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#1 |
Active Member
Join Date: Mar 2004
Location: Virginia
Posts: 169
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Eaton Rearend
I just picked up a 72 K20 and it supposedly has an Eaton rearend (big and round). What does this mean? Pros/Cons? I have heard that this means I have very limited ring and pinion options. I would love to swap out what I have, (think they are 4.56) for some 3.73s or something so I can at least drive it on the highway. I am having a very hard time finding any info about these rearends. Any info is appreciated.
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71 Blazer CST 72 K20 Capt USAF |
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#2 |
Registered User
Join Date: Feb 2003
Location: The Rubber City
Posts: 5,498
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Re: Eaton Rearend
Try searching this site, especially the 4x4 page. You should find everything you need.
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1969 GMC K2500 ![]() 1996 Honda Accord 2007 Kawasaki KLR 650 |
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#3 |
Account Suspended
Join Date: Oct 2004
Posts: 1,276
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Re: Eaton Rearend
you can find a 4.10 rear center section and bolt her in. I don't believe there are any higher geared than that. Remember, it is a tuck axle.
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#4 |
Registered User
Join Date: Feb 2003
Location: The Rubber City
Posts: 5,498
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Re: Eaton Rearend
there is a 3.90 aftermarket gearset available.
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1969 GMC K2500 ![]() 1996 Honda Accord 2007 Kawasaki KLR 650 |
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#5 |
Active Member
Join Date: Mar 2004
Location: Virginia
Posts: 169
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Re: Eaton Rearend
I saw something about the 3.90 ring and pinion, but I can't find it for sale anywhere. The one place that did, had it listed as no longer being made. How would the 3.90 work with the front differential? Do they make a 3.90 for that too?
Maybe it's better to swap in a Dana 60?
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71 Blazer CST 72 K20 Capt USAF |
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#6 |
Senior Member
Join Date: Nov 2005
Location: northwestern wi
Posts: 2,111
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Re: Eaton Rearend
i'v been told that 14 boltff caierers will fit the eatons but you must use the 14 bolt axels which will need to be shortened an inch or inch and a half then some machining is require for outer axel bearings more info is avalibale on pirate 4x4 message board.
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common sense isn't so common anymore |
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#7 |
Special Order
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Location: Mt Airy, MD
Posts: 85,858
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Re: Eaton Rearend
4.10 to 3.90 ain`t worth it in my book.It`s a small difference.I`ve been driving trucks with HO52s for over 30 years on the hiway.I`d go with o/d to drop the rpms.
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"BUILDING A BETTER WAY TO SERVE THE USA"......67/72......"The New Breed" GMC '67 C1500 Wideside Super Custom SWB: 327/M22/3.42 posi.........."The '67" (project) GMC '72 K2500 Wideside Sierra Custom Camper: 350/TH350/4.10 Power-Lok..."The '72" (rolling) Tim "Don't call me a redneck. I'm a rough cut country gentleman" R.I.P. ~ East Side Low Life ~ El Jay ~ 72BLUZ ~ Fasteddie69 ~ Ron586 ~ 67ChevyRedneck ~ Grumpy Old Man ~ |
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#8 |
Active Member
Join Date: Mar 2004
Location: Virginia
Posts: 169
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Re: Eaton Rearend
ok, I think it is 4.56 right now. It's a 4x4 with a 350 SM465. Is overdrive even an option?
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71 Blazer CST 72 K20 Capt USAF |
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#9 |
Just hang'n around
Join Date: Nov 2005
Location: Camano Island WA
Posts: 248
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Re: Eaton Rearend
You can keep your same rearend and tranny and go with a GearVenders Over/Underdrive unit.
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Driving a '68 Chevy C20 and a '93 Astro Van. Lots and lots of mileage that I deduct each year. |
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#10 |
Account Suspended
Join Date: Oct 2004
Posts: 1,276
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Re: Eaton Rearend
bigger rubber!
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#11 |
Aluminum slot wheels rule...
Join Date: Jan 2006
Location: Maine
Posts: 6,212
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Re: Eaton Rearend
IIRC, Jim carters truck parts has the 3.90 gears, but they are a good chunk of change.
I'd probably go with a D60. Parts for them are common, and if you look around, I think you can find 3.21 and numerically lower ratio's. Last edited by JAKES 68GMC; 04-02-2006 at 09:13 PM. |
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#12 |
Active Member
Join Date: Mar 2004
Location: Virginia
Posts: 169
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Re: Eaton Rearend
You'd really go with a D60 over the 14 bolt? I have 8 lugs right now. Pros/con for D60 and 14 Bolt?
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71 Blazer CST 72 K20 Capt USAF |
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#13 |
Aluminum slot wheels rule...
Join Date: Jan 2006
Location: Maine
Posts: 6,212
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Re: Eaton Rearend
A Dana 60 is a 8-lug full-floater rear. I don't know much about the 14 bolt though.
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