I was thinking of changing my gears on my 87 Camaro.. I have a 305 TPI engine in it that is going to be upgraded, but I was also thinking of upgrading my gears.. I have a 10 bolt 2 seriers carrier with 2.73 gears on it.. I was thinking more of 3.43 or something like that.. My question is, what is the best way to do it?..To change to a 3 series carrier with POSI for example and buy new gears? Or, to buy aftermarket gears that are thicker or to buy a spacer??? Is there any positive or negative thoughts I would like to hear them.. Thanks..

the best way would be to find a used carrier with posi and 3:42 gears already and swap it in.

or get a while rear and swap the entire rear. Which is probably easier than swapping gears and properly setting them up.

86 is right, the rear swap is the easiest (and no doubt the cheapest); however, finding one that meets your specific needs--brakes, gear ratio, working posi--may be difficult, especially in Norway. If the expense won't strangle you, you might consider a series III with an Easton posi and 28 spline axles.

JamesC

I know a lot of people think that it is difficult to change gears to make them right, and I agree to that for people who haven't been working on gearwheels to much...

I don't want to brag on myself, but I am actually working with gearwheels every day. I am working for Rolls Royce company and we use a LOT of pinion and wheels. And I am adjusting gearwheel,s every day with shims and have a lot of experience on them. I am also taking a lot of "tooth" pictures so I know this kind of operation, so I think that would be no problem to me...And again, not to brag of myself...
I haven't done it to a rear axle yet but the principle's are excacly the same.
"One pinion is driving a gearwheel around"

To get a rear axle here in Norway are about impossible because there are not much Camaro's here and if I am going to buy a whole unit the shipping quotes are very expensive...I think it would be better with a carrier unit then and a gearwheel set...

I intalled eaton LSD, new 3.23 GM gears, bearings and seals by my self with help of the service manual. Wasent too complicated, compared with cam swap and header install.

New posi, gears, bearings, ... will probably cost as much as shipping a junkjard axle over the pond.

Maybe, fist decide if you whant to keep the 26spline axles or go 28spline.

If your two series posi is good, then new aftermarket gears for a two series carrier will be fine. There is nothing wrong with a thick ring gear, ring gear spacers are not a good idea, but thick gears have no disadvantages, I would just buy the thick gears and install kit. Setting up gears is not hard, if you get the pinion depth right, then set your backlash, everything else will fall into place.

I am sorry, I didn't mention it earlier but I have just a open 2 serier carrier...Not a POSI unit..But I guess swapping to a POSI unit would be better, since this was a optional package on the Camaro's...

I think the cheapest way will be to buy a 3 serier carrier posi unit from ebay...And buy the ring and pinion set after that...

When it comes to the spline axles I think it is the best to just keep the 26 axles...If I am going to change to 28 spline axles what would I have to do?

Change the bearings so they would fit 28?..Will 28 axles fit on my rear unit??

The following should provide some helpful info:

http://www.thirdgen.org/techboard/tr...-10-bolts.html (FAQ About 10-Bolts)

JamesC

wooow...A great link...Thanks a lot..I get all the answers I've been looking for there...

or u can find a borgwarner 9 bolt posi with a 3:27

Of course but those are hard to find..Especially here in Norway...And they are a little expensive if I am not wrong?..

The 3 series Eaton is the best way to go (No Auburn). Get a set of gears and a good installation kit. A good installation kit will make the job easier. A bad installation kit will cause you to pull your hair out. I do not recommend the Rayech, Summit, Jeg's, Richmond and other cheap kits. DTS, Tom's Differentials and Yokon have the better kits. The same goes for gears. If you buy cheap gears then you better expect them to be noisy. When it comes to rear end parts you get what you pay for. If you buy cheap stuff then you aren't going to be happy with it.

If you can find a two series posi cheaper for you rearend, I would buy it.


In a rear like the gm 8.5 ten bolt,, two series posis are just about worthless, the only way to use them is with a ring gear spacer. This is because nobody makes the "thick" ring gears for some reason. But one of the very few benefits of the 7.625(7.5) ten bolt is the availabilty of these "thick gears". which means you can use a two series carrier with 3 series gears with absolutely no drawbacks.

I have had great experience with all the Auburns that I have run, they have great breakaway tourqe, and now that they offer a one year warranty, followed by a three year d-rex warranty, I would not hesitate to buy another.

The d-rex program is where if you wear out your posi, or break it in any way, within four years, they will replace it for the cost of replacing clutches in a competitors carrier. This is a no questions asked policy, so after about 3.5 years on mine, I will check the breakaway tourqe on mine. If it has lost even ten pounds, I can send the unit off and get it replaced for around 80 bucks. Sounds like a winner to me.

Have you ever removed a worn out Auburn? As they wear they fill the rear end with powdered metal, which goes through all of the bearings and gears. This requires a complete rear end rebuild and axle replacement. I have seen Auburns that didn't last 3 months and I had to scoop out the metal from the bottom of the housing and out of the axle tubes. The replacement program doesn't pay for all of that. They also pop and chatter much more that other differentials. I just like the Eaton because it lasts a LONG time (30 to 40 years in some of the old muscle cars), doesn't fill the rear end with metal, is rebuildable and can be tuned to fit your needs.

Where exactly does the clutch material go when a eaton wears out. Many gm cars came out of the factory with auburns, and they served there owners well. If I had an auburn, or an eaton that needed servicing, I would replace all the bearings anyway, I think most anybody would, so that point is moot.

I've rebuilt a lot of Eaton units and there is very little metal in the oil. It's almost un noticable. A small magnet attached to the inside of the cover can easily catch the metal that is put off by the Eaton. The old Eaton uses hardened steel plates that wear very slow and put off little metal. They become slick and that is usually the only reason that they need to be replaced. The new Eaton uses carbon fiber lining on the plates and it almost doesn't wear at all. They do glaze if they are slipped a lot. I replace them with the steel plates.

The Auburn fills the rear end with metal. It's amazing how much metal comes out of one of them. The cones and case are not hardened and the metal wears very quickly. There is MUCH more metal that comes from the case wearing and a magnet could not hold anywhere near the amount of metal that they produce.


These pictures don't show the amount of metal sludge that was in this rear end after about 3 months with this Auburn. The axle tubes were also full of metal sludge. I couldn't get the camera in a position to show how much was in it. The metal was about 3/8 inch deep in the bottom of the housing.

The factory camaro 7.5 rearends came with an auburn posi, I have seen many of these go over 100000 miles without destroying the bearings with all of there metal fillings, as a matter of fact, I have never found a considerable amount af shavings in these rears after those 100000 miles, The exapmle you post must be from a deffective unit, or serious abuse, either way the same thing could happen with any carrier.


I will agree that over the long haul an eaton may be a better buy, a worm gear unit may be a better buy than either one, but I have no first hand experience with them. I am just pointing out that with my experience, Auburn have always been reliable and I have never seen a rear end filled with shavings from one.

A lot of good suggestions here...I guess I just have to choose one, when I am going to buy...But I think now I just have to focus on other things at my car first..

I have had a few problems with transmission and the TPI system so after that I will go on with the rear end...But thanks a lot for those great comments..