i have an 89 rs with a 350, 3000stall in a 700r4, 4.11 and an alburn posi unit. bought the rear end off a friend and was recently driving casually down the road when a wineing noise began to emerge from under the car. i started crossing things off the list to then discover i had somehow remover a few pinion teeh off the richmond 4.11.1 gear set that was installed into the car. nothing had lodged into the gears and the fluid was still a good color. so now im trying to buy a new set of gears and was woundering what the spline count was on the 7.5/7.265 and should i go with a 3.73 since its part d.d and a ocasional racer. also what is the difference in the 2 and the 3 series carrier? thanks

 

Your questions should be answered in the following FAQ:

https://www.thirdgen.org/forums/tran...-10-bolts.html

JamesC

 

thanks for that thread but theresone thing im a lil fuzzy on, figureing out what carrier series i have a 2 or a 3, since the auborn carier was put in and 4.11s were added how do i find out what series i have and what carrier series 3.73 to buy. thanks

 

I'm tired of repeating myself; but at the risk of sounding like a broken record, the only way to know FOR SURE what your axle splines are, is to TAKE OFF THE COVER AND LOOK. Above all that applies to 89, since it was the changeover year; probably 80% or more are still the older 26-spline, but a few got the new 28-spline. Only way to know is to look.

2-series carriers locate the ring gear farther from the pinion CL. THINK about "ratio" for a minute... it is NOT ONLY the tooth count, BUT ALSO the gear diameters. But since the ring is always the same diameter, then as the ratio increases, the pinion diameter must decrease. So if you imagine that you're designing a rear end model, then what you would do, is start out with the lowest ratio that it will ever accommodate; determine, based on all of the mfg constraints, how thin the ring should be; and locate the flange on the carrier that the ring mounts to, accordingly. Then as the ratio increases, the pinion diameter will decrease, and the ring thickness will have to increase. Eventually you'd get to a point where the ring would be just stupid thick, and hard to make because heat treating would warp it; so at some convenient point in the progression of ratios, you'd move the carrier flange over toward the pinion, and start over with a thin ring, and then as the ratio continued to increase, the ring would once again get thicker.

In the 7½" 10-bolt, there is only 1 break in the series; and that occurs between 3.08 and 3.23. 3.08 and lower is 2-series, 3.23 and higher is 3-series.

There's about .350" or .400" difference (about 3/8") between them. The 2 series has it so close to the carrier bearing that the flange looks kind of flat, where the 3-series locates it so much farther away that it looks sort of cone-shaped.



2 on the left, 3 on the right.

Note that these are both crappy Auburn ones; the left is stock one (pic taken by someone else, I apologize for the quality, I merely stole it), the right is a "high-perf" I used to have (I think I finally got tired of looking at it laying around uselessly and threw it away), which you can tell by the extra springs. It's still garbage. But you can EASILY see the difference in the location of the flange, compared to the carrier bearing.

 

Since the change was in '89, maybe all owners of an '89 Camaro, who have actually counted the splines on their axles, can post what they have.

 

The change was in 1990. A few late 1989 cars may have got the 28 spline axles but the majority of them got 26 spline.

By changing the carrier (posi) to one for 28 spline axles, any third gen 10 bolt diff can get 28 spline axles installed. The only factory axles that will fit are from 90-92 third gens but aftermarket 28 spline axles are much stronger.

 

I really hope mine is one of those late '89s then.

 

You'll need to find the build date of the car.

 

im new to all this gear ratio and carrier stuff so if i sound like a broken record or stupid sorry in advance, i was looking at the underside of the axel and saw some numbers, i know one was the axle code that probably wont help me but on the passanger side there was a c with a 28 next to it and had a crossed out circle in it, does this mean nothing or is there something to the numbers?

 

Most of the casting numbers on the diff mean nothing except to someone building a date correct and numbers matching vehicle.

The axle code is stamped into the front of the passenger side tube near the center section of the diff. They're usually very difficult to find and read. All that will do is tell you what gears were originally in the diff and if it was an open or posi. You can take the diff cover off and check that.

If you want to know the spline count of the axles, pull an axle and count them. That's the only way you're going to find out.

 

Just pulled my axles and counted the splines. 26 splines

 

When I did the upgrade on my "89" rear end I also was hoping for the 28 spline axles. No such luck . Ended up buying new 28 spline axles to fit the 28 spline Eaton. Just another $250.00 to the bill.

 

As mentioned above, 1990 was the changeover year. Only a very few 89's got 28 spline. The majority got 26 spline. It will all depend on the actual build date. Basically if you have a 1989, you can generally expect it to have 26 spline. The only way to know for sure is to pull the axles but don't bet on it having 28 spline axles.

 

Which place did you get the new axles from? Used ones would have to be out of a '90-'92 Camaro only?

 

Someone has a pair of 28 spline axles for sale in in the classifieds on this site fyi.

 

Summit. Yes, but I'd be somewhat hesitant about buying used. Check the pic in the following link (you can see where the bearing rode on the axle).

EDIT: https://www.thirdgen.org/forums/tran...ing-axles.html

Thanks, Tobias.

JamesC

 

Mr James you left your link out.

...it'd be easiest just to buy new axles. That way you're starting with a clean slate. I recommend Superior axles.

...I also recommend not throwing money into a 10 bolt. I've put enough into mine I could have purchased a strange s60 by the time I got it running correctly.

 

www.tomsdifferentials.com

 

I'll search, but one set just sold.

 

http://www.summitracing.com/parts/SAG-EV10-4/

 

Perfect! I swear that I did a search on there and that didn't come up.