what axles for a 3/4 ton - The 1947 - Present Chevrolet & GMC Truck Message Board Network

GreenMystChevy · 08-04-2003, 01:06 PM

I am getting ready to put this 8" lift on my '72 K-10 and with the tires I plan on running and towing a boat here and there, I want some bigger axles. So I am going to be looking for some 3/4 ton axles, hopefully out of a '72 so that they are the same year as my truck and I don't have to do as much fitting and linkage problems. I also don't want to have to remember all the different years I have on my truck.

My big question is: What axles am I looking for? I realize they are 8 lug, but what are they called and what are the ins and outs? I don't think I will be running into any problems when I bolt these suckers up... Thanks for the help guys.

wildwood · 08-04-2003, 03:10 PM

I think you'll have to change the whole rear end to go 3/4 ton. Look for a 14 bolt rear end. On the other hand, I don't think you'll have problems with the 1/2ton stuff if your tires aren't too big (35s or less). But that's just my opinion

**JIMs70GMC** · 08-05-2003, 05:41 AM

Well, the dana 60 and an corperate/eaton 10 bolt were the two axles found in the rear of 3/4 ton 4x4s. The corperate/eaton 10 bolt was not made past 72 and there fore parts available are mainly used and only one locker available the no-spin(detroit locker), the dana 60 on the other hand is still made and new parts are available. The front you are limited to the 8 lug dana44, you should try for a 73 to 78 model for the larger u-joints. The 8 lug 10 bolt front is also an option. The 14 bolt from a 3/4 ton would be the way to go as was said. Either way the should bolt up no problems (the one ton 14 bolt has a different spring perch spacing and they will have to be moved.

Bob Chayer · 08-10-2003, 09:13 AM

I just did this swap on my 1/2 ton '71 Suburban. I used a '72 3/4 ton donor truck with a Dana 44 upfront and an Eaton 10 bolt in the rear. The axles swaped no problem and took less than a weekend with some help from my buddies. The brake master needs to be used from the 3/4 ton and the rear rubber brake hose will need to be used also. The rear brake line will also need some modification as the rubber hoses are different lengths and they mount to the 1/2 ton and 3/4 ton in different ways. (The 1/2 ton mounts to the frame and the 3/4 has a bracket that brings the hose closer to the diff.) The 3/4 ton axle also uses 1/4" line all the way to the wheels. You need the rear drive shaft from the 3/4 ton and you will need to use the transfercase output yoke from the 3/4 ton as the u joints are larger. The front is all the same including the brake calipers which bolt right up. Steering is the same. Shocks are the same. This was a VERY easy swap. I have had no problems finding Eaton parts for the rear axle and it will without a doubt be able to tow any boat. The Eaton is MASSIVE! The only down side is the axles only come with 4.10 (as mine is) amd 4.56 gears. the 4.10s were in most V8 trucks and the 4.56s were in the 6cyl models. If you keep a stock tire your gear ratio will be off. I solved this problem with a larger tire (35")Hope this helps and let me know if you have any other questions. Good luck!

K5KRAZIE · 08-15-2003, 01:47 AM

A 14 bolt out of a 1 ton or van will "fit" your truck, as will the Eaton axle. You may have to get some shock mounts welded on to the 14 bolt but for your application I would recommend it. You can buy u-joints with an uneven cross to fit your driveshaft and the HD rear axle. However since your doing a 8" lift I would recommend to you that you have the new driveshaft built one of two ways, either with a bigger yolk on the lower end only or get the 3/4-1 ton yolk for the t-case and convert the whole shaft.
You can convert your existing front axle to 8-lug to match the rear very easily.
***my opinon and possibly only mine***
I'm having trouble with the means of which you think you need to do this swap. You will be towing a boat, cool. You will have a large lift on your truck with I imagine a max of 40" rubber, again cool. Will you be using the go pedal in large fuel consuming ways? Towing a large boat with very large tires is not a very good idea although it can be done. I would say that you would need to re gear your existing axles and be done with it.
***opinon over, thank you***

08-04-2003, 01:06 PM	#1
GreenMystChevy Registered User Join Date: Jan 2002 Location: Woodinville, WA Posts: 513	what axles for a 3/4 ton I am getting ready to put this 8" lift on my '72 K-10 and with the tires I plan on running and towing a boat here and there, I want some bigger axles. So I am going to be looking for some 3/4 ton axles, hopefully out of a '72 so that they are the same year as my truck and I don't have to do as much fitting and linkage problems. I also don't want to have to remember all the different years I have on my truck. My big question is: What axles am I looking for? I realize they are 8 lug, but what are they called and what are the ins and outs? I don't think I will be running into any problems when I bolt these suckers up... Thanks for the help guys. __________________ Jeremy '71 C-10 '72 GMC K2500 '72 Nova (Dad's) '70 Chevelle SS '55 Sedan Delivery Attempting to build up this here 4x4...make her real tall and purty...well, maybe just tall

08-04-2003, 03:10 PM	#2
wildwood Registered User Join Date: Jun 2003 Location: Calgary AB Posts: 110	I think you'll have to change the whole rear end to go 3/4 ton. Look for a 14 bolt rear end. On the other hand, I don't think you'll have problems with the 1/2ton stuff if your tires aren't too big (35s or less). But that's just my opinion __________________ You can't get out if ya don't get in

08-05-2003, 05:41 AM	#3
JIMs70GMC user # 2756 Join Date: Jun 2001 Location: Chesapeake, Virginia Posts: 4,612	Well, the dana 60 and an corperate/eaton 10 bolt were the two axles found in the rear of 3/4 ton 4x4s. The corperate/eaton 10 bolt was not made past 72 and there fore parts available are mainly used and only one locker available the no-spin(detroit locker), the dana 60 on the other hand is still made and new parts are available. The front you are limited to the 8 lug dana44, you should try for a 73 to 78 model for the larger u-joints. The 8 lug 10 bolt front is also an option. The 14 bolt from a 3/4 ton would be the way to go as was said. Either way the should bolt up no problems (the one ton 14 bolt has a different spring perch spacing and they will have to be moved. __________________ 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

08-10-2003, 09:13 AM	#4
Bob Chayer Registered User Join Date: Dec 2002 Location: Mid, NH Posts: 150	hopefully out of a '72 so that they are the same year as my truck and I don't have t I just did this swap on my 1/2 ton '71 Suburban. I used a '72 3/4 ton donor truck with a Dana 44 upfront and an Eaton 10 bolt in the rear. The axles swaped no problem and took less than a weekend with some help from my buddies. The brake master needs to be used from the 3/4 ton and the rear rubber brake hose will need to be used also. The rear brake line will also need some modification as the rubber hoses are different lengths and they mount to the 1/2 ton and 3/4 ton in different ways. (The 1/2 ton mounts to the frame and the 3/4 has a bracket that brings the hose closer to the diff.) The 3/4 ton axle also uses 1/4" line all the way to the wheels. You need the rear drive shaft from the 3/4 ton and you will need to use the transfercase output yoke from the 3/4 ton as the u joints are larger. The front is all the same including the brake calipers which bolt right up. Steering is the same. Shocks are the same. This was a VERY easy swap. I have had no problems finding Eaton parts for the rear axle and it will without a doubt be able to tow any boat. The Eaton is MASSIVE! The only down side is the axles only come with 4.10 (as mine is) amd 4.56 gears. the 4.10s were in most V8 trucks and the 4.56s were in the 6cyl models. If you keep a stock tire your gear ratio will be off. I solved this problem with a larger tire (35")Hope this helps and let me know if you have any other questions. Good luck! __________________ Bob Chayer 71 3/4 ton 4X4 Suburban

08-15-2003, 01:47 AM	#5
K5KRAZIE Registered User Join Date: Oct 2002 Location: Wa. State Posts: 352	A 14 bolt out of a 1 ton or van will "fit" your truck, as will the Eaton axle. You may have to get some shock mounts welded on to the 14 bolt but for your application I would recommend it. You can buy u-joints with an uneven cross to fit your driveshaft and the HD rear axle. However since your doing a 8" lift I would recommend to you that you have the new driveshaft built one of two ways, either with a bigger yolk on the lower end only or get the 3/4-1 ton yolk for the t-case and convert the whole shaft. You can convert your existing front axle to 8-lug to match the rear very easily. *my opinon and possibly only mine* I'm having trouble with the means of which you think you need to do this swap. You will be towing a boat, cool. You will have a large lift on your truck with I imagine a max of 40" rubber, again cool. Will you be using the go pedal in large fuel consuming ways? Towing a large boat with very large tires is not a very good idea although it can be done. I would say that you would need to re gear your existing axles and be done with it. *opinon over, thank you* __________________ TRUCKS '72 K5 '06 mega dually



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