Upgrading from a 2.56 to a 3.08?

This just popped up locally http://sanantonio.craigslist.org/pts/3840012981.html

I'm very close to still buying that 95 Roady, if the transmission issues get sorted out, but one of the first mods I want to do is the rear axle. That 2.56 is stupid, car has no power and is not fun like my last one. Would the gears above work in my rear axle, and if so, what else should I change to do the swap?

Thanks again all,

-Mike

The plot thickens.   The man that I sold my OCC to has a '93 Roady wagon posi rear, and offered to make me a deal on it for the new '95 Roady if I get it.   He's checking the ratio and will get back to me later.
 
Anyone know what needs to be swapped to go from a LT1 rear to and TBI rear?   Is it a bolt-in swap??
 
-Mike

The 93 RMW rear with be 2.73, or 3.23 if it was a trailer pack car. Bolt in. Programming required.

jayoldschool wrote:

The 93 RMW rear with be 2.73, or 3.23 if it was a trailer pack car.  Bolt in.  Programming required.

Thanks Jay! He did say it came from a tow-pack and is a posi, so should be a 3.23. That ought to wake that wagon up a lot I'd think!

Do I just need to have it programmed to correct the speedo error?

-Mike

Yes, and shifting.

Thanks again!

Jay, do you know how to reprogram the computer in a 95?

Well, I stayed at a Holiday Inn Express last night...

81X11 wrote:

This just popped up locally  http://sanantonio.craigslist.org/pts/3840012981.html

I'm very close to still buying that 95 Roady, if the transmission issues get sorted out, but one of the first mods I want to do is the rear axle.   That 2.56 is stupid, car has no power and is not fun like my last one.   Would the gears above work in my rear axle, and if so, what else should I change to do the swap?

Thanks again all,

-Mike

Will they work? Mostly.

Should you do it? No.

Even if the ring & pinion were free, leave them. as you still would need a to procure a 3 series carrier and then pay someone to set the gear pattern.

And you still have to re-program the PCM.

Starting to think this is going to get expensive?

Go buy the rear you were offered, or make a trip to the JY and score a nice one that already has a decent ratio. Get another PCM while you're there.

Chris P (SWTSS) has done this on his RMW.

We pulled a 3.23 / posi rear out of a junked OCC and swapped it in w/o even bleeding the brakes.

First we removed the drums & axles, unbolted the backing plates and tied them out of the way.

Next we swapped the housings, attached the brake assemblies to the new rear, then slid the axles in and buttoned everything up.

Lastly, we had a spare PCM already pre-programmed by a friend waiting on deck, so when the work was done, it was exchanged and the car was all set to drive home.

- J

The wagons all came with 3 series carriers. If you get a complete rear, you can bolt it in, have the computer adjusted for gear ratio, and drive away. It is easier to bleed the brakes than change the axles.

If you are bolting it into a 91-93, you need the correct driven VSS gear for the gear ratio. The 3.23 with 225/75/15 tires uses a 42 tooth (green) gear. You may have to replace the VSS if you have one for 34-39 tooth gears (orange, light green, red, or white gears). In a 91-93 you do not have to reprogram the computer.

well,..... i,ve swapped in ring and pinions and carriers and shims from one housing to another more than once,.
you,d be surprised how close things are,.
It,s interesting in the real world just how far out of whack ring and pinions get after a few years,. but still work fine,..

I have witness's that will tell you that with the right programming and a well tuned up LT1,. you can fry a right rear tire with 2:56's and 255-50 17's on the lead weight impala ss rims,.

Quote :

The wagons all came with 3 series carriers

No, they didn't. 2.56 were 2 series carriers. Everything else (2.73 and above) were 3 series. Of course, if you are talking TBI only, there was no 2.56.

Thanks all for the comments. Good to know what I have to do to make this work.

-Mike