I have an 89 IROC with a 10 bolt 2.73 posi, I'm looking to get a new ring and pinion set (3.42's) my question is my rear end is a 28 spline correct? I ask because I have only found one ring and pinion set that is 28 spline. Also will my original carrier work? http://store.summitracing.com/partde...5&autoview=sku
that is the set I'm looking at. Any input? Thanks. James

 

You have a 2 series carrier. In order to use any gears above a 3.08 you need a three series carrier so no your current carrier will not work.

 

Thanks for the info, looks like I might just end up buying a used rear end.

 

What he said. Also, I don't think splines went up from 26 to 28 until 1990 though, when they started being 7.625" rather than 7.5".

This is the Worm-gear style Posi for 3.23 to 4.something.
http://store.summitracing.com/partde...5&autoview=sku,

and you'd also need 28 spline axles:
http://store.summitracing.com/partde...5&autoview=sku

Now, that's $750. Just axles and carrier. Now, if you buy used, you can save some money. They made a 28 spline Zexel Torsen that went in the 98+ F-bodies, and it's a bolt in with the right 28 spline axles. Junkyards around me want $75 an axle, so you might wanna spend the extra money on the Mosers.

Or, you might want to consider buying a 10 bolt that already has 3.42's. Was that a factory ratio? I've got 3.27 in my BW, and I know that some of the 10 bolts were 3.23.... Either way, you can usually get a whole axle for $100-$150. They're big, heavy, and people want them gone. Look for one from a 90-92 car if you want one in thirdgen width. 28 Spline axles, better brakes. Get one from a 93+ car if you think that the slightly wider stance looks good.

Or if you have the kinda cash sitting around, buy an aftermarket rear. I like the D60, because it's probably twice as strong as anybody needs, and it doesn't cost too much more than any of the other aftermarket rears. I think the exception here is the 9", 'cause someone pointed out a ready to bolt in 9" for around $1500.

 

If you want to use a thirdgen rear with 3.42's get a v6 rear. If you want 3.73 get either a L69 rear or one out of an Iron Duke thirdgen.

 

if you already have a posi, then it doesn't matter what splines you have, 26 or 28. You can get 3.42:1 gears that go on a 2-series carrier. The best come from Richmond Gear, and I think SDPC carries them, but if not, try summitracing.com or jegs.com

 

Ok, now I am a little confused, so I can put 3.42's in my series 2 carrier? I have a 2.8 with a 3.42 but I would like to keep my posi, I wish I had the money for a whole new carrier, if I cant just swap the ring and pinion I am just going to look for a whole rear. I dont really care if its a 4th gen or 3rd gen rear end.

 

They do make 3.42's for a 2 series carrier, but the ones you showed are not for one. The cheapest route to go would be to buy a whole rear end if your looking to upgrade to 28 spline for a little more strength. If your looking to just swap gears than find the set of richmonds for a 2 series carrier. If your looking to upgrade your whole rear than get a newer one with the gears you want. Sorry for the confusion in the first reply i made, i really meant to say those gears wont work for your current carrier.

Right now your trying to put a 3 series set of 3.42s on a 2 series carrier which will not work.

Just for the info, a good used rear from a JY can run anywhere from 300-600$.

 

Ok that makes sense, I will look for for a set of richmonds for series 2 carriers, I would really like to just to keep my rear as I know the posi and everything is tight.

EDIT: http://store.summitracing.com/partde...5&autoview=sku Will that be a direct swap?

 

Those are right for a 2 series carrier, however im not too sure why it says 27 splines. Im pretty sure everything is 26 or 28 spline.

 

check randysringandpinion.com or google it, its where i get most of my diff stuff. im not advertising that site or anything, i just think its more user friendly than summit racing, when it comes to rear end gears

 

Okay thanks everybody for the quick reply's, it always makes life a little easier. Anyway, I will check out randyringandpinion and if I cant find what I'm looking for I'll just end up calling summit or richmonds tech line and asking them about the whole 27 spline deal. Thanks again. James

EDIT: http://www.ringpinion.com/ProductDet...px?ProdID=1066 It says "This is a thck gear fr a 3.08 & down carrier." Does that mean series 2? Mine is a 2.73, it doesnt specify down numerically or ratio wise. I spose I will give them a call in the morning.

 

The 27 spline is referring to the pinion gear. It splines to the u-joint yoke. The u-joint yoke has 27 splines in it. Hope that clears it up.

 

You learn something new every day lol. And yes a 2 series carrier came with 2.73 and 3.08 gears. A 3 series came with 3.23 and up. So if it says for a 3.08 carrier than those are the correct gears for you.

 

Sweet so the whole "27 spline" thing I dont need to worry about? Well thanks again. Get to keep my rear which I know is all good.

 

you also can buy a ring gear spacer to put higher gear ratios an a diffrent series carrier

 

Sorry to bring this back, but I have a question on the richmond gears I am looking at http://store.summitracing.com/partde...5&autoview=sku, under the required parts there is a cross shaft, I have not seen one other set of gears that have this even under the suggested parts. Can anybody elaborate????

 

It could be because you're putting "specialty" gears into the diff, and it might need a different than stock cross shaft. Call Richmond up and ask. If there's one thing I've found, it's that companies love selling stuff, and they love answering questions so you can be informed about your purchase.

Strange Engineering faxed me a data sheet on some of their drag brakes for no cost. If in doubt, call and ask.

 

The reason for the special cross shaft is that the ring gear is too thick for the cross shaft to be reomoved. The gear actually covers part of the hole in the case. The special shaft has a flat cut into it so that it can slide out over the teeth of the gear enough to get the c clips off of the axles. This shaft MUST be installed before the ring gear is installed on the case. I have used stock cross shafts and ground a flat on them myself, but you need to know how much to cut off. You need to cut off just enough to allow the shaft to slide out a little, but not to make the shaft any weaker than it needs to be.

This shaft is not needed in some of the applications that are listed. They just recommend it in case you might have a problem. I have found that some of them only need a very slight cut in the shaft, where some need quite a bit removed. I have never needed to do this with a 3.42 or 3.73, and I don't think it's needed (can't remember) with a 4.10.