![]() |
Register or Log In To remove these advertisements. |
|
|
![]() |
|
Thread Tools | Display Modes |
|
![]() |
#1 |
Revitalizing a 6T C10
![]() Join Date: Aug 2017
Location: Santa Barbara, CA
Posts: 209
|
Help me decipher my parts truck (rear gear ratio - Dana 44)
Hey All,
I bought a 1978 GMC C15 High Sierra, that somebody had started pulling apart as a way to help get my 1960 back on the road. We have gotten down to the basics - I have the engine and subframe, as well as the rear end, but its current stored somewhere I can't get at it, and I am trying to do the math on gear ratios to help me finalize transmission point All I have with me at the moment is a slightly fuzzy picture of the sticker with codes .... The truck had leafs and what I believe was a Dana 44 With these option codes, can anybody help me sort the rear gear ratio from here? A28 DG4 F44 L59 N33 T44 XLB YF5 ZLB ZY4 64W A01 C60 B63 K30 MX1 N41 U35 XLB YLB ZQ2 Z62 68L Thanks!
__________________
1960 C-10 Apache- "Rusty the Redneck Reject"
1/2 Ton short bed step side. 350 crate motor, 3 speed manual (floor shifted) MKII - Buddy Buckets and Glass Packs 20+ year long term project in process Lots of Rust, more memories... |
![]() |
![]() |
![]() |
#2 |
Registered User
Join Date: Oct 2015
Location: IN
Posts: 209
|
Re: Help me decipher my parts truck (rear gear ratio - Dana 44)
None of those rpo codes are for the axle ratio. For the axle it would be Gxx or Hxx. Here's a listing of axle rpo codes.
https://www.differentials.com/gm-axl...ication-codes/ |
![]() |
![]() |
![]() |
#3 |
Senior Member
![]() Join Date: Mar 2003
Location: Colfax-California
Posts: 8,522
|
Re: Help me decipher my parts truck (rear gear ratio - Dana 44)
A 1978 is not going to have a dana 44 rear axle. Most likely a 10 or 12 bolt. Post a pic of the rear diff cover. Pull the cover anyways to get numbers off the ring gear, do an inspection and change the fluid
|
![]() |
![]() |
![]() |
#4 | |
Registered User
Join Date: May 2009
Location: Motor City
Posts: 9,194
|
Re: Help me decipher my parts truck (rear gear ratio - Dana 44)
Quote:
Probably your best bet since there are no guarantees the original ring and pinion are still in place after 45 years. K
__________________
Chevrolet Flint Assembly 1979-1986 GM Full Size Truck Engineering 1986 - 2019 Intro from an Old Assembly Guy: http://67-72chevytrucks.com/vboard/s...d.php?t=342926 My Pontiac story: http://forums.maxperformanceinc.com/...d.php?t=560524 Chevelle intro: http://www.superchevy.com/features/s...hevy-chevelle/ |
|
![]() |
![]() |
![]() |
#5 | |
Registered User
Join Date: May 2009
Location: Motor City
Posts: 9,194
|
Re: Help me decipher my parts truck (rear gear ratio - Dana 44)
Quote:
Additionally, if the truck has the base ratio it will not appear on the SPID or will show "GQ8 - Base ratio". If the person who ordered the truck had chosen an optional ratio then those typically do appear on the SPID with the corresponding RPO. Per the powertrain chart in the generic info packet the base ratio for a '78 C10 with L59 and federal emissions is a 3.07 (HE3). https://www.gm.com/content/dam/compa...olet-Truck.pdf K
__________________
Chevrolet Flint Assembly 1979-1986 GM Full Size Truck Engineering 1986 - 2019 Intro from an Old Assembly Guy: http://67-72chevytrucks.com/vboard/s...d.php?t=342926 My Pontiac story: http://forums.maxperformanceinc.com/...d.php?t=560524 Chevelle intro: http://www.superchevy.com/features/s...hevy-chevelle/ Last edited by Keith Seymore; 01-24-2024 at 01:32 PM. |
|
![]() |
![]() |
![]() |
#6 |
Revitalizing a 6T C10
![]() Join Date: Aug 2017
Location: Santa Barbara, CA
Posts: 209
|
Re: Help me decipher my parts truck (rear gear ratio - Dana 44)
does the fact that is a GMC (C15) vs a chevy (C10) make any difference
I am hoping to be where the truck is tomorrow, so I will take some better pictures, but here is what I have at the moment ![]() ![]() ![]() Thanks for all of the responses so far!
__________________
1960 C-10 Apache- "Rusty the Redneck Reject"
1/2 Ton short bed step side. 350 crate motor, 3 speed manual (floor shifted) MKII - Buddy Buckets and Glass Packs 20+ year long term project in process Lots of Rust, more memories... |
![]() |
![]() |
![]() |
#7 | |
Registered User
Join Date: May 2009
Location: Motor City
Posts: 9,194
|
Re: Help me decipher my parts truck (rear gear ratio - Dana 44)
Quote:
C10 vs C15 = marketing magic K
__________________
Chevrolet Flint Assembly 1979-1986 GM Full Size Truck Engineering 1986 - 2019 Intro from an Old Assembly Guy: http://67-72chevytrucks.com/vboard/s...d.php?t=342926 My Pontiac story: http://forums.maxperformanceinc.com/...d.php?t=560524 Chevelle intro: http://www.superchevy.com/features/s...hevy-chevelle/ |
|
![]() |
![]() |
![]() |
#8 |
Revitalizing a 6T C10
![]() Join Date: Aug 2017
Location: Santa Barbara, CA
Posts: 209
|
Re: Help me decipher my parts truck (rear gear ratio - Dana 44)
Kind of what I figured, but I could't find anything concrete on the option lists for GMC vs Chevy - I will try and grab some pictures, or crack the diff open and count the ratio anyways - appreciate your help!
- another Keith ![]()
__________________
1960 C-10 Apache- "Rusty the Redneck Reject"
1/2 Ton short bed step side. 350 crate motor, 3 speed manual (floor shifted) MKII - Buddy Buckets and Glass Packs 20+ year long term project in process Lots of Rust, more memories... |
![]() |
![]() |
![]() |
#9 | |
Registered User
Join Date: May 2009
Location: Motor City
Posts: 9,194
|
Re: Help me decipher my parts truck (rear gear ratio - Dana 44)
Quote:
A GMC is a Chevy with option Z88 "Nameplate conversion" added. (or - depending on your perspective - a Chevy is a GMC with option X88 added). ![]() All the rest of the options add and subtract in the same way regardless of brand. K
__________________
Chevrolet Flint Assembly 1979-1986 GM Full Size Truck Engineering 1986 - 2019 Intro from an Old Assembly Guy: http://67-72chevytrucks.com/vboard/s...d.php?t=342926 My Pontiac story: http://forums.maxperformanceinc.com/...d.php?t=560524 Chevelle intro: http://www.superchevy.com/features/s...hevy-chevelle/ |
|
![]() |
![]() |
![]() |
#10 |
Revitalizing a 6T C10
![]() Join Date: Aug 2017
Location: Santa Barbara, CA
Posts: 209
|
Re: Help me decipher my parts truck (rear gear ratio - Dana 44)
![]() ![]() ![]() ![]() ![]() ok, so I am seeing 14:43 = 3.07s open diff, is it just a "12 bolt" ?
__________________
1960 C-10 Apache- "Rusty the Redneck Reject"
1/2 Ton short bed step side. 350 crate motor, 3 speed manual (floor shifted) MKII - Buddy Buckets and Glass Packs 20+ year long term project in process Lots of Rust, more memories... |
![]() |
![]() |
![]() |
#11 |
Senior Member
![]() Join Date: Mar 2003
Location: Colfax-California
Posts: 8,522
|
Re: Help me decipher my parts truck (rear gear ratio - Dana 44)
ok, so I am seeing 14:43 = 3.07s open diff, is it just a "12 bolt" ?
Yes it is, nothing wrong with it. They are a good axle |
![]() |
![]() |
![]() |
#12 |
Revitalizing a 6T C10
![]() Join Date: Aug 2017
Location: Santa Barbara, CA
Posts: 209
|
Re: Help me decipher my parts truck (rear gear ratio - Dana 44)
Cool, thank you for confirming - it just helps me make sure I am ordering the right parts (trying to minimize time spent on the lift (re)ordering parts)
__________________
1960 C-10 Apache- "Rusty the Redneck Reject"
1/2 Ton short bed step side. 350 crate motor, 3 speed manual (floor shifted) MKII - Buddy Buckets and Glass Packs 20+ year long term project in process Lots of Rust, more memories... |
![]() |
![]() |
![]() |
Bookmarks |
Tags |
dana, ratio, rear |
|
|