in a 67-72 truck as factory. But you did see 3.54 gears in either a Dana 60 or a Dana 44. But again, Carrier break for a Dana 44 is 3.73 and down and 3.92 and up. Dana 60 (which their were some 1/2 ton use but not common) breaks at 4.10 and down and 4.57 and up. But they make gears in the 4.27/4.30 range so there is some potential confusion there.

Knowing that I would have your mechanic double check everything before you spend money on something that you normallly wouldn’t for a 3.42 to 3.08 change.

[stevel]

Thanks Mike. I will have him read the numbers on the teeth to check the ratio of gears he pulled out.
At this point all we know is the carrier in the truck will not line up for use with the 3.08 gears we have. The supplier I bought from said he ha a carrier that will work but it is a Posi. Carrier and cost around 500.00 . Cant believe that is my only option.

[applebmw]

Originally Posted by stevel

Thanks Mike. I will have him read the numbers on the teeth to check the ratio of gears he pulled out.
At this point all we know is the carrier in the truck will not line up for use with the 3.08 gears we have. The supplier I bought from said he ha a carrier that will work but it is a Posi. Carrier and cost around 500.00 . Cant believe that is my only option.

641 751 8060 Quick Performance I bought eaton posi for my 3.08 $430 shipped, everything I needed.

[stevel]

mechanic says the rear end is out of an early Camaro according to the numbers on the differential. Don't know which posi unit to use on this. the original gear ratio was a373.

[kwmech]

The only way this could have gotten messed up is if you got a passenger 12b ring and pinion instead of a truck R&P, or the other way. The truck 12b has only 2 carriers. the break is at 3.42/3.73.


Any proof of the Camaro origins?

[Mike C]

Originally Posted by kwmech

The only way this could have gotten messed up is if you got a passenger 12b ring and pinion instead of a truck R&P, or the other way. The truck 12b has only 2 carriers. the break is at 3.42/3.73.


Any proof of the Camaro origins?

The truck does have 3 carriers as mentioned above. There were some less than 2.76 gears in the 70's that used the 2 series carrier, but they are not common.

kwmech is correct though, if you have pictures with part numbers from the ring gear it will be easier to ID what you have.

[stevel]

It is a 3.73 . ratio. Spoke with tech at. Summit Racing for quite a while and we have come up with a posi carrier for it. Kinda pricy but I have to get it back on the road.
Cross my fingers.

[stevel]

Success with gear ratio change out. Lovin the new ratio clean and quiet.
Now my speedometer is off by around 10 mph slower than given speed. I know I need to update adapt new speedo gear. any suggestions?

Have a 3 speed manual trans behind a 250 straight 6.

[applebmw]

Originally Posted by stevel

Success with gear ratio change out. Lovin the new ratio clean and quiet.
Now my speedometer is off by around 10 mph slower than given speed. I know I need to update adapt new speedo gear. any suggestions?

Have a 3 speed manual trans behind a 250 straight 6.

I talked to my local family owned trans shop, been around 60 plus yrs, pulled plastic gear and took to them, they swapped me with a 2 tooth less, I believe. Have not drove truck yet, but I was reading 60-62 going 50mph. They said it should be close. Everything on the web was way off on saying what I needed...you can gear kits on Ebay, but you need to know what gears you have. it only takes 1-2 teeth for your application

[stevel]

Thanks for the info. I will try to find something on line that can be ordered. Or maybe local parts store can help.

[hjewell2]

Originally Posted by stevel

Thanks Mike. I will have him read the numbers on the teeth to check the ratio of gears he pulled out.
At this point all we know is the carrier in the truck will not line up for use with the 3.08 gears we have. The supplier I bought from said he ha a carrier that will work but it is a Posi. Carrier and cost around 500.00 . Cant believe that is my only option.

the guy next door to me has a 3:08 gear and open carrier he pulled out in the summer. I bet he would let it go. 1969 C10 8 /78 12 bolt