70 3/4 ton coil spring rear - The 1947 - Present Chevrolet & GMC Truck Message Board Network

chevynut · 10-22-2002, 02:15 AM

Driving home today I spotted a 70 C20 in the back of a car lot. I had to stop and investigate. It had a coil spring that was not a Dana or a regulat 12 bolt. It had a round pumpkin. Anyone know what type of rear end this is? What gear ratio came as standard in 1970 3/4 with a 6cyl? Is the rear end worth anymore than a leaf spring Dana?

The truck was rusted to hell execpt the drivers front fender. I need this fender but the guy was asking $250 for the truck. I could probably get it for 100-150.

I am trying to decide if this truck (fender) is worth all the sh_t I will catch from the wife. If the rear has some worth maybe it come home with me...

Thanks, Mike

Longhorn Man · 10-23-2002, 12:21 AM

That is the EATON axle...also called the crop axle.
They were tough as nails, but the parts are getting hard to find, and the prices for the parts are getting kinda high.
Coil springs were the standard fair on 3/4 tons and 1/2 tons alike (Chevy...not GMC)
The coils woul ride better more likely than not.

**truckster** · 10-23-2002, 08:25 AM

The gear ratios in that one is likely a 4.11 or 4.57. Parts are next to impossible to find, unless you're willing to spend a bundle.

crew70 · 10-23-2002, 08:44 AM

eaton rear ends.... here we go again! lol

Big69C20 Toy · 10-23-2002, 10:38 AM

yep, eaton rear end. some actually had a factory posi unit didnt they andy? i not sure what the codes are but you could prolly find out. Super tough rears and some of the parts are able to swap with the 14 bolt FF from what i've read..

**COBALT** · 10-23-2002, 12:43 PM

Boy I love this debate.

HO52 or HO72 hybrid with Eaton carrier (don't call it an Eaton axle, please -- the carrier is the Eaton part, but the housing is made by someone else), but also known as a GM Corporate 10 bolt axle. It likely has either 4.10 or 4.56 gears. On the very rare occasion may have a 3.73, but I wouldn't bet on it. I've only seen one of those. Also may have an Eaton Posi unit in the carrier or a governor locker, but most likely has the ole' spider gears for that wonderful "one-wheel-wonder" kinda traction. It has a removable 3rd member (the front of the differential drops out).

longhornmail is right in the fact that they're tough, but only if the pinion and carrier bearings are in good shape. If not then kiss it goodbye. It will self-destruct quickly, and cost you a bundle if you want it fixed.

Here's why:

1. Bearing set (carrier + pinion) = $550
2. Detroit Locker for carrier (posi and spiders are no longer available unless used AND in good shape) = $550
3. New gear set (only 3.90s off the shelf new available) = $220
4. Labor (they're a *****) = $200

You're looking at around $1500 to rebuild it if it needs it. I would recomend swapping to something that has extra parts available. I screwed up and mentioned a 12 bolt earlier, but a lot of people have converted to '73 and up 14 bolt axles. In the mean time you can use it to practice on if you want to learn differentials. I had mine rebuilt because I knew squat about diffs. when I started and mine was in bad shape. One of the spiders had lost its bearing, and had frozen - welding itself to the carrier cross-member pin. The other spiders broke the teeth off if the frozen one and kept turning. The pumpkin had metal debris floating around in 30-year-old fluid. The carrier bearings pitted, and it started to self-destruct when I got it. It had sat in a field for 2 years. The truck would let out this humming noise above 50 mph that would vibrate the steering wheel.

I had 3.90s with a detroit locker and new bearings put in. The thing is solid for another 30 years, but I'm going to unload it for a new dana 60 axle with disk brakes with 3.73 when I do the frame-off. I already have a taker (jostrans68), so get in line if anyone wants it.

da-burb · 10-23-2002, 01:58 PM

Quote:

I would recomend taking it out and replacing it with a dana 60 or 12 bolt

I hope you mean the 14 bolt from 1973 and up.

**COBALT** · 10-23-2002, 03:35 PM

Yeah, sorry.

10-22-2002, 02:15 AM	#1
chevynut Registered User Join Date: Sep 2000 Location: Tampa, FL. USA Posts: 171	70 3/4 ton coil spring rear Driving home today I spotted a 70 C20 in the back of a car lot. I had to stop and investigate. It had a coil spring that was not a Dana or a regulat 12 bolt. It had a round pumpkin. Anyone know what type of rear end this is? What gear ratio came as standard in 1970 3/4 with a 6cyl? Is the rear end worth anymore than a leaf spring Dana? The truck was rusted to hell execpt the drivers front fender. I need this fender but the guy was asking $250 for the truck. I could probably get it for 100-150. I am trying to decide if this truck (fender) is worth all the sh_t I will catch from the wife. If the rear has some worth maybe it come home with me... Thanks, Mike __________________ Mike 1989 C1500 SWB Reg Cab 2003 Chevy Tahoe Z-71 70 Camaro RS/SS - 454

10-23-2002, 08:25 AM	#3
truckster Senior Member Join Date: Jan 2001 Location: Orem, Utah Posts: 7,832	The gear ratios in that one is likely a 4.11 or 4.57. Parts are next to impossible to find, unless you're willing to spend a bundle. __________________ I have sworn upon the altar of God, eternal hostility against every form of tyranny over the mind of man. - Thomas Jefferson

10-23-2002, 08:44 AM	#4
crew70 Registered User Join Date: Jan 2002 Location: shafer,mn,usa Posts: 316	eaton rear ends.... here we go again! lol __________________ 70 chevy 3/4 ton 4x4 402ci crewcab 3/4ton 94 gmc 1 ton dually crewcab 454ci 99 suburban 5.7 2001 500cc ski-doo mxz 95 500cc ski doo fan 650 bombardiar 4 wheeler

10-23-2002, 10:38 AM	#5
Big69C20 Toy Livin' it up. Join Date: Nov 2001 Location: Richland, MI Posts: 2,212	yep, eaton rear end. some actually had a factory posi unit didnt they andy? i not sure what the codes are but you could prolly find out. Super tough rears and some of the parts are able to swap with the 14 bolt FF from what i've read.. __________________ -Greg; Sold the 69 C20. It's off to a better home with more love! Now onto the 86 CUCV M1009; K5 blazer with 6.2L diesel, corp 10 bolt axles, Detroit locker in the rear, trutrac front, 3.73 gears, 35" tires.

10-23-2002, 12:43 PM	#6
COBALT Senior Member Join Date: Sep 2001 Location: Seattle, WA, USA Posts: 5,817	Boy I love this debate. HO52 or HO72 hybrid with Eaton carrier (don't call it an Eaton axle, please -- the carrier is the Eaton part, but the housing is made by someone else), but also known as a GM Corporate 10 bolt axle. It likely has either 4.10 or 4.56 gears. On the very rare occasion may have a 3.73, but I wouldn't bet on it. I've only seen one of those. Also may have an Eaton Posi unit in the carrier or a governor locker, but most likely has the ole' spider gears for that wonderful "one-wheel-wonder" kinda traction. It has a removable 3rd member (the front of the differential drops out). longhornmail is right in the fact that they're tough, but only if the pinion and carrier bearings are in good shape. If not then kiss it goodbye. It will self-destruct quickly, and cost you a bundle if you want it fixed. Here's why: 1. Bearing set (carrier + pinion) = $550 2. Detroit Locker for carrier (posi and spiders are no longer available unless used AND in good shape) = $550 3. New gear set (only 3.90s off the shelf new available) = $220 4. Labor (they're a ***) = $200 You're looking at around $1500 to rebuild it if it needs it. I would recomend swapping to something that has extra parts available. I screwed up and mentioned a 12 bolt earlier, but a lot of people have converted to '73 and up 14 bolt axles. In the mean time you can use it to practice on if you want to learn differentials. I had mine rebuilt because I knew squat about diffs. when I started and mine was in bad shape. One of the spiders had lost its bearing, and had frozen - welding itself to the carrier cross-member pin. The other spiders broke the teeth off if the frozen one and kept turning. The pumpkin had metal debris floating around in 30-year-old fluid. The carrier bearings pitted, and it started to self-destruct when I got it. It had sat in a field for 2 years. The truck would let out this humming noise above 50 mph that would vibrate the steering wheel. I had 3.90s with a detroit locker and new bearings put in. The thing is solid for another 30 years, but I'm going to unload it for a new dana 60 axle with disk brakes with 3.73 when I do the frame-off. I already have a taker (jostrans68*), so get in line if anyone wants it. __________________ '69 3/4 ton C20 2wd-350ci/TH400 '69 3/4 ton Custom 20 2wd-350ci/4sp Manual '99 2wd 5.7 Chevy Tahoe Seattle, WA. Last edited by COBALT; 10-23-2002 at 03:56 PM.*

10-23-2002, 12:21 AM	#2
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	That is the EATON axle...also called the crop axle. They were tough as nails, but the parts are getting hard to find, and the prices for the parts are getting kinda high. Coil springs were the standard fair on 3/4 tons and 1/2 tons alike (Chevy...not GMC) The coils woul ride better more likely than not.

10-23-2002, 03:35 PM	#8
COBALT Senior Member Join Date: Sep 2001 Location: Seattle, WA, USA Posts: 5,817	Yeah, sorry. __________________ '69 3/4 ton C20 2wd-350ci/TH400 '69 3/4 ton Custom 20 2wd-350ci/4sp Manual '99 2wd 5.7 Chevy Tahoe Seattle, WA. Last edited by COBALT; 10-23-2002 at 03:50 PM.



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