All,

I just found out that I need to replace the ring & pinion gears in my 8 3/4 rear. I currently have a sure-grip w/ 3.23s. I'd like to maintain that gearing.

Problem is, I can't seem to find these gears new. I've looked at Dr. Diff and at Randy's Ring & Pinion, but 3.55s are the lowest gears they offer. Worse yet, I was told by Randy's that I would need a new yoke because their gears don't match my current yoke's spline count.

So I'm looking for used. When I look for used, I see different spline #'s, and I don't know which one I need.

I'm a fish out of water when it comes to the inner workings of the differential, so any help/advice is appreciated. What should I be looking for? Is there a cost effective way to replace just part of the 3rd member?

Forgive any stupid questions.

Thanks.

Jim

They make a fine and a course spline yoke and they make two different size yokes, a small and a large. The only way to tell what spline setup you have is to pull the pinion nut and washer off.

If you don't want to replace your yoke then find a used ring an pinion set that has the same spline count that you already have.

That is a pretty common gear set. As a last resort you could probably buy a set of 3:55 or 3:91's and trade someone for their clean used 3:23's.

I think this is your answer to not having to take it apart.

If the pinion nut takes a 1 1/8 socket, it is a 10 spline. If the pinion nut takes a 1 1/4 or 1 5/16 socket, it is a 29 spline.

mancini has what looks like NEW 489 gear seats , 2.94 AND 3.23 . the yare 10 spline , but it's no big deal to change the yoke .

there is a guy who sells third members at the long beach swap meet , he has a spot there I cant remember is name. i got a 2.76 sure grip cheap from him.

10 spline or 29 spline

and there are 3 u-joint size

2 1/8" = 7260

2 5/8" = 7290

3 5/8 = 1330

my 67 polara-742-3.23-open has the 3 5/8" 1330 u-joint and course 10 spline

the 73-newport 489-3.23 open has the 2 5/8" 7290 course 10 spline

the 74-489-3.55 sg has the 2 1/8" 7260 29 fine spline

for example...

not that much diff between 3.23 and 3.55,IMO

but 3.91s are a night and day differance

when its toast,and not a 4x4 thats got to match a front diff

any working one is good,IMO

used=resulst will vary

like auto trannys,they look good sitting on the shop floor all clean and all

priority and no budget is my moto

good luck

I'm in so cal and have a nice 3.23 489 set with 29 spline... PM me if that's what your after

You could alway just install the 3.55 and get a taller tire.