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Old 11-09-2004, 11:32 PM   #1
wolfthing2000
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Axle shafts and 3/4 & 1ton

I am in the process of finding a 3rd member 4;56 ratio for a 69 K 20 rear axle.. That is the corporate axle dropout style( Eaton?). I have been told to look out for the spline count for the axle shafts as they differ for 3/4 and 1 tons.. The guy told me to check hex size on the axle flange bolts:::::::::: 3/4 inch ( what I have on the K-20 which to my knowledge came with the truck from factory) indicates a 1 ton. In other words it takes a 3/4 socket or wrench to remove the bolts. But he says the 3/4 ton axle has 5/8 bolts and a different spline count????

What is there to this?? Any fact here or just backyard talk??

I will pull an axle before I head to the salvage yard to be sure.
Thanks,

Dave
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Old 11-09-2004, 11:43 PM   #2
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The spline count is the same. Not sure about the nut size.
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Old 11-10-2004, 01:07 PM   #3
wolfthing2000
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Does it matter what years?? ie: 52, 57,68 69, are all the same????
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Old 11-10-2004, 03:30 PM   #4
Fred T
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Different years have different axle lengths. There is also some variation on length between the 3/4 & 1 ton. If you have the standard 10 bolt, non-posi what you need is the pumpkin out of a 64-72 3/4 or 1 ton. There was not a ratio higher than 4.56 before '64. About all you will find for higher gears is the 4.10, and they are getting scarce. I have heard of one guy on the stovebolt board finding a 3.73 out of a blazer, but that's it.

If you want better gears, get a 14 bolt out of a later model truck and replace the entire differential. there are a lot of them with 3.73, some of the later models even had 3.42 gears.
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Last edited by Fred T; 11-11-2004 at 12:56 AM.
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Old 11-10-2004, 08:03 PM   #5
Stocker
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Fwiw,

My K20 axle bolts take a 3/4" socket. Stock (afaik) Eaton HO52 with 4.10s, coulda told you how many splines a couple weeks ago...
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Old 11-10-2004, 09:07 PM   #6
JIMs70GMC
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For some reason I'm thinking 17 splines.
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1970 K25, 8' stepside bed 350/465/205 44 up front, 60 in the rear 4.10s rolling on 33" Dunlop MTs
1986 K5, 350/465/208 Dana 60/14 bolt from a cucv 36" Super Swampers TSL/SX
1983 K20 w/ CUCV axles, 350/700R4/208 sitting on 37" Goodyears
1986 M1031 6.2 diesel, TH400/NP205 locker in the rear and a LS in the front, all stock for now.....
1986 K30, 350/400/205 dana 60 and 14 bolt. I kept the drivetrain. Body/bad and chassis are gone.
1981 K30, 350/465/205 dana 60 and dually 14 bolt. Has a G80, and a flat bed. Going to replace the flat bed.

1985 K20, 350/400/208 10 bolt and SF 14 bolt. I wonder where I can find some 1 tons. Hmmmmm
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Old 11-10-2004, 10:32 PM   #7
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17 it is.
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