[26634]

Hi guys,
I have a 69 coupe, 12 bolt rear, stock 3.31 ration. I plan to put in a more aggresive gear, but am unsure what to order. I have read about 3 and 4 series carriers, or whatever is the correct terminology, but don't know the difference or what I have. Can someone help enlighten me?
Thanks
rj

 

[cdnpont]

• 2 series - to 2.73
• 3 series 3.07 to 3.73
• 4 series 3.90 and greater.

Cheers, Mark.

 

[26634]

Thanks Mark,
So that means if my car came with a 3.31 rear, it has a 3 series carrier?
And if I want to put a 4.56-4.88 ring and pinion, does that mean I have to change to 4 series, or not necessarily?
Thanks for your assistance.
rj

 

[cdnpont]

Yes, a 3.31 would use a 3 series carrier.
I think ring gear spacers are available to run gears numerically higher than 3.73 on a 3 series carrier, but only to a certain point. The pinion gear becomes progressively smaller in dia. as you move numerically higher. 2.73 largest, 5.?? smallest. Hence, the ring gear must move towards the pinion gear an equivalent amount. You'd notice a difference in ring gear thickness between a 3.07 with the 3.73 being thicker. A 4 series carrier has it's ring gear flange closer to the pinion centerline than a 3 series.

BGH?

 

[L72/RS]

I would order a set with the thick ring gear and not use a spacer if possible.
JMO

 

[26634]

Thank you so much. Very helpful.
rj

 

[big gear head]

The difference between the 2,3 and 4 series is the location of the ring gear flange. Here is a picture that shows the difference.

Yes, you can get the 4.10, 4.56 and 4.88 gears to fit the 3 series. These gear sets come with a thicker ring gear to make up the difference in the flange offset.

 

[26634]

Thanks again everyone
rj