[bradley fideldy]

Ok, brought a 66 GTO home yesterday, was told it had a low gear 10 bolt posi in it, so I got it jacked up and checked it out. Pulled the cover off and it doesn't have the usual 4 springs in it. It has at least 6 springs. You can see 3 right next to each other on both openings of the carrier. May have more than 6, but you can see 6 for sure. Turned the yoke and went around 4 1/2 times before the tire came back ? Thought I counted wrong and thinking it was a 3.55 gear ratio......I tried it a couple more times. Comes out to approximately 4.5:1 gear ratio. Anybody know what this posi with extra springs is ? There is some engraving on the ring gear, bunch of numbers and letters. Rear is 55.5 inches from backing plate to backing plate ? Anyone know what its worth ? Anybody looking for one ? Little to low geared for me. Anybody want to trade for a 12 bolt posi in the 3.90-4.10 gear ratio with a little cash to boot ?

[baron_]

10 bolt or 12 bolt?
location?
those numbers and dletters on the ring gear tell exactly the ratio

take a picture or jot them down and post on here and we'll help

if it has anything over a 4:00 - it won't be driving on the highway
(i don't know if you can drive to test)

i've got a spare 3:55 and a spare 4:56, both posi's


also, on the passenger inside frame tube, if you scrape you'll find numbers - they'll tell year of the rear...what gear it came with, etc

[bradley fideldy]

Ok, heres the pics, the posi is a 10 bolt on the cover and 10 bolt ring gear. You can see 3 springs through each hole.....so at least 6 springs, can't see if there is more in there...not much for visibility. The number on the ring gear is, 1518N BL006 010. The B might be a 13. By turning the wheels it looks like it is a 4.56 gear. I have never seen this 6 spring type posi before though. Any ideas what exactly it is

[baron_]

could you back away with the pictures a little?
and the numbers you need are on the side of the big ring gear
they're cast into it - small

move away the oil and you'll see them - i don't know what those hand-written numbers are


kinda looks like there's a spacer, if i'm seeing that right
which means you have a 3 series carrier most likely, and a spacer to fit 4:56 gears in it
that could be a good thing....just buy whatever gears you want for it and slap 'em in


i included a picture of the 12 bolt posi 4:56 i save, where you can see a spacer....
andd also you can see the numbers i need you to find on the ring gear - which tell exactly if it's a 4:56 or whatever (although you already pretty much know that)

the other picture - see the scratched off area?
that's where you need to look on the tube of the axle...to find the codes on that to tell what kind of a car it came out of


i'm not good enough to ID that carrier by picture - with so many aftermarket ones andd whatnot
maybe ID'ing the rear will help - see if it came out of an oldds - etc

[mchell]

the BL006 010 on your ring gear is the minimum and maximun backlash recomended by the manufacturer, in this case a .006 to .010...

Posi case does look like it has a spacer..........could be a Traction loc......

[bradley fideldy]

Ok, here are some more pics. Ring gear has a few numbers, looks like B9V 7206 and the axle tube has a WH code on it. The ring gear appears to have a spacer plate behind it, at least what I would assume is a spacer. Anybody know anything about this. I want to change gears in it, or sell it and buy a little more streetable posi, preferably 12 bolt 3.90 or so

[azmotorhead]

Looks like a (edit) trac lock rear carrier. Definately not a Eaton unit. COunt the teeth on the ring and pinion gears,& we'll give you a definate ratio.
Look around the bolts of the ring gear you may see a P/N or logo of the manufacturer

[Geoff]

The original Pontiac 10 bolt Safe-T-Track used 6 springs, not 4, so it could be original. WH code on a 66 GTO is 3.55 ratio. Ratios from 3.36 & numerically higher used the same carrier. I suspect you have an aftermarket ring & pinion, which would explain the spacer.

[Geoff]

Another explanation for the use of the ring gear spacer is using a lower
[ numerically ] ratio carrier with a higher ratio ring & pinion.