Help with GMC rear axle decoding - The 1947 - Present Chevrolet & GMC Truck Message Board Network

RicksTrucks · 06-27-2005, 09:49 PM

I have a 71 3/4 GMC frame. I will be taking the front discs off to put on my 70 3/4 Chevy flatbed. But I was wondering what the rear axle is to see if maybe it is better than the one on my Chevy. Can someone help me decode it.

On the passenger side near the pumpkin, upside down, I read C-30255 on the top part and a 09 on the bottom part.

**JIMs70GMC** · 06-28-2005, 05:42 AM

that 09 read right side up is 60 for dana 60, does it look like this:

A dana 60 out of a leaf sprung 71 C20. As far as being better, that's debatable, is the axle in your chevy giving you any problems? Do you want taller(smaller number) rear gears? I assume you have the corporate(eaton) axle now.

RicksTrucks · 06-28-2005, 11:21 AM

Will the Dana 60 only work on a leaf spring truck? And is there a standard gear ratio for the 60? I will have to look at my Chevy to see what it is.

**JIMs70GMC** · 06-28-2005, 01:38 PM

I'm not sure if the dana60 came coil sprung, they were behind big blocks w/ autos and had 3.54 gears, the one in the picture was behind a 350 and had 4.10s.

RicksTrucks · 06-28-2005, 02:08 PM

So would it be safe to say that all Dana 60s that were in trucks were 4:10 ratio?

**JIMs70GMC** · 06-28-2005, 05:40 PM

Not exactly, 4.56s and 3.73 were also available.

thecatseye66 · 06-28-2005, 05:46 PM

Quote:

Originally Posted by JIMs70GMC

Not exactly, 4.56s and 3.73 were also available.

and 3:54's

**Classic Heartbeat** · 06-28-2005, 06:20 PM

Dana 60s were also installed under 2WD small block trucks with leaf spring rear ends. There is also a coil spring version of the Dana 60. They were installed under the Big Block Trucks and Suburbans with coil spring rear ends. I have both of the rear ends out here in my trucks...lol WES www.ClassicHeartbeat.com

RicksTrucks · 06-28-2005, 06:24 PM

So can anyone tell me an easy way to tell what ratio I have?

**JIMs70GMC** · 06-28-2005, 08:12 PM

pull the cover and change the gear oil and look on the ring gear the ratio will be stamped on it.

**uncle** · 06-28-2005, 08:13 PM

Look for a tag under one of the inspection cover bolts or pull the cover.

rwgregory · 06-29-2005, 03:12 AM

All Dana rears had gear tags installed from the factory

06-27-2005, 09:49 PM	#1
RicksTrucks Senior Member Join Date: Jan 2005 Location: Claremore, OK 74017 Posts: 2,640	Help with GMC rear axle decoding I have a 71 3/4 GMC frame. I will be taking the front discs off to put on my 70 3/4 Chevy flatbed. But I was wondering what the rear axle is to see if maybe it is better than the one on my Chevy. Can someone help me decode it. On the passenger side near the pumpkin, upside down, I read C-30255 on the top part and a 09 on the bottom part. __________________ 68 Short Stepside C-10 69 SWB C-10 70 Flatbed C-20 70 LWB C-20 BB402 70 LWB C-10 CST 70 LWB C-10 CST 71 Short Stepside Cheyenne C-10 72 LWB C-10 72 Blazer 4x4 4spd 95 Jeep Cherokee 4x4 Last edited by RicksTrucks; 06-27-2005 at 09:49 PM. Reason: correction

06-28-2005, 05:42 AM	#2
JIMs70GMC user # 2756 Join Date: Jun 2001 Location: Chesapeake, Virginia Posts: 4,612	that 09 read right side up is 60 for dana 60, does it look like this: A dana 60 out of a leaf sprung 71 C20. As far as being better, that's debatable, is the axle in your chevy giving you any problems? Do you want taller(smaller number) rear gears? I assume you have the corporate(eaton) axle now. __________________ 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 Last edited by JIMs70GMC; 06-28-2005 at 05:44 AM.

06-28-2005, 11:21 AM	#3
RicksTrucks Senior Member Join Date: Jan 2005 Location: Claremore, OK 74017 Posts: 2,640	Will the Dana 60 only work on a leaf spring truck? And is there a standard gear ratio for the 60? I will have to look at my Chevy to see what it is. __________________ 68 Short Stepside C-10 69 SWB C-10 70 Flatbed C-20 70 LWB C-20 BB402 70 LWB C-10 CST 70 LWB C-10 CST 71 Short Stepside Cheyenne C-10 72 LWB C-10 72 Blazer 4x4 4spd 95 Jeep Cherokee 4x4

06-28-2005, 01:38 PM	#4
JIMs70GMC user # 2756 Join Date: Jun 2001 Location: Chesapeake, Virginia Posts: 4,612	I'm not sure if the dana60 came coil sprung, they were behind big blocks w/ autos and had 3.54 gears, the one in the picture was behind a 350 and had 4.10s. __________________ 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

06-28-2005, 02:08 PM	#5
RicksTrucks Senior Member Join Date: Jan 2005 Location: Claremore, OK 74017 Posts: 2,640	So would it be safe to say that all Dana 60s that were in trucks were 4:10 ratio? __________________ 68 Short Stepside C-10 69 SWB C-10 70 Flatbed C-20 70 LWB C-20 BB402 70 LWB C-10 CST 70 LWB C-10 CST 71 Short Stepside Cheyenne C-10 72 LWB C-10 72 Blazer 4x4 4spd 95 Jeep Cherokee 4x4

06-28-2005, 05:40 PM	#6
JIMs70GMC user # 2756 Join Date: Jun 2001 Location: Chesapeake, Virginia Posts: 4,612	Not exactly, 4.56s and 3.73 were also available. __________________ 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

06-28-2005, 06:20 PM	#8
Classic Heartbeat Project Junkie! Fishing Poor!! Join Date: Dec 1999 Location: Olympia,Wa. 98512 Posts: 10,770	Dana 60s were also installed under 2WD small block trucks with leaf spring rear ends. There is also a coil spring version of the Dana 60. They were installed under the Big Block Trucks and Suburbans with coil spring rear ends. I have both of the rear ends out here in my trucks...lol WES www.ClassicHeartbeat.com __________________ On-line catolog Classic Heartbeat Pickup Parts WEHEPP@comcast.net Call us Toll Free (888) 338-2502 Like Us on Facebook No appointment necessary. 72 BB Chevy Custom Deluxe / Custom Camper 67 I-6 (Soon to be 5.7 LS1) Panel 68 BB Chevy Short Bed 72 6.0 LQ9 Short Bed Chevy 4X4 Olympia's fastest growing truck parts supplier. Olympia's home for Wayward Chevys

06-28-2005, 06:24 PM	#9
RicksTrucks Senior Member Join Date: Jan 2005 Location: Claremore, OK 74017 Posts: 2,640	So can anyone tell me an easy way to tell what ratio I have? __________________ 68 Short Stepside C-10 69 SWB C-10 70 Flatbed C-20 70 LWB C-20 BB402 70 LWB C-10 CST 70 LWB C-10 CST 71 Short Stepside Cheyenne C-10 72 LWB C-10 72 Blazer 4x4 4spd 95 Jeep Cherokee 4x4

06-28-2005, 08:12 PM	#10
JIMs70GMC user # 2756 Join Date: Jun 2001 Location: Chesapeake, Virginia Posts: 4,612	pull the cover and change the gear oil and look on the ring gear the ratio will be stamped on it. __________________ 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

06-28-2005, 08:13 PM	#11
uncle Senior Member Join Date: Aug 2003 Location: Conyers,Ga. Posts: 7,286	Ratio Look for a tag under one of the inspection cover bolts or pull the cover.

06-29-2005, 03:12 AM	#12
rwgregory Registered User Join Date: Apr 2005 Location: Chula Vista, California Posts: 495	All Dana rears had gear tags installed from the factory __________________ rwgregory 67 GMC 2500 ,2w/d wide box 305 V-6, 4-speed



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