What was the standard factory differential for a 1970 W-30? Thanks for any help.

 

Auto or manual?

 

manual

 

3:42 or a 3:90 gear

 

3.91:1 gear ratio

 

Code Letters: "TO"

 

10 bolt or 12 bolt?

 

1970 would be an O-Type. 12 bolt cover and 10 bolt ring gear.

 

yes..thank you.. you are correct..😊

 

Got it, thanks!!!

 

I guess this is a stupid question, but is this differential typically called a 12-bolt, or a 10-bolt?

 

Better to refer to it as an O-Type and not get into the number of bolts argument.

 

It is typically (and incorrectly) called a "12-bolt" because most people don't understand that GM made rear axles other than the Chevy axles. A lot of people have been rudely surprised when they paid Chevy axle money for one of these only to find out it isn't. As Kenneth correctly points out, it is more correct to call this a Type O axle and avoid the confusion.

If your real question was what was the standard axle ratio, for a 1970 W30 MT car it was 3.42:1. Optional were RPO G88 3.91:1 and dealer-installed 4.33, 4.66, and 5.00.

 

defiantly some truth to this!!

when I bought my 69 back in 1987 I thought I really lucked out when I saw the 12 bolt diff cover. I don’t recall when or how I got the”wake up” about thr type o diff