well about two months ago i bought a rearend from an 85 trans am. i thought it was going to be a 10 bolt, but turns out after i started taking it apart i realized it was a freakin 9 bolt. i didn't even notice it until my buddy asked me why it only had 9 bolts instead of 10.
anyway my plans have changed. my main question is, after looking at the tech articles i don't see a 3.08 ratio anywhere. i haven't actually counted the teeth and did the math, but 3.08 is stamped on the ring gear. is that a used ratio in tis rearend? also i'm looking to put 3.7x ratio gears in (whatever is available),
is there a difference in carriers like in the 10 bolts i.e. II and III series, or is it all the same? i was expecting to pay an arm and a leg for parts since it's such an off the wall rearend, but it looks like i'm not going to pay too much more than a 10 bolt.
thanks for any help.
kent

 

Bummer....

There were 3.08 those, but they're not common. It would be worth knowing what drive train the donor car had; LG4, L69, or LB9, and auto or stick.

Yes there are 2 series and 3 series; the break is between 3.08 and 3.27. So yours would be a 2 series.

AFAIK there are no "special" thick gears for the 9-bolt, or even ring gear spacers, although I could be wrong about that; meaning, you pretty much HAVE TO HAVE a 3 series carrier to put 3 series gears in one. Needless to say, finding one of those in good shape is not that easy, and they're not cheap. Go through the classifieds on this site and see what's there.

 

not sure what was in the car to begin with, i know for sure it was an auto, maybe a 305 tpi? well i'm sure you have seen these gears before http://www.yukongear.com/ProductDeta...px?ProdID=1208
i found these, but they don't specify what carrier they are for. i sent an email to them asking, but i'm not holding my breath. so pretty much i'm screwed for getting gears. man i wish it was a 10 bolt.....

 

It's just like Sofa said, those Yukon gears are only for the 3 series carrier. In fact, that's another downfall about the 9 bolts, the only aftermarket gear ratio available for them is 3.70/3.73. 3 series 9 bolt carriers do pop up in the classifieds here fairly often, and also on ebay here and there, so if you keep your eyes peeled, you should be able to get one. Keep in mind though that you'll be buying a used posi unit, and it probably won't last too long. The 9 bolt posi units are known for going bad. In all honesty, I'd just run it with the 3.08's, and replace it with a good 10 bolt when you can find one. If you don't mind the extra width, 4th gen 10 bolts with 3.23 or 3.42 ratio, posi, and disc brakes are pretty easy to come by.

 

that is what i'm going to do. even with the 3.08's it's still better than my 2.73s. and i'm also getting a limited slip with disk brakes. i just hope the diff doesn't break on me. the car was setting for 3-4 years but the fluid didn't look half bad when it came out.

 

somebody from yukon gear got back with me, and said that if i had the 3.08 gear ratio, then their 3.73's will work.
thoughts?

 

Get it in writing; have them guarantee that they'll issue full credit if they dion't fit; make sure they'll pay the freight both ways.

Then all you're out, is a bunch of bearings, fluid, time, tools, and so forth. But at least you have somebody that'll join you on the hook.

 

Hey it's a double edged sward. You got the stronger set up- but it's expensive and hard to find parts for. Do a search. There are good links to sources of new parts. Yes most all ratios are available new. I think they have to come from Australia but you can get them.

I have a 9 bolt and when I looked I found no sources of thick gears for the 2 series carriers. Maybe they are out there but I could not find them. I ended up buying used off ebay and found plenty of 3.27 gear sets available. I had to also buy a complete rear end to get the 3 series carrier. Then I sold the extra gears and housing and came out to the good. I think I paid $75 for a used set of 3.27's and they've been running quietly for a couple years.

If I were going to completely rebuild my 9 bolt with new parts etc. I think I would be better off financially (and strength wise for sure) to get a special made 9" or 12 bolt with preferance to the 9" Ford.

FWIW.

 

i'm still going to put it in as it is with the 3.08's. i was just surprised that he said the 3.73's would fit. maybe a possibility that since the 3.08's were so rare that they could be a III series carrier? like i said i'm still using it as is, because for all i know the first time i go drive it the diff grenades....no sense in polishing a turd by putting money in it.
kent

 

So what did you end up getting / doing?