another axle swap question - The 1947 - Present Chevrolet & GMC Truck Message Board Network

70Chevy4x4Nut · 09-27-2003, 10:13 PM

I'm working on a 70 4x4 1/2 ton pickup. I currently have 3.07 gears, open diffs. I know where there is a 77 3/4 ton chevy to buy parts off of. Does anyone know if these axles will bolt right up to my truck? I am assuming that the 77 has pretty low gears and maybe limited slip at least. I will have to convert to 8 lug, but thats ok. Just need to know if there are any other mods to make besides the driveshaft. Will all my old leaf springs, ubolts ect fit?

Thanks

70Chevy4x4Nut · 09-27-2003, 10:33 PM

In case you are wondering, the 3/4 ton donor truck is a 4x4. I want to swap both front and back axles at the same time. I think the truck has a TH400 with a NP203.

**JIMs70GMC** · 09-27-2003, 11:06 PM

The axles will bolt in. Will need new brake hoses, you can get hybrid u-joints, not sure about driveshaft length. Get the 3/4 ton drive shafts also, not sure if they will need to be shortened/lengthed or what but with both front and both rear driveshafts a shop could combine to get what you need.

GreenMystChevy · 09-29-2003, 11:22 AM

Doesn't he have to relocate the spring perches to match and what about ebrake cables and regular brake lines. I myself just purchased some 3/4 ton axles from a '75 chev and am just waiting for the time to do some more investigation.

**JIMs70GMC** · 09-29-2003, 11:51 AM

I thought the 3/4 ton 14 bolts had the perches in the right spot and 1 ton 14 bolts were different? Forgot about the e-brake, probably need to take the cables off of the donor also.

HeavyK20 · 09-29-2003, 12:51 PM

I think you will need to move the perches. Measure the center to center spring width on the '70 and compare it to the '77, I think there will be about a 2" difference.

GreenMystChevy · 09-29-2003, 01:44 PM

Ahh, what's 2" among friends. Just tighten it down real good, should work just fine. Just try not to drive wheel it too hard, turn it too sharp, drive it straight, etc. Heck, if you don't drive it at all you might not have to move the perches and it will be just fine!

P.S. I hope you caught the sarcasm!

LeRoy · 10-04-2003, 10:04 PM

When you snag the axles take the brakelines also. It'll be alot easy if you have both ends to get a set already made. Napa has a big book with lot's of pictures to compare. Trust me it's a pain with no reference to start with. Also you'll need to relocate one of the rear shock mounts. Pretty easy and well worth it swap. And yes take the drivelines. You'll be able to use your own front driveline but snag the rear. Those hybrid u-joints are more money and getting the donor driveline shortened is fairly cheap. It'll be huge in diameter compared to your stock driveline and you might have to move your mufflers over a tad to clear

09-27-2003, 10:13 PM	#1
70Chevy4x4Nut Registered User Join Date: Dec 2002 Location: TX Posts: 311	another axle swap question I'm working on a 70 4x4 1/2 ton pickup. I currently have 3.07 gears, open diffs. I know where there is a 77 3/4 ton chevy to buy parts off of. Does anyone know if these axles will bolt right up to my truck? I am assuming that the 77 has pretty low gears and maybe limited slip at least. I will have to convert to 8 lug, but thats ok. Just need to know if there are any other mods to make besides the driveshaft. Will all my old leaf springs, ubolts ect fit? Thanks

09-27-2003, 11:06 PM	#3
JIMs70GMC user # 2756 Join Date: Jun 2001 Location: Chesapeake, Virginia Posts: 4,612	The axles will bolt in. Will need new brake hoses, you can get hybrid u-joints, not sure about driveshaft length. Get the 3/4 ton drive shafts also, not sure if they will need to be shortened/lengthed or what but with both front and both rear driveshafts a shop could combine to get what you need. __________________ 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

09-29-2003, 11:22 AM	#4
GreenMystChevy Registered User Join Date: Jan 2002 Location: Woodinville, WA Posts: 513	Doesn't he have to relocate the spring perches to match and what about ebrake cables and regular brake lines. I myself just purchased some 3/4 ton axles from a '75 chev and am just waiting for the time to do some more investigation. __________________ 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

09-29-2003, 11:51 AM	#5
JIMs70GMC user # 2756 Join Date: Jun 2001 Location: Chesapeake, Virginia Posts: 4,612	I thought the 3/4 ton 14 bolts had the perches in the right spot and 1 ton 14 bolts were different? Forgot about the e-brake, probably need to take the cables off of the donor also. __________________ 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

09-29-2003, 12:51 PM	#6
HeavyK20 Registered User Join Date: Dec 2001 Location: New Richmond, WI Posts: 547	I think you will need to move the perches. Measure the center to center spring width on the '70 and compare it to the '77, I think there will be about a 2" difference. __________________ Eric 1969 K20, 465/205 package

09-27-2003, 10:33 PM	#2
70Chevy4x4Nut Registered User Join Date: Dec 2002 Location: TX Posts: 311	In case you are wondering, the 3/4 ton donor truck is a 4x4. I want to swap both front and back axles at the same time. I think the truck has a TH400 with a NP203.

09-29-2003, 01:44 PM	#7
GreenMystChevy Registered User Join Date: Jan 2002 Location: Woodinville, WA Posts: 513	Ahh, what's 2" among friends. Just tighten it down real good, should work just fine. Just try not to drive wheel it too hard, turn it too sharp, drive it straight, etc. Heck, if you don't drive it at all you might not have to move the perches and it will be just fine! P.S. I hope you caught the sarcasm! __________________ 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

10-04-2003, 10:04 PM	#8
LeRoy Registered truck nut Join Date: Dec 1999 Location: Mt. Vernon, Washington, USA Posts: 1,584	When you snag the axles take the brakelines also. It'll be alot easy if you have both ends to get a set already made. Napa has a big book with lot's of pictures to compare. Trust me it's a pain with no reference to start with. Also you'll need to relocate one of the rear shock mounts. Pretty easy and well worth it swap. And yes take the drivelines. You'll be able to use your own front driveline but snag the rear. Those hybrid u-joints are more money and getting the donor driveline shortened is fairly cheap. It'll be huge in diameter compared to your stock driveline and you might have to move your mufflers over a tad to clear __________________ MOUNT VERNON, WASH. STATE Need a part? Just PM me



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