MachinistMark

I have an 85 lg4 auto trans t/a with a 9 bolt. No idea as to the ratio. According to the thread on here, any gear higher than a 3.08 goes in a 2 series carrier. According to the owner of 9bolt.com only 2.77 gears go in the 2 series carrier.

Who's mistaken in this?

RedLeader289

iTrader: (2)

Idk if the tech data on this forum is correct, because on one thread ppl are saying that the TAs got 9bolts in 85 but on the tech data it says that it didn't happen until '86.

Either way, if you have a 2 series carrier and want a better gear you'll have to swap up to a 3 series carrier (if you want 3.27s, 3.45s, 3.70s). So are you just inquiring for your own information or are you wanting to do a gear swap?

There should be a number stamped on the passenger side axle tube of the rear end and if you do a search it will tell you exactly what you have.

I have always heard that the 3 series carrier starts at 3.27 with the 2 series being the 3.08 and 2.77s.

MachinistMark

Glenn, owner of 9 bolt.com, says ONLY the 2.77s are 2 series. So that's my confusion. I want to go to a 3.90 gear (available from 9b.com) but if I'm gonna have to swap carriers i think I'll just look for a 3.73 posi 10 bolt.
More than anythong im trying to clear up what seems to be so.e misinformation on the subject.
http://www.9bolt.com/gearsets.html

RedLeader289

iTrader: (2)

Well, I'd say go with what the owner of (as far as I know) one of the only parts suppliers for 9bolts says then.

First you need to figure out what gear you even have. Do you have a tag on your diff cover? (should be held on by one bolt) like in my attached pic towards the top right of the picture.

I'm not near mine at the moment but i think it has the gear ratio stamped onto it

RedLeader289

iTrader: (2)

Also if you wanted a 3.73 gear for the 9bolt this place has them:
http://www.jawsgear.com/Ring_And_Pin...duct_info.html

MachinistMark

I'd prefer 3.90s or even 4.11s which 9bolt sells and is the only place I've seen with any gears lower than 3.73

Base91

iTrader: (1)

I think you can get the higher ratios for series 2 carriers just look for the "thick" ring gear. Usually has a T in the part number. But cost of 9-bolt parts may make it more cost effective to stick with 10-bolt.

RedLeader289

iTrader: (2)

Gotcha. I'm guessing you have overdrive (700R4)? That's the only thing that makes me stay at 3.27s, I have a TH350, with no OD I like to retain SOME mpgs on the interstate, haha.

MachinistMark

200c. The 3.90's I want because of the cam I want to run. Going to need a converter too, but that's a ways off. The car is just a toy, no where's near a daily driver

red rock

iTrader: (2)

What kind of horse power are you talking about? You need to get into some serious HP for a 3.90 or 4.11 rear end. If you have that kind of power, a 10 bolt isn't going to hold up at all. If i were you i would take the rear cover off and look at the ratio stamped on the ring gear. (might need a gear oil change anyway and look at the cones for wear) A 3 series is for a 3.08 and higher.

MachinistMark

Not according to the owner of the biggest supply company of 9 bolt parts.. Where is the 3 series 3.08 and higher info coming from?

I plan to be making some serious steam shortly, but need the ground work laid first.

I have a 9 bolt. Not a 10 bolt.

red rock

iTrader: (2)

I know you have a 9 bolt. I'm saying a 10 bolt is worse. Here is where i get it from. http://9bolt.com/gearsets.html You still need to know what you have. I also took a 3.08 carrier (3 series) and built a 3.70.

MachinistMark

That link says everything but 2.77's are 3 series.

red rock

iTrader: (2)

Well, yes it does. That's coming from the country that built the 9 bolt, Australia. I think I'm confused on what you were asking? If you want a 3.70 or 3.90 or 4.11 or whatever, you will need a 3 series carrier. You currently don't know what your gears are or what carrier you have. So if your gears are a 3.08, you carrier will be a 3 series and will be good for 3.90 gear set.

InfernalVortex

iTrader: (4)

I think the confusion is because red rock is assuming there are no gear ratios between 2.77 and 3.08 for the 9-bolt. So when he says 3.08 and higher is all 3-series, and you say no everything above 2.77 is 3-series... I think that's the disagreement.

I dont think there are any ratios between 2.77 and 3.08, certainly not any common in the states although from what i understand that axle (Spicer) is super common down under and are still made today.

red rock

iTrader: (2)

There is one gear 2.92 that is still a 3 series, but was never offered in a 3rd gen. I think the OP still needs to verify what gears he has in his car then determine the gear he would like. Depending on the HP a person wants to run has a factor in determining the gear and what rear end to run it in. The 9 bolt is very rebuildable and a good solid rear, but it does have it's limitations just as does the 10 bolt.

Base91

iTrader: (1)

Before you spend any money on gears have you checked the cones to make sure there is life left in them?

gt4373

If You Can Locate The Rear Axle ID Code,You Should Be Able To Find Out What Gear You Have.

MachinistMark

So if its a 3 series carrier the axle code would have a 3 stamped? What does the ab stand for?

scoflaw

iTrader: (2)

Rotate both rear wheels 1 full revolution and count how many times the driveshaft rotates. No need to take anything apart to tell what ratio you have.

gt4373

Those Numbers Are Used Just As An Example,Yours Would Be Different.