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Old 12-18-2012, 12:19 PM   #1 (permalink)
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Default 2.79 to 3.55 swap

Hey all, besides going to a junk yard and whatnot and ripping the rear out of an old Ford (that sort of place has a surprisingly limited selection around here) what do I need to buy to change a 2.79 to a 3.55? What's my other options than going junkyard diving (not that I mind it, but again we just don't have almost anything here).
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Old 12-18-2012, 12:24 PM   #2 (permalink)
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When you come down I-81 thru Virginia (if still coming this way for xmas)- give Chris Stage a call. I was there a few weeks ago and he had a number of orig rears to choose from. He is not far off the highway. Not sure what ratios, but nice person to deal with.
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Old 12-18-2012, 12:28 PM   #3 (permalink)
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When you come down I-81 thru Virginia (if still coming this way for xmas)- give Chris Stage a call. I was there a few weeks ago and he had a number of orig rears to choose from. He is not far off the highway. Not sure what ratios, but nice person to deal with.




I'll give him a call now and see what he has.


Failing that, what would I need to buy and where can I get it?



For the record I'm not the one doing the swap, my buddy is. I have no intentions of doing anything with gears and transmissions myself.
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"Natalie", '66 Coupe, aka "Jinx", "Jinxie Natalie" (everything goes wrong..)
289, Holley Carb, Edelbrock Intake/Water Pump, Northern Rad
3.55 with Posi, Zoom Clutch
Next On the Agenda:
Interior - Soundproof, new carpet, tilt column (in progress), new steering wheel, seat extenders, Motolita MK3 (in progress)
Exterior/Body/Performance:T5 (In progress) weatherstripping, power steering (in progress)
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Old 12-18-2012, 12:42 PM   #4 (permalink)
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If you get a complete rear- its a bolt in deal. If you want to change the gear itself- you need the ring/pinion and someone who knows how to set that up (I do not- and from what I am told- guessing at it, or learning as you go will destroy the rear end very quickly) The axle/pinion bearings/seals is easy, couple bolts/seal puller and should be pretty easy. Now where to buy 8in gears- not sure- I have a 9 so maybe someone else will chip in- I know wareagle is in need of some gearing as well. Seems the 8 in is harder to find replacment gears
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Old 12-18-2012, 12:56 PM   #5 (permalink)
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I think you'll have to buy either a new or re-built center section. I bought a lightly used eaton tru trac with 3.55 gears from a member here. You probably wouldn't find what your looking for in any junkyard because the 2.79 was the standard in most mustangs and the rest have long been picked over. Re-built is $800/ $900 and a new one runs around $1100- used just doesn't come up very often and you have to know (trust) who your getting it from. You could also purchase the items seperately and have a local shop set it up but I don't think you'll save much for your efforts. I'm assuming that you want to change to a LSD as well. When I did mine I also changed the rear wheel bearings as you have it all apart and there not to expensive to change. John
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Old 12-18-2012, 01:02 PM   #6 (permalink)
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I think you'll have to buy either a new or re-built center section. I bought a lightly used eaton tru trac with 3.55 gears from a member here. You probably wouldn't find what your looking for in any junkyard because the 2.79 was the standard in most mustangs and the rest have long been picked over. Re-built is $800/ $900 and a new one runs around $1100- used just doesn't come up very often and you have to know (trust) who your getting it from. You could also purchase the items seperately and have a local shop set it up but I don't think you'll save much for your efforts. I'm assuming that you want to change to a LSD as well. When I did mine I also changed the rear wheel bearings as you have it all apart and there not to expensive to change. John


Woo I had no idea it was going to be a 1000 dollar deal. Can I not just get a ring and pinion set for like 200-300 bucks and hand it over to him?
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"Natalie", '66 Coupe, aka "Jinx", "Jinxie Natalie" (everything goes wrong..)
289, Holley Carb, Edelbrock Intake/Water Pump, Northern Rad
3.55 with Posi, Zoom Clutch
Next On the Agenda:
Interior - Soundproof, new carpet, tilt column (in progress), new steering wheel, seat extenders, Motolita MK3 (in progress)
Exterior/Body/Performance:T5 (In progress) weatherstripping, power steering (in progress)
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Old 12-18-2012, 01:02 PM   #7 (permalink)
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It's very easy to find all the parts you need for an 8". I rebuilt mine entirely a few months ago and recommend Randy's Ring & Pinion if you need a good place to go to get parts.

At a minimum, you will need a pinion crush sleeve, 3rd member/housing gasket, gaskets for the housing ends where the axles go in, gasket sealer, and gear lube. You'll also need a shim kit for setting the pinion depth and gear marking compound for checking the gears.

Other parts you might need would be pinion bearings, carrier bearings, and axle bearings (depending on their current condition). The axle and carrier bearings are pressed on, so you will need a press to install them. The axle bearings can be cut off if you don't have the special tool for pulling the axle bearings (they are a real pain in the butt to get off). The axle bearings are sealed bearings and usually hold up well over time.

You can get all the internal parts in an overhaul kit. It won't come with axle bearings or the gaskets for the housing ends, but it will have everything else you need.


Yo
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Old 12-18-2012, 01:06 PM   #8 (permalink)
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It's very easy to find all the parts you need for an 8". I rebuilt mine entirely a few months ago and recommend Randy's Ring & Pinion if you need a good place to go to get parts.

At a minimum, you will need a pinion crush sleeve, 3rd member/housing gasket, gaskets for the housing ends where the axles go in, gasket sealer, and gear lube. You'll also need a shim kit for setting the pinion depth and gear marking compound for checking the gears.

Other parts you might need would be pinion bearings, carrier bearings, and axle bearings (depending on their current condition). The axle and carrier bearings are pressed on, so you will need a press to install them. The axle bearings can be cut off if you don't have the special tool for pulling the axle bearings (they are a real pain in the butt to get off). The axle bearings are sealed bearings and usually hold up well over time.

You can get all the internal parts in an overhaul kit. It won't come with axle bearings or the gaskets for the housing ends, but it will have everything else you need.


Yo


Thanks for the thorough answer. For clarification though I have absolutely no intention of doing this myself, my buddy who has been working on and customizing mustangs for the better part of 40 years will be doing so.

What I'm trying to figure out is which parts I need to buy, and then hand over to him.
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"Natalie", '66 Coupe, aka "Jinx", "Jinxie Natalie" (everything goes wrong..)
289, Holley Carb, Edelbrock Intake/Water Pump, Northern Rad
3.55 with Posi, Zoom Clutch
Next On the Agenda:
Interior - Soundproof, new carpet, tilt column (in progress), new steering wheel, seat extenders, Motolita MK3 (in progress)
Exterior/Body/Performance:T5 (In progress) weatherstripping, power steering (in progress)
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Old 12-18-2012, 04:16 PM   #9 (permalink)
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Are you wanting to go with a posi? If not just order the gears and have your friend set them up if he knows how. And to follow up Did you figure out what was going on with your motor? maybe you posted it and i didn't see it.
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Old 12-18-2012, 04:43 PM   #10 (permalink)
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there was a guy selling used pumpkins on ebay for a reasonable amount
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Old 12-18-2012, 06:33 PM   #11 (permalink)
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PM sent back to you---
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Old 12-18-2012, 06:39 PM   #12 (permalink)
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Quote:
Originally Posted by md02geist View Post
Thanks for the thorough answer. For clarification though I have absolutely no intention of doing this myself, my buddy who has been working on and customizing mustangs for the better part of 40 years will be doing so.

What I'm trying to figure out is which parts I need to buy, and then hand over to him.
If all the bearings are good, at a bare minimum you will need:
-Ring & pinion set
-Pinion shim set
-Pinion crush sleeve
-Gaskets
-Axle seals & pinion seal (good idea to change out)
-Pinion support o-ring
-Gear marking compound
-Pinion nut (the old one will work, but it's always recommended to install a new one)

A lot of times you can get all these parts in a kit that is tailored specifically for gear changes. Here's an example of what would work for you:
Ford Mustang Rear Differentials Ford 8" Mini-Kits

Edit: You'll also need the gaskets since they don't appear to be included in the kit listed above.
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T56 6-speed
Rod & Custom Motorsports IFS
TCP subframe connectors
Vintage Air Heat & AC

'99 Black Cobra - Daily driver
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Last edited by Greg'66 5.0; 12-18-2012 at 06:43 PM.
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Old 12-18-2012, 06:40 PM   #13 (permalink)
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Nice, so a 40-60 dollar kit and the ring and pinion itself will be about 150-250 depending on what brand I go. So we're talking like 300 plus labor.
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"Natalie", '66 Coupe, aka "Jinx", "Jinxie Natalie" (everything goes wrong..)
289, Holley Carb, Edelbrock Intake/Water Pump, Northern Rad
3.55 with Posi, Zoom Clutch
Next On the Agenda:
Interior - Soundproof, new carpet, tilt column (in progress), new steering wheel, seat extenders, Motolita MK3 (in progress)
Exterior/Body/Performance:T5 (In progress) weatherstripping, power steering (in progress)
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Old 12-18-2012, 06:42 PM   #14 (permalink)
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Nice, so a 40-60 dollar kit and the ring and pinion itself will be about 150-250 depending on what brand I go. So we're talking like 300 plus labor.
Assuming all of the internal parts are good, then yes that's about right.
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Modifications:
5.0 EFI conversion
TwEECer EFI tuning
T56 6-speed
Rod & Custom Motorsports IFS
TCP subframe connectors
Vintage Air Heat & AC

'99 Black Cobra - Daily driver
http://i887.photobucket.com/albums/a...psdd2caa40.jpg
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Old 12-18-2012, 06:46 PM   #15 (permalink)
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Thats a good price on that 8'' install kit. With the 3.55 Summit gears your at $199.00 or so plus shipping.
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