rear end questions

[DukeGnarley]

ok so my currie 9" housing should be here tomorrow (HURRAY!!!) but i was looking at my current rear end tonight, and then a few questions suddenly dawned on me.....

Q1. Am i going to need to get different spring pads?(or whatever those things are called that the shocks and u-bolts bolt into.) If so, are there any that might come from a different car that will fit?

Q2. I ordered the axle housing and 31 spline axles without a 3rd member (trying to save some cash). Is anyone aware of a stock application that used a 9" 31 spline trac loc rear? I'm hopefully going to be hitting up a junk yard this saturday to get the rest of the stuff i need to finish the conversion.

Oh yeah...
Q3. When you switch to the 9", do you need to have the drive shaft shortened?

 

[LUCAFU1]

i highly doubt you will find a 31 spline third member since they only came in very few cars (cobra jets, boss).i have a few third members, all you would need a 31 spline diff. i have 3.10s and 4.11s

 

[danny clemens]

The best source for a trac lok with 31 spline axles is a pickup truck, van or a Bronco. You can tell by the axle code on the door if it is a trac loc or not. That is if is the original axle carrier.

 

[302 coupe]

yeah, alot of mid-late 70's trucks had 31 spline rears, some of which were trac-loks. Alot of 'em had good gear ratios too.

 

[DukeGnarley]

Thanks! does anyone know about the drive shaft or the spring things?

 

[danny clemens]

New spring plates and U-bolts are going to depend on if they put the smaller axle tubes on the end or not. If they did it right for your car it should have the small tubes and you can reuse your spring plates and U-bolts. If it has the larger tubes (there are different O D large tubes also) you'll have to get new U-bolts and spring plates. You can drill your old plates out to match the wider tubes though. I welded mine up and then drilled them so it wouldn't have an oval hole in it. I haven't got to the driveshaft part yet but it is my understanding that there are two different yoke lengths and the driveshaft has to be shortened for both. I'm going to try a short yoke first. There are people on here that have completed this mod so maybe they'll chime in and give you more info.

 

[DukeGnarley]

housing just showed up, and it's got the large OD tubes. but if there's space on the old plates for holes then there shouldn't be a problem. might as well weld on some tie down hooks while i'm at it.

 

[mikemustang289]

the larger bearing housings use different brakes.

You will need to shorten the driveshaft 1 inch or so.

Look on ebay for a center section.

 

[fastback brian]

You can have the large tube and small bearing 31 spline axles, thats what I have. You can keep your stock drive shaft if you use the short passenger car yoke, you will need to change the rear ujoint, it will now be the same as the front ujoint.
Spring plates from a 67-70 will work..NOT the ones for a stagger shock...

 

[DukeGnarley]

The ends i have are the Torino style big bearing ends. I also bought some baer brakes to match, so it should be ok. I'm just down to getting a 3rd member. Does anyone know how much better a detroit tru-trac is compared to the ford trac-lock? I know someone who can get me a good deal on one, so i'm a little tempted.

 

[Elroy]

Be aware that if you do find a 31 spline axle from a truck it "MAY" actually be a 9 3/8 NOT a 9. Check it out before you buy it

 

[danny clemens]

Be aware that if you do find a 31 spline axle from a truck it "MAY" actually be a 9 3/8 NOT a 9. Check it out before you buy it

I've looked at a lot of truck rears and only one had the 9 3/8. Most of the 9 3/8's that I have saw were in station wagons and big cars. I would make sure that it wasn't the wrong carrier though.