Mortorq

Is it possible to use 3:73 gears from a 4 cylinder S10 & retain the existing Camaro positraction to convert from the existing factory 3:08 1988 positraction.
It is the 10 bolt, not the 9 bolt Australian rear. I had read that the governor lock (grenade lock) type Posi in S10’s weren’t that great. Thanks.

sofakingdom

iTrader: (1)

Gears, yes. At a certain level, gears are gears.

OTOH, the "existing Camaro positraction" is almost CERTAIN to be a total piece of scrap metal. Not sure why any person with 2 or more neurons they could rub together and get a spark, would hallucinate that re-using one of those POSs would be A Good Idea, Especially if, their "existing" gear ratio, is 3.08 or lower. Since those gears won't install in such a situation. But if your rear axle currently has 3.23 or higher, they would bolt right in, then all you'd have to worry about would be, getting the pinion depth and carrier shimming right; and of course, whether or not (most likely not) the "existing Camaro positraction" was even remotely still functional. As they usually are NOT.

Mortorq

Gosh Sofa
At a youthful 65 yrs old, some of my synapses & neurons probably might NOT be firing just right, you have something there!
Thats why I’m asking! ��

The “existing”(should’ve said “present”)Posi is STILL working just fine though , although it’s a 3:08, not the required 3:23 as you mentioned to be able to convert to a numerically higher ratio.

So, respectfully Sofa, if I would like a 3:73 Posi geared rear end, what would your recommended course of action be,
besides finding a complete 3:73 Posi-equipped boneyard rear end & swapping it out?
Thanks

sofakingdom

iTrader: (1)

The 3.08 carrier supports gear ratios 3.08 and below. 3.73 requires a carrier for 3.23 and above. There are "special" "thick" gears to make up the difference but they are not stock.

Here's the difference. The ring gear flange is about .400" closer to the pinion on the 3 series. 2 series on the left, 3 on the right. The one on the left is probably what's in your rear. These are both Auburn units; not a very good part at all. Usually worn out within their 1st 10 years of life, often much quicker than that.



Here's how a S-10 "posi" fails... this is probably not what you have, but if you were to get one out of a S truck, this is the way its life would likely end.



You definitely don't want one of those.

If it was me, I'd get a new carrier and gears.

big gear head

This is the best deal that I know of with good parts in it. https://www.quickperformance.com/GM-...t_p_20409.html

Abubaca

iTrader: (3)

I know this isn't what you are asking, but if you're still running a low rev-ing TPI, you might not want a 3.73. Of course ultimately unless you're racing, and want every advantage, there is no WRONG answer. With my bolt on L98 I went from 2.77 to 3.27 and it was AWESOME! ....I have a different engine now, but it's still a lower reving TPI, and I just went to a new rear with a 3.42. While minimal, I do feel a little more performance (pull) in 4th gear, but I also find I have a few comfortable cruising MPH ranges that now require an upshift. I mean I'm right on the edge, but sometimes just a few more rpms requires a shift.

I'm redlining around 5500, and shifting a couple hundred less than that (give or take) and in my STREET driven car, no way I'd want a 3.73. -although it's certainly be fun. Sorry to stray off topic, especially with an "opinion" like statement, but figured it couldn't hurt.

EDIT....I see you've got a TBI car. Can't speak as to it's manners, soooo...feel free to disregard. lol

sofakingdom

iTrader: (1)

I suppose it would be worthwhile also to mention:

The gear in that grenaded Gov-Bomb is a "special" "thick" aftermarket one, and the carrier is a 2 series. You can see how much thicker that gear is than the one on the comparo pic above it. You can also clearly see how flat the back side of the ring gear flange on the Gov-bomb is; a 3 series would be more cone-shaped, like the 3 series above it.

This is why you can't put a stock 3 series gear like a 3.73 on a 2 series carrier such as is in your 3.08 setup.

Mortorq

Sofa, Thanks for your very thorough & pleasant clarification, especially the included pics of the differences 2 & 3 series carriers.

That S10 pic is certainly grim.

Thanks also, Big Gear Head, for the rear end parts source setup from Quick Performance.

Sofa,
As an aside, post retirement, the plan is to go from L03 to #6210 carb’d L31.
What are your thoughts on the Quick Performance 3:08 swap to 3:73 parts quality/selection/use?
Thanks

big gear head

The QP kit has a Yukon Dura Grip differential, USA Standard installation kit and the gears will probably be from Motive. These are all quality parts that I normally recommend for moderate performance use. They should hold up very well for a street car. It would be very hard to beat this deal for cost and quality.

Mortorq

Big Gear Head-
Thank you for that QP info.
Much appreciated.

Before the important exposed ferrous metal components in my midwest C3 succumbed to oxidation & had returned to the earth whence it came, the factory 3:70 gears were quite entertaining.

This aftermarket 3:08 to 3:73 Posi swap should wake up the future L03 TBI to carb’d L31 swap.

jmd

iTrader: (4)

For a street car that won't have the hammer dropped on it too hard, a 99-02 production F-body Torsen diff. is hard to beat.

They too, were made in "2 series" (3.08 and below) and "3 series" (3.23 and up) style. The latter would be in some automatics (optional rear gear LS1) and 6 speed cars.

Come to think of it, I don't know if a V6 those years would have one.

On the 3.73 choice, I always liked it, when matched with a 0.63 fifth gear. G/Luck w/ your build.

Mortorq

jmd.....

Another good idea with the Torsen there. Thanks.
‘99-02, pull the carrier & all?
My ‘88 has 26 spline axles , I think.

big gear head

You would have to replace the axles with '90-'92 28 spline axles.