robguitargod1

iTrader: (4)

Besides the Currie torque arm adapter, what else do I need? If I use ladder bars where can I get them and where do they mount? (this rear was used with them)

Will my stock shaft mount to the 9" yoke?

Any recommendations/suggestions would be much appreciated seeing how this is the first time I'll be installing this rear in this type of car. Thanks!

robguitargod1

iTrader: (4)

robguitargod1

iTrader: (4)

Some questions for you guys. The rear has a spool, but I 'd still like to drive it on the street and get a taller gear in there. Rear ends are the one thing I've never dug into, so what will I need to upgrade the gears and throw in a posi? Thanks!

AlkyIROC

I wouldn't recommend a spool on the street. You're better off with a good posi.

Ladder bars can be done but it's not a simple or easy task. The first 9" I put under my car had ladder bars. I installed a crossmember between my custom built SFC to attach the ladder bar to. I had to section the floor under the rear seat for the ladder bars to pass through.

Looking at that diff, it doesn't look like it was ever installing in a third gen unless they did a real good job grinding off the old ladder bar mounts. There's no torque arm mount and there's no ladder bar mounts welded to the axle tubes. It's possible it was used with something like the traction action lift bars. They replace the LCA and act like a very short ladder bar. Although they work, they are not a very good idea.

Your GM u-joint will not bolt up to the Ford yoke. You'll need a conversion u-joint. The GM end is called a 3G. The Ford yoke will be a 1310 or 1330. The easiest way it to take the yoke to your local auro parts store and tell them you need a conversion u-joint that will go from a 3G and needs to fit the yoke.

Unbolt and pull the axles. Pull the center section out to see exactly what's inside. Maybe it does have a posi and you'll be able to find out what gear ratio it is also. What size socket do you need to pull the axles?

This is what my old diff looked like with ladder bars.

robguitargod1

iTrader: (4)

Stephen, you're awesome man and thanks! I saw the Currie torque arm adapter, which I'll have to pick up. The U joint thing is good to know, but do you know if the people at the part store will look at me like I'm crazy? I can't stand when the people there have no clue what you're talking about!!

I've never disassembled a rear before, so I'll be taking plenty of pics. On the plus side, the brakes are brand new and never used.

Does anyone else besides Curry make the torque arm adapter? Where's a good place to pick up gears and a posi for it? Any other tricks of the trade with regards to a 9" in a third gen? Thanks man!

Pew

yeah a spool isent the best thing on the street i have one in mine and trust me you'll like a good posi alot better.I don't regret it but mine sees the track most of the time and the road maybe once every two months

AlkyIROC

Without knowing a lot about that diff, it's hard to make suggestions.

You should pull the axles to pull the center section to see what's inside. It will also help to know the axle spline count. Common Ford axles are 28 and 31 spline and even with aftermarket axles, I wouldn't recommend 28 spline.

Is the bolt pattern Ford or GM. If it has Ford brakes, I'd assume it's a Ford 5 on 4-1/2 instead of the Chev 5 on 4-3/4. That means you need Ford rims or rims with a dual bolt pattern such as Weld Draglite. Your Chev rims won't fit if it's a Ford bolt pattern.

Currie is the only company that sells the torque arm mount bracket for a 9". It's around $150 and requires very good welding (220v) to make sure there's good metal penetration.

When I installed that 9" I left the LCA attached to keep the diff positioned. Once I had the ladder bars welded up, the LCA were removed. You still need the panhard bar or a diagonal link to keep the diff centered. If you plan on using the Currie TA mount bracket, you won't have that problem.

Any good parts store will have a section in the u-joint catalog showing conversion u-joints. If they have exactly what you need in stock is another story but conversion u-joints are common. Trouble is, sometimes the conversion you want isn't available. I bought 3 different u-joints to make one conversion u-joint once by mix and matching the parts.

Gears and posi for a 9" are everywhere. Ebay is a good source. You can pull them out of your local junkyard also. Many Ford vehicles had a 9". I managed to pull a 4.10 31 spline posi out of an old Bronco for $100. Unlike GM, the carrier (spool, posi etc) in a Ford is only one series. You can put 2.50 or 6.50 gears on the same carrier. Before you buy a posi, you'll need to know the axle spline count first. If you have 31 spline axles, you can't use a posi for 28 spline.

Your brake lines are going to require some adapting. Those Ford wheel cylinders will use standard double flare fittings. They'll join to a flex hose adapter but the flex hose won't easily connect to the GM brake line because it will probably be the metric bubble flare.

robguitargod1

iTrader: (4)

So how can I tell if it's a ford or GM? I noticed about the 28 and 31 spline axles, but I'm hoping it's a Ford? I didn't know GM made a 9" if that's what you're saying!?

What if my GM wheels fit? Does that mean it could be a Ford rear end and someone put GM axles in it?! (do those even exist?) Sorry to be so clueless about this, and thanks for the priceless pointers! It's my first experience with this combo.

I do have a great welder too. It's a Miller millermatic DVI.

One more thing.............whats LCA mean man!!! Thanks again

EvilCartman

iTrader: (1)

Just for reference, here's my Currie 9" housing. The torque arm adapter needs a couple of beefy tubes welded onto the housing with some big bolts.

robguitargod1

iTrader: (4)

Wow awesome housing!!! So what's the little port on the right of the diff? Mine has one too. Breather? And how do you fill the housing with fluid?

89ROC-Z

iTrader: (7)

lca = lower control arm

and btw, do you have your welder in your office?!?!

robguitargod1

iTrader: (4)

LOL! No man, it was in my apartment...............along with my air compressor, torch, and tool chest!! had no place to put it until I finally rented a garage! Now things are all good.

AlkyIROC

The reason I mentioned Ford and Chev bolt patterns is because we know little about the diff. A Ford diff never came in a GM car. It's obvious from the mount brackets that your diff will fit into a third gen however there's no torque arm bracket so exactly what diff is it? Is it an aftermarket third gen diff that never had the torque arm bracket installed or is it a junkyard diff that someone converted to fit under a third gen like what I did to mine?

Either way, you need to know what brakes are on the car. It's very easy to install Ford brakes onto a Ford diff. If you have Chev bolt pattern axles, a Ford drum won't fit unless the holes are redrilled to the Chev pattern. You can't put GM axles into a Ford but you can get the Ford axles drilled to a GM bolt pattern. The aftermarket, direct bolt in 9" diff for a third gen has housing ends that allow you to use your GM brakes without having to do a lot of conversions.

My diff uses Ford brakes because it was the easiest way to install brakes. My rear rims use the Ford bolt pattern.

Measure across 2 wheel studs skipping one. Go from the outer edge of the first stud to the middle of the other stud. It will either be 4-1/2" or 4-3/4".



LCA = Lower control arms
LCARB = Lower control arm relocation brackets
SFC = Sub frame connectors

You'll see those terms used a lot on TGO.

robguitargod1

iTrader: (4)

I just measured 4-1/2 on the bolts and found the Ford logo, so yes it's a ford converted. I believe the guy I bout it from said it was used with the traction action lift bars you mentioned.

So the only thing I need are, Ford bolt pattern wheels, TA conversion bracket, and some way to connect to the brakes. Speaking of which, how should I go about doing that!? How can I connect my existing lines to the Ford wheel cylinders? Suggestions?

robguitargod1

iTrader: (4)

So I took apart the 9" tonight and discovered:

28 spline axles:
39 ring teeth, 13 pinion teeth
spool gear
missing a axle retaining bolt
brand new brakes

For $500 it's ready to run. Maybe not ideal, but it could be run as it is right now (adding the missing bolt of course). To make it perfect I'll put taller gears in it, and maybe a posi depending on how much I take it on the street. Suggestions? Comments? Thanks guys!

robguitargod1

iTrader: (4)

delete

robguitargod1

iTrader: (4)

AlkyIROC

That doesn't look like any of my spools. I have a steel Strange spool and some brand aluminum spool. My steel spool doesn't look anything like yours. Are you sure it's not an open carrier with a mini spool in it? That's what it looks like to me.

Retaining bolt is easy, go find one in a junkyard.

39:13 gears means 3.00:1 gear ratio. Not a performance ratio at all. As I've already mentioned, you can put any gear ratio you want on the carrier. Even factory 3.50 gears would be better.

Hard to give a good opinion. You want to upgrade to a posi for the street. Although I wouldn't recommend 28 spline axles, you're probably not in the power levels where you'll hurt them. The cheapest upgrade will be to buy a 28 spline posi, install it and go have fun. Measure the OD of the side bearing races. They're probably 2.891" which is the smallest bearings found in the majority of all factory cases. You'll need to know that when ordering a posi.

Although buying a 31 spline posi would be a better option, it also means needing to buy new 31 spline axles then your "deal" doesn't become much of a deal.

The bottom bolt under the pinion. Did you need to use a wrench to remove it or would a socket fit?

What's the casting numbers on the inside of the case? I can't read them in the picture.

robguitargod1

iTrader: (4)

What does open carrier with a mini spool mean?

Isn't a posi around $400-$500? That would suck to have to buy one

I'll just stick with the 28 spline axles because I'm probably only putting a little over 400hp to the wheels.

What do I need to measure? The outside diameter of what?

I used a socket and impact to remove the bottom bolt, so what does that tell you?

Where's the casting number? On the 3rd member or housing?

Stephen, can't thank you enough!

Robert

big gear head

I hate to hurt your feelings, but that is not a 9 inch. It's an 8 inch Ford.

robguitargod1

iTrader: (4)

Really? How can you tell?

robguitargod1

iTrader: (4)

Good call man, it does look like an 8". So does that mean I should sell it, or put a taller gear in it and use it anyway?

big gear head

I've been building rear ends for about 27 years. I've built about all of them. I can recognize a 8 inch when I see it. The 8 inch is a little stronger than the 7.5 that you probably have now, but I wouldn't go to the trouble of fabricating all of the parts needed to put it in the Camaro for the slight increase in strength. I'd look for something else.

robguitargod1

iTrader: (4)

but it's already ready to go into my camaro.

big gear head

If it's ready then use it. When you buy parts for it be sure to get parts for the 8 inch. The 28 spline axles were the largest available in the 8 inch, and are the same size as the 28 spline axles in the 7.5 10 bolt.

robguitargod1

iTrader: (4)

Could you give me a rough estimate of what the 8" can handle? I 'll probably be making 500hp on nitrous max. thanks

Rob

big gear head

Ford used the 8 inch in small block cars that didn't have a lot of power and some 390 cars with automatic transmissions. The '67 Fairlane GTA was the most powerful car that I know of that used the 8 inch rear end. This car was rated at 335 HP with an automatic transmission. Many street rods use this rear end, but they are light weight cars. You might get away with this with the power that you are making, but the small 28 spline axles are going to be stressed. If you only use street tires and keep wheel hop under controll then it will probably work all right. The good thing about this rear end is that it has press on axle bearings and no c clips on the axles.

robguitargod1

iTrader: (4)

Thanks man, you guys have been a ton of help!

Rob

AlkyIROC

If you can use a socket to remove "all" the center section bolts, it's an 8". A 9" center section needs a wrench to remove the bottom bolts.

Sorry to say this but like already mentioned above, you have an 8". The pictures were not good enough to allow me to make the call the first time. that's why I had to ask about the tools used.

robguitargod1

iTrader: (4)

So will the Currie TA adapter work with the 8" I have as well?

big gear head

The 8 inch housing is a little smaller. It might work, but it will probably need some modifications.

robguitargod1

iTrader: (4)

I emailed Currie about it so we'll see. Thanks

basiccamaro

EvilCartman, thanks for posting the first good picture I've ever seen of a 9" Ford diff with the torque arm adapter bracket on it! Now I'm tempting fate, but you don't have a good picture of the bracket hooked up to the torque arm installed in a car do you? Thanks!