1972 GMC 3/4 ton rear axle ???? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Jtrux · 09-28-2008, 09:20 PM

A friend of mine (72LEVI) picked up a 72 3/4 ton GMC with a Dana rear axle. My question is, which one is it, a 60, 70 or ??? I don't know them a part by looking at them. Also I always hear of 3.54 gears in these axles, are those the only ones they came with?? Are they worth keeping in a truck?? If it's a 60 or 70 it should have lots of aftermarket support right??
Thanks.

hdflstf · 09-28-2008, 11:45 PM

Should be stamped on one of the webs as viewed from the rear.

DirtyLarry · 09-28-2008, 11:57 PM

Being a GMC it should be a leaf sprung Dana 60. 3:54 cogs is all I have ever seen but I am sure there were other gear ratios available.

72Levi · 09-29-2008, 12:06 AM

I might need to jack it up and turn wheels, mark driveshaft, etc... Jtrux is right its a Dana and other guys tell me its a 3.54 but Longhorn Man says it has rear suspension mods and most likely used as tow rig. The gears may have been changed, i will look. The leaf springs looked modded and it even has coils on shocks. See parts section, I am thinking Dana 60.

**special-K** · 09-29-2008, 05:49 AM

You`d know a Dana70 from a D60 if you saw one.That would be a way big rear.Like comparing a D44 front to a D60 front.The D60 came in the lower 4.10 and 4.56 as well.You hear alot about the 3.54 because it`s unusual for back then and great for today`s needs.Was that a big block originally?I saw the pics you sent,nice truck for the money,and noticed a later small block was dropped in and it has alot of options.The 1/2t big blocks trucks with automatics only came with 3.08s.I`d assume a big block/auto 3/4t would only come w/3.54.
You`ll find a "60",as mentioned,on the lower web in the center section.

Longhorn Man · 09-29-2008, 06:01 AM

tim, if you look at the photoi, it's a 3/4 ton (no 3.08 gears) and the truck has the remote power steering deal.

**special-K** · 09-29-2008, 06:33 AM

Gotcha,but I already knew that and it shows in my post.I only mentioned the 1/2t BBC ratio as part of my reasoning for assuming it would be 3.54s "if" it was in fact a BBC originally.

Longhorn Man · 09-29-2008, 03:31 PM

my bad man... I was scanning posts quickly before work.

**CPNE** · 09-29-2008, 03:39 PM

If that truck was originally a BB with a 4 speed transmission, it was probably a 4:10 (4:11) ratio. That's how my 72 Chevy longhorn BB was configured, with not option on spid IIRC. Granted mine was a 1 ton SRW so your mileage mary vary.

dfosh · 09-29-2008, 04:55 PM

I dont want to hijack , but i have the same problem .68 gmc 1/2 ton 250 six
im sure its a dana it has 354 gear. But i don't know which dana ? can someone post pictures of the different ones . My spid is gone .

**jamie72** · 09-29-2008, 05:12 PM

Quote:

Originally Posted by Longhorn Man

my bad man... I was scanning posts quickly before work.

gettin old...bud

Dooley · 09-29-2008, 05:20 PM

My 72 GMC (model noted as "wideside pickup" on title), 402 BB/T400 equipped C 3500 pickup had 3.73 Eaton rear gear. This was a special order truck with factory tach, spotlight, passenger side underbed toolbox, drivers side underbed fuel tank, rear overload springs and was a 8.5' bed. It was Fleet yellow with black interior. I had owned a 69 C20, 396/T400 Longhorn previous to this truck.

hounddogs! · 09-29-2008, 07:54 PM

3.54 Dana 60; yes there's some lube on the inside as well. At one time, it had a metal tag with 3.54 stamped on it.

Longhorn Man · 09-29-2008, 08:51 PM

3.54 was the standard gear on all big block 3/4 tons, 3 speed, 4 speed, or auto. It was not even avalible on one tons.
Dooley, do you have a spid showing your 3.73 gear? Or was that simply what you found in yours? Now granted, yours is a GMC, and there is little to no documentation on them, but chevy doesn't show 3/73 anywhere for any 3/4 or one ton trucks at all in the 67 - 72years.
dfosh, can you show a pic of your diff? If it's a dana, it should be a 60 (assuming 2 wheel drive here) and I've only heard of one 3.54 that was not in a big block truck... claimed to be original (a respected member, the ONLY reason I believe it is true)

factorystock · 09-29-2008, 09:03 PM

For some reason, Chevy never offered the 3.73 ratio on the C-20 Dana 60 3/4 tons between 68-72, while Dodge and Ford used this ratio in their Dana 60 3/4 tons.

1969 GMC · 09-29-2008, 10:13 PM

our trucks never got dana 70's, either. to visually id a 60 from a 70, the lip on the casting sticks farther down past the diff cover on a 70 than the 60, if for some reason you can't see or find any numbers.

**special-K** · 09-29-2008, 10:32 PM

My`72 K2500 has 3.54s and a 350.There were 1/2t Dana60s in some GMCs.

Andy,no problem.I hope I didn`t come off wrong there.Besides,it`s not like I make sense all the time.We should get together and check out rears sometime.

Longhorn Man · 09-29-2008, 10:35 PM

OK, 2 ppl that I trust about these trucks that have 3.54 rears in non big block trucks.

**special-K** · 09-29-2008, 11:20 PM

To your credit,I always thought they were 3.73s until you told me GMC didn`t offer that and did offer 3.54s.I never knew that.I checked mine and there they were.So,if you hadn`t corrected me you`d be right.(now,about what I said about me not making sense sometimes)

dfosh · 09-30-2008, 08:50 AM

I will post pic tommrow night . My son will have to do it for me . I did look at it again after seeing the above pic. Mine had a 4 on the web maybe a 44 as i could not make out the second # .tag on the cover was 46-13 3.54 . It also still had the paper sticker around the axel tube next to the backing plate .It was covred in dirt kinda brittle when i was cleaning .Number on it was 3903540 . Hope it showes in the pic when i post them. This truck was from the person that bought it new .

hounddogs! · 09-30-2008, 10:58 AM

46 and 13 are the tooth counts on the ring and pinion, respectively.

46/13 = 3.538 or your 3.54:1 ratio.

DirtyLarry · 09-30-2008, 01:03 PM

3:54 definitely was the standard gear as Longhorn man stated. Come to think of it I have never owned a single 67-72 two wheel drive that didn’t have 3:54 gears… Here is a few of the junk I have owned or still own.

1968 GMC C1500 305 V6/SM435 Dana 44 3:54 (parted). This truck’s rear axle is temporarily in my other ’68 GMC when the Dana 60 broke.

1968 GMC C1500 396BB/TH400 Dana 60(semi-floater: Rare) 3:54 (still have) Still have the broken semi-float Dana 60 as well. Something about those hard 1-2 TH400 shifts will a full race shift kit that tends to knock teeth off ring gears

1970 Chevy C10 402BB/SM465 Dana 44 3:54 (sold)

1972 Chevy C20 350/TH350 Eaton not sure of the gear ratio but the highway RPM’s are consistent of 3:54 (still have). I’ll have to chisel off the axle grime and look for a tag someday.

1972 K5 Blazer 3:73....4x4's were a different ball of gear wax anyway.

Travisarmenta · 01-03-2017, 01:04 PM

Back from the dead,

sooooo a 3/4 ton 2WD GMC Burb with a BB402/TH400 should have a Dana 60 with Leaf springs? or Coils?

09-28-2008, 09:20 PM	#1
Jtrux I'm a poor spectator Join Date: Aug 2006 Location: San Antonio, Tx Posts: 2,287	1972 GMC 3/4 ton rear axle ???? A friend of mine (72LEVI) picked up a 72 3/4 ton GMC with a Dana rear axle. My question is, which one is it, a 60, 70 or ??? I don't know them a part by looking at them. Also I always hear of 3.54 gears in these axles, are those the only ones they came with?? Are they worth keeping in a truck?? If it's a 60 or 70 it should have lots of aftermarket support right?? Thanks. __________________ 2006 Jeep Unlimited IMPACT ORANGE 1993 Chevy 2500 4x4 ExCab LWB 454/NV4500 Tow rig 1977 Ford F100 2x4 LWB 1st truck I owned, still have it!!! 1979 Ford F150 4x4 SWB Built Ford Tough!!! 1971 Chevy Blazer 350 / SM465 / NP205 UNDER CONSTRUCTION Soon to have a LQ4 6.0!!!

09-28-2008, 11:45 PM	#2
hdflstf Registered User Join Date: Oct 2007 Location: Desert Southwest Posts: 540	Re: 1972 GMC 3/4 ton rear axle ???? Should be stamped on one of the webs as viewed from the rear.

09-28-2008, 11:57 PM	#3
DirtyLarry Windy Corner of a Dirty Street Join Date: Jun 2003 Location: Pueblo West, Colorado Posts: 2,926	Re: 1972 GMC 3/4 ton rear axle ???? Being a GMC it should be a leaf sprung Dana 60. 3:54 cogs is all I have ever seen but I am sure there were other gear ratios available. __________________ Current vehicle collection: 1978 Chevrolet K10, 8.1L, NV4500, NP205 1989 Chevrolet Suburban, 8.1L, NV4500, NP241 1993 Chevrolet C1500 Sportside, TBI 7.4L, 4L60E 2001 Chevrolet K2500HD, Ext Cab, SWB, 8.1L, ZF 6 speed 2014 Chevrolet Impala LTZ 3.6L Vortec 8.1L because life is too short to tolerate underpowered vehicles Instagram

09-29-2008, 12:06 AM	#4
72Levi Active Member Join Date: Feb 2006 Location: sa tx Posts: 851	Re: 1972 GMC 3/4 ton rear axle ???? I might need to jack it up and turn wheels, mark driveshaft, etc... Jtrux is right its a Dana and other guys tell me its a 3.54 but Longhorn Man says it has rear suspension mods and most likely used as tow rig. The gears may have been changed, i will look. The leaf springs looked modded and it even has coils on shocks. See parts section, I am thinking Dana 60. __________________ 1972 K5 Blazer ALL ORIGINAL paint & engine, A/C, Tilt, 4sp, AM/FM, Tow Hooks, Aux Battery Tray, Tach, Vacuum 2004 FORD FX4 SuperCrew 2005 CTS-V 12 sec family car 2008 Buick Enclave AWD, Nav, & DVD, Wife LOVES it! Last edited by 72Levi; 09-29-2008 at 12:08 AM.

09-29-2008, 05:49 AM	#5
special-K Special Order Join Date: Nov 2004 Location: Mt Airy, MD Posts: 85,852	Re: 1972 GMC 3/4 ton rear axle ???? You`d know a Dana70 from a D60 if you saw one.That would be a way big rear.Like comparing a D44 front to a D60 front.The D60 came in the lower 4.10 and 4.56 as well.You hear alot about the 3.54 because it`s unusual for back then and great for today`s needs.Was that a big block originally?I saw the pics you sent,nice truck for the money,and noticed a later small block was dropped in and it has alot of options.The 1/2t big blocks trucks with automatics only came with 3.08s.I`d assume a big block/auto 3/4t would only come w/3.54. You`ll find a "60",as mentioned,on the lower web in the center section. __________________ "BUILDING A BETTER WAY TO SERVE THE USA"......67/72......"The New Breed" GMC '67 C1500 Wideside Super Custom SWB: 327/M22/3.42 posi.........."The '67" (project) GMC '72 K2500 Wideside Sierra Custom Camper: 350/TH350/4.10 Power-Lok..."The '72" (rolling) Tim "Don't call me a redneck. I'm a rough cut country gentleman" R.I.P. ~ East Side Low Life ~ El Jay ~ 72BLUZ ~ Fasteddie69 ~ Ron586 ~ 67ChevyRedneck ~ Grumpy Old Man ~

09-29-2008, 06:01 AM	#6
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	Re: 1972 GMC 3/4 ton rear axle ???? tim, if you look at the photoi, it's a 3/4 ton (no 3.08 gears) and the truck has the remote power steering deal.

09-29-2008, 06:33 AM	#7
special-K Special Order Join Date: Nov 2004 Location: Mt Airy, MD Posts: 85,852	Re: 1972 GMC 3/4 ton rear axle ???? Gotcha,but I already knew that and it shows in my post.I only mentioned the 1/2t BBC ratio as part of my reasoning for assuming it would be 3.54s "if" it was in fact a BBC originally. __________________ "BUILDING A BETTER WAY TO SERVE THE USA"......67/72......"The New Breed" GMC '67 C1500 Wideside Super Custom SWB: 327/M22/3.42 posi.........."The '67" (project) GMC '72 K2500 Wideside Sierra Custom Camper: 350/TH350/4.10 Power-Lok..."The '72" (rolling) Tim "Don't call me a redneck. I'm a rough cut country gentleman" R.I.P. ~ East Side Low Life ~ El Jay ~ 72BLUZ ~ Fasteddie69 ~ Ron586 ~ 67ChevyRedneck ~ Grumpy Old Man ~

09-29-2008, 03:31 PM	#8
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	Re: 1972 GMC 3/4 ton rear axle ???? my bad man... I was scanning posts quickly before work.

09-29-2008, 03:39 PM	#9
CPNE Resident Curmudgeon Join Date: Dec 1999 Location: NH Posts: 6,664	Re: 1972 GMC 3/4 ton rear axle ???? If that truck was originally a BB with a 4 speed transmission, it was probably a 4:10 (4:11) ratio. That's how my 72 Chevy longhorn BB was configured, with not option on spid IIRC. Granted mine was a 1 ton SRW so your mileage mary vary. __________________ Currently on or near the homestead: 67 Chevy SWB 2WD stepside 350/3 on tree (Pat's) 67 GMC SWB 2WD Fleet 402/auto (Brian's under construction) 67 Chevy 3/4 ton 2WD 402/auto (Business Hauler) 67 Chevy 1 ton dually 2WD 396/4 speed (Former business hauler, Needs TLC) 68 Chevy 1/2 ton Suburban 2WD 250 six/3 on tree (Brian's Needs TLC) 70 Chevy 3/4 ton 4WD 350/4 speed (Pat's - Disguised as a 68 GMC) 71 Chevy SWB stepside (Crushed by tree - parts donor) 72 Chevy 3/4 ton 4WD (Parts donor) 72 Chevy 3/4 ton 4WD Suburban (Parts Donor) 72 GMC 3/4 ton 4WD 292 six/4 speed (Mine - Disguised as a 67 GMC) 81 GMC 4WD Dually Dump Body 350/4 speed (Business Hauler) 82 Camaro Z/28 355/Super T-10 (Pat's toy) 93 Caprice 9C1 (Brian's Cop Car) 02 Toyota Camry (Reliable but a souless steel and plastic hulk) 2011 2SS RS Camaro M6 Factory Hurst Shifter Maybe I need to sell some of this crap Yet another Bozo with a sawz-all

09-29-2008, 04:55 PM	#10
dfosh Registered User Join Date: Oct 2007 Location: greeneville tn Posts: 237	Re: 1972 GMC 3/4 ton rear axle ???? I dont want to hijack , but i have the same problem .68 gmc 1/2 ton 250 six im sure its a dana it has 354 gear. But i don't know which dana ? can someone post pictures of the different ones . My spid is gone .

09-29-2008, 05:20 PM	#12
Dooley Registered User Join Date: Mar 2005 Location: North Coast Posts: 1,012	Re: 1972 GMC 3/4 ton rear axle ???? My 72 GMC (model noted as "wideside pickup" on title), 402 BB/T400 equipped C 3500 pickup had 3.73 Eaton rear gear. This was a special order truck with factory tach, spotlight, passenger side underbed toolbox, drivers side underbed fuel tank, rear overload springs and was a 8.5' bed. It was Fleet yellow with black interior. I had owned a 69 C20, 396/T400 Longhorn previous to this truck. Last edited by Dooley; 09-30-2008 at 01:13 AM.

09-29-2008, 07:54 PM	#13
hounddogs! Restoring it $200 at a time... Join Date: Aug 2008 Location: NE Kansas Posts: 886	Re: 1972 GMC 3/4 ton rear axle ???? 3.54 Dana 60; yes there's some lube on the inside as well. At one time, it had a metal tag with 3.54 stamped on it. Attached Images __________________ Charter member of the 'Put the dimmer switch back on the damn floor where it belongs' Society '68 5.3L-4 speed LWB C20; grandpa bought it for the farm in '71. Now LS 5.3, rather than 327. DD '09 Pilot Weekender '65 Skylark 300-4V-4 speed Wife's '07 Lexus ES350; 117 actuator motors and I can't see the engine. Son's '04 F250 SuperCab 6.0

09-29-2008, 08:51 PM	#14
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	Re: 1972 GMC 3/4 ton rear axle ???? 3.54 was the standard gear on all big block 3/4 tons, 3 speed, 4 speed, or auto. It was not even avalible on one tons. Dooley, do you have a spid showing your 3.73 gear? Or was that simply what you found in yours? Now granted, yours is a GMC, and there is little to no documentation on them, but chevy doesn't show 3/73 anywhere for any 3/4 or one ton trucks at all in the 67 - 72years. dfosh, can you show a pic of your diff? If it's a dana, it should be a 60 (assuming 2 wheel drive here) and I've only heard of one 3.54 that was not in a big block truck... claimed to be original (a respected member, the ONLY reason I believe it is true)

09-29-2008, 09:03 PM	#15
factorystock Registered User Join Date: Feb 2007 Location: west coast Posts: 3,380	Re: 1972 GMC 3/4 ton rear axle ???? For some reason, Chevy never offered the 3.73 ratio on the C-20 Dana 60 3/4 tons between 68-72, while Dodge and Ford used this ratio in their Dana 60 3/4 tons.

09-29-2008, 10:13 PM	#16
1969 GMC Registered User Join Date: Feb 2003 Location: The Rubber City Posts: 5,498	Re: 1972 GMC 3/4 ton rear axle ???? our trucks never got dana 70's, either. to visually id a 60 from a 70, the lip on the casting sticks farther down past the diff cover on a 70 than the 60, if for some reason you can't see or find any numbers. __________________ 1969 GMC K2500 1996 Honda Accord 2007 Kawasaki KLR 650



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09-29-2008, 10:32 PM	#17
special-K Special Order Join Date: Nov 2004 Location: Mt Airy, MD Posts: 85,852	Re: 1972 GMC 3/4 ton rear axle ???? My`72 K2500 has 3.54s and a 350.There were 1/2t Dana60s in some GMCs. Andy,no problem.I hope I didn`t come off wrong there.Besides,it`s not like I make sense all the time.We should get together and check out rears sometime. __________________ "BUILDING A BETTER WAY TO SERVE THE USA"......67/72......"The New Breed" GMC '67 C1500 Wideside Super Custom SWB: 327/M22/3.42 posi.........."The '67" (project) GMC '72 K2500 Wideside Sierra Custom Camper: 350/TH350/4.10 Power-Lok..."The '72" (rolling) Tim "Don't call me a redneck. I'm a rough cut country gentleman" R.I.P. ~ East Side Low Life ~ El Jay ~ 72BLUZ ~ Fasteddie69 ~ Ron586 ~ 67ChevyRedneck ~ Grumpy Old Man ~

09-29-2008, 10:35 PM	#18
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	Re: 1972 GMC 3/4 ton rear axle ???? OK, 2 ppl that I trust about these trucks that have 3.54 rears in non big block trucks.

09-29-2008, 11:20 PM	#19
special-K Special Order Join Date: Nov 2004 Location: Mt Airy, MD Posts: 85,852	Re: 1972 GMC 3/4 ton rear axle ???? To your credit,I always thought they were 3.73s until you told me GMC didn`t offer that and did offer 3.54s.I never knew that.I checked mine and there they were.So,if you hadn`t corrected me you`d be right.(now,about what I said about me not making sense sometimes) __________________ "BUILDING A BETTER WAY TO SERVE THE USA"......67/72......"The New Breed" GMC '67 C1500 Wideside Super Custom SWB: 327/M22/3.42 posi.........."The '67" (project) GMC '72 K2500 Wideside Sierra Custom Camper: 350/TH350/4.10 Power-Lok..."The '72" (rolling) Tim "Don't call me a redneck. I'm a rough cut country gentleman" R.I.P. ~ East Side Low Life ~ El Jay ~ 72BLUZ ~ Fasteddie69 ~ Ron586 ~ 67ChevyRedneck ~ Grumpy Old Man ~

09-30-2008, 08:50 AM	#20
dfosh Registered User Join Date: Oct 2007 Location: greeneville tn Posts: 237	Re: 1972 GMC 3/4 ton rear axle ???? I will post pic tommrow night . My son will have to do it for me . I did look at it again after seeing the above pic. Mine had a 4 on the web maybe a 44 as i could not make out the second # .tag on the cover was 46-13 3.54 . It also still had the paper sticker around the axel tube next to the backing plate .It was covred in dirt kinda brittle when i was cleaning .Number on it was 3903540 . Hope it showes in the pic when i post them. This truck was from the person that bought it new .

09-30-2008, 10:58 AM	#21
hounddogs! Restoring it $200 at a time... Join Date: Aug 2008 Location: NE Kansas Posts: 886	Re: 1972 GMC 3/4 ton rear axle ???? 46 and 13 are the tooth counts on the ring and pinion, respectively. 46/13 = 3.538 or your 3.54:1 ratio. __________________ Charter member of the 'Put the dimmer switch back on the damn floor where it belongs' Society '68 5.3L-4 speed LWB C20; grandpa bought it for the farm in '71. Now LS 5.3, rather than 327. DD '09 Pilot Weekender '65 Skylark 300-4V-4 speed Wife's '07 Lexus ES350; 117 actuator motors and I can't see the engine. Son's '04 F250 SuperCab 6.0

09-30-2008, 01:03 PM	#22
DirtyLarry Windy Corner of a Dirty Street Join Date: Jun 2003 Location: Pueblo West, Colorado Posts: 2,926	Re: 1972 GMC 3/4 ton rear axle ???? 3:54 definitely was the standard gear as Longhorn man stated. Come to think of it I have never owned a single 67-72 two wheel drive that didn’t have 3:54 gears… Here is a few of the junk I have owned or still own. 1968 GMC C1500 305 V6/SM435 Dana 44 3:54 (parted). This truck’s rear axle is temporarily in my other ’68 GMC when the Dana 60 broke. 1968 GMC C1500 396BB/TH400 Dana 60(semi-floater: Rare) 3:54 (still have) Still have the broken semi-float Dana 60 as well. Something about those hard 1-2 TH400 shifts will a full race shift kit that tends to knock teeth off ring gears 1970 Chevy C10 402BB/SM465 Dana 44 3:54 (sold) 1972 Chevy C20 350/TH350 Eaton not sure of the gear ratio but the highway RPM’s are consistent of 3:54 (still have). I’ll have to chisel off the axle grime and look for a tag someday. 1972 K5 Blazer 3:73....4x4's were a different ball of gear wax anyway. __________________ Current vehicle collection: 1978 Chevrolet K10, 8.1L, NV4500, NP205 1989 Chevrolet Suburban, 8.1L, NV4500, NP241 1993 Chevrolet C1500 Sportside, TBI 7.4L, 4L60E 2001 Chevrolet K2500HD, Ext Cab, SWB, 8.1L, ZF 6 speed 2014 Chevrolet Impala LTZ 3.6L Vortec 8.1L because life is too short to tolerate underpowered vehicles Instagram

01-03-2017, 01:04 PM	#23
Travisarmenta Registered User Join Date: Oct 2015 Location: Woodbridge Va Posts: 401	Re: 1972 GMC 3/4 ton rear axle ???? Back from the dead, sooooo a 3/4 ton 2WD GMC Burb with a BB402/TH400 should have a Dana 60 with Leaf springs? or Coils?

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