Pontiac GTO Forum banner

1 - 9 of 9 Posts

·
Registered
Joined
·
45 Posts
Discussion Starter #1
Hello,

I need some help to ID a 10 Bolt GM Rear end, that has code DN (Delta Nancy) on the Axle Housing left tube upper,

On the right side of the axle housing tube, has the number - 3142, and then another number that is 8780100.

Some one has this rear end for sale, and is telling me it is for a GM A-Body '68 - '72, That is is a Posi rear end and has 3:73 gears

I am restoring a '69 GTO. Just would like to know if it fits...

I know that '69 GTO takes a 10 bolt rear end, and is supposed to be either 3:90, or 4:33 geared.

This particular rear end has been all gone through, and I can get it for what I think is a good price, but I would like to make sure that I know what exactly it is before I buy it.

I can't seem to locate any info on this on the Internet, all the links take me no where I need to go.

Can anybody help me to ID this rear end ?

Appreciate if could help

Thanks,

Lfryklu
 

·
Registered
Joined
·
714 Posts
Have you seen it? Can you go see it? There are several flavors of "10 bolts". You need to know if it is a BOP, or a Chevy, then you need to know if it's an 8.2 or 8.5 inch. do you have a pic of the diff cover you can post? Do you know the width (backing plate to backing plate)?

Also...think real hard about your rear end ratio... I thought 3.73 was ideal, until I had to live with it in the real world. If it were mine, I'd run somewhere in the 3.23 to 3.55 range and be a happy camper.
 

·
Super Moderator
Joined
·
5,146 Posts
Hello,

I need some help to ID a 10 Bolt GM Rear end, that has code DN (Delta Nancy) on the Axle Housing left tube upper,
D N should have an arrow between and indicates the shift the axle was manufactured, Day or Night.


On the right side of the axle housing tube, has the number - 3142, and then another number that is 8780100.
3142 may be the Julian date code which would be the 314th day of 1972 or 1982 or 1992,

Some one has this rear end for sale, and is telling me it is for a GM A-Body '68 - '72, That is is a Posi rear end and has 3:73 gears
If indeed it is a 3:73:1 it would be a chevy rear end, Pontiac didn't use 3.73:1

I am restoring a '69 GTO. Just would like to know if it fits...
If it is from a Chevy A-body it should fit.

I know that '69 GTO takes a 10 bolt rear end, and is supposed to be either 3:90, or 4:33 geared.
In 72 Pontiac offered the GTO with the 3.08:1, 3.23:1, 3.55:1 and 3.90:1 in the 10 bolt, the 3.07:1, 3.31:1, 3.55:1, 3.90:1 and the 4.33:1 was offered in the 12 bolt which was standard with the 455 engine.


The axle gear code for Pontiac should be stamped on the left axle tube. Also this axle may be the 8.5 corporate axle which is also available in 3.73:1.

Can you post a picture of the pumpkin?
 

·
64-67 Expert
Joined
·
8,569 Posts
In '69, you could also get 2.56, 2.78, and 2.93 rear gears in the GTO. 2.93 was the standard ratio with automatic trans and AC. For an automatic car, a 3.08-3.23 ratio would be ideal for all around use, and for a stickshift car, a 3.23 would be my choice. Even 3.55's are punishing above 60mph sustained speeds. BTDT.
 

·
Registered
Joined
·
400 Posts
Not trying to hijack this thread, but I am interested in these rear end codes. I just pulled a 12-bolt posi rear end off a 1969 GTO, 4 spd manual. I do not know the specific gears, but the previous owner believed it was 2.93. How do I go about checking what the gears are? Where are these codes on the rear end?
 

·
Registered
Joined
·
659 Posts
The two digit codes are on the right hand axle tube a few inches away from the pumpkin, they are about 3/8" tall, some are on the backing plate, but I can't remember if it's left or right. 69 GTO's didn't come with a 12 bolt, so that rear end could be just about anything. The original for a 69 would look like this.
 

Attachments

·
Super Moderator
Joined
·
5,790 Posts
Agree on the ratio. I'm running 3.50's in my 69 (it's a Moser 9-inch) and at 70 mph the engine is crowding 3300 rpm.

3.90's and 4.33's were way overkill in nearly everything except for Ram Air IV cars that were mostly raced.

Bear
 

·
Registered
Joined
·
45 Posts
Discussion Starter #9
In '69, you could also get 2.56, 2.78, and 2.93 rear gears in the GTO. 2.93 was the standard ratio with automatic trans and AC. For an automatic car, a 3.08-3.23 ratio would be ideal for all around use, and for a stickshift car, a 3.23 would be my choice. Even 3.55's are punishing above 60mph sustained speeds. BTDT.
Hi,

I found another 10" Posi rear end that has 3:08 gears.

I think you mentioned that you thought this would be pretty good for all around use.

Will be a 4 speed manual set up.

More thoughts ?

Thanks for your reply and comments

Lfryklu
 
1 - 9 of 9 Posts
Top