78 diesel rear end! - The 1947 - Present Chevrolet & GMC Truck Message Board Network

78-5.3 · 11-13-2009, 11:52 PM

ok i havent got around to checking the ratio of my rearend all i can say is it was factory 5.7 diesel with and automatic transmission it has a 12 bolt in it oh i brought the truck off the original owner any idea what it could be with out popping the plate off

ghettoluxury · 11-14-2009, 12:05 AM

diesel probably 2.88's

kelgar50 · 11-14-2009, 12:26 AM

I had a 82 1/2 ton with the 6.2 diesel and it came with a 700r4 and 3.73 rears.

78-5.3 · 11-14-2009, 12:41 AM

Quote:

Originally Posted by kelgar50

I had a 82 1/2 ton with the 6.2 diesel and it came with a 700r4 and 3.73 rears.

that would be perfect!!

3r!c84 · 11-14-2009, 12:55 AM

pop the cover off.and start counting,and its probly time to change the gear oil anyways. and just use some RTV and seal it back up

KQQL IT · 11-14-2009, 01:21 AM

The diesel rear i had on the 77 was 2:73s.

Dooley · 11-14-2009, 08:20 AM

The standard axle gear in 1978 for the C10 diesel pickup was 2.76 ratio.

westofb · 11-14-2009, 08:39 AM

I think you could do a search on here on how to figure out what your rear diff gear ratio is. If memory serves me correct, you can do this: for posi rear jack up rear end (both rear wheels off the ground), spin tires one rotation, count rotations of drive shaft, example on tire spin to 3 and 3/4 drive shaft spins equals roughly 3.73 gear ratio. If it is an open diff ( one tire burn out), jack up one tire, spin it two rotations and count drive shaft rotations, two tire rotations and 3 3/4 drive shaft rotations equal roughly the same 3.73 rear gear rotation. In either instance, the amount of rotation of the drive shaft gives you roughly the rear gear ratio, 3 rotations = 3.00 ratio, 4 rot = 4.00 ratio, etc. I am sure this is one way to roughly get your gear ratio, if I have misspoken someone will chime in correct me.

rustyescott · 11-14-2009, 09:07 AM

my 81 has a 3.08

78-5.3 · 11-14-2009, 09:15 AM

Quote:

Originally Posted by KQQL IT

The diesel rear i had on the 77 was 2:73s.

but there was no diesel in 77???

KQQL IT · 11-14-2009, 06:27 PM

Quote:

Originally Posted by 78-5.3

but there was no diesel in 77???

Yes. But the 80 that was sitting at the local junkyard with the axle pads already welded on the bottom of it fit just right in my 77.

78-5.3 · 11-14-2009, 11:50 PM

Quote:

Originally Posted by Dooley

The standard axle gear in 1978 for the C10 diesel pickup was 2.76 ratio.

2.76 was standard with 3.08 and 3.42 options

if i punch the accerator on my truck it frys the tyres got me thinking its 3.42

3r!c84 · 11-15-2009, 02:09 AM

just take off the cover already! lol

78-5.3 · 11-15-2009, 10:53 AM

Quote:

Originally Posted by 3r!c84

just take off the cover already! lol

working on the front brakes today that will be might next project!!!

78-5.3 · 11-15-2009, 12:42 PM

Quote:

Originally Posted by westofb

I think you could do a search on here on how to figure out what your rear diff gear ratio is. If memory serves me correct, you can do this: for posi rear jack up rear end (both rear wheels off the ground), spin tires one rotation, count rotations of drive shaft, example on tire spin to 3 and 3/4 drive shaft spins equals roughly 3.73 gear ratio. If it is an open diff ( one tire burn out), jack up one tire, spin it two rotations and count drive shaft rotations, two tire rotations and 3 3/4 drive shaft rotations equal roughly the same 3.73 rear gear rotation. In either instance, the amount of rotation of the drive shaft gives you roughly the rear gear ratio, 3 rotations = 3.00 ratio, 4 rot = 4.00 ratio, etc. I am sure this is one way to roughly get your gear ratio, if I have misspoken someone will chime in correct me.

i spun my wheel 2 times for a total of 1 1/2 turns on the drive shaft~~

boatpuller · 11-15-2009, 12:48 PM

my 79 is the 3.08.

11-13-2009, 11:52 PM	#1
78-5.3 Registered User Join Date: Oct 2009 Location: Waterboro ,MAINE Posts: 547	78 diesel rear end! ok i havent got around to checking the ratio of my rearend all i can say is it was factory 5.7 diesel with and automatic transmission it has a 12 bolt in it oh i brought the truck off the original owner any idea what it could be with out popping the plate off

11-14-2009, 12:05 AM	#2
ghettoluxury Registered User Join Date: Apr 2009 Location: Waynesfield Ohio Posts: 1,991	Re: 78 diesel rear end! diesel probably 2.88's __________________ 1949 Five Window, 1973 Step Side, 2000 Z71

11-14-2009, 12:26 AM	#3
kelgar50 Registered User Join Date: Nov 2008 Location: Bako,CA Posts: 64	Re: 78 diesel rear end! I had a 82 1/2 ton with the 6.2 diesel and it came with a 700r4 and 3.73 rears.

11-14-2009, 12:55 AM	#5
3r!c84 Badass Join Date: Jan 2009 Location: lox. fl Posts: 4,586	Re: 78 diesel rear end! pop the cover off.and start counting,and its probly time to change the gear oil anyways. and just use some RTV and seal it back up __________________ Think outside the box? -84c10 (1stcar)→My Build← -00 Saturn 5spd drop a gear and disappear! 1/4:13:90

11-14-2009, 01:21 AM	#6
KQQL IT At the body shop. Join Date: Aug 2009 Location: Land of fruits and nuts. Posts: 5,254	Re: 78 diesel rear end! The diesel rear i had on the 77 was 2:73s. __________________ " That didnt make it any newer " " Dont antique the equipment "

11-14-2009, 08:20 AM	#7
Dooley Registered User Join Date: Mar 2005 Location: North Coast Posts: 1,012	Re: 78 diesel rear end! The standard axle gear in 1978 for the C10 diesel pickup was 2.76 ratio.

11-14-2009, 08:39 AM	#8
westofb I really hate wet sanding! Join Date: Dec 2008 Location: Brookfield, MO Posts: 601	Re: 78 diesel rear end! I think you could do a search on here on how to figure out what your rear diff gear ratio is. If memory serves me correct, you can do this: for posi rear jack up rear end (both rear wheels off the ground), spin tires one rotation, count rotations of drive shaft, example on tire spin to 3 and 3/4 drive shaft spins equals roughly 3.73 gear ratio. If it is an open diff ( one tire burn out), jack up one tire, spin it two rotations and count drive shaft rotations, two tire rotations and 3 3/4 drive shaft rotations equal roughly the same 3.73 rear gear rotation. In either instance, the amount of rotation of the drive shaft gives you roughly the rear gear ratio, 3 rotations = 3.00 ratio, 4 rot = 4.00 ratio, etc. I am sure this is one way to roughly get your gear ratio, if I have misspoken someone will chime in correct me. __________________ Jeff, 68 C-10 75 C-20, now a C-10! 10 F-150

11-14-2009, 09:07 AM	#9
rustyescott Registered User Join Date: Aug 2007 Location: clifton tx Posts: 209	Re: 78 diesel rear end! my 81 has a 3.08

11-15-2009, 02:09 AM	#13
3r!c84 Badass Join Date: Jan 2009 Location: lox. fl Posts: 4,586	Re: 78 diesel rear end! just take off the cover already! lol __________________ Think outside the box? -84c10 (1stcar)→My Build← -00 Saturn 5spd drop a gear and disappear! 1/4:13:90

11-15-2009, 12:48 PM	#16
boatpuller Registered User Join Date: Sep 2005 Location: Sun City West, Az Posts: 3,822	Re: 78 diesel rear end! my 79 is the 3.08. __________________ " Never look up a dead dogs butt."

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