I got a parts truck - The 1947 - Present Chevrolet & GMC Truck Message Board Network

**67 cst swb** · 07-12-2007, 08:09 PM

its a 69 GMC with a factory 6 cyl, Powerglide, & suppost to be a posi rearend, even has powersteering.
Here's my question...?
what are the rear end gear possibilities? What are they most likely to be behind a 6 cyl with a powerglide?
It would be awesome to be a 3.73 posi. But, I just hoping to hear the possibilities. The glove box door says nothing about rearend.
I won't be getting it home until the July 21-22nd weekend.

I will be parting out this truck, so watch for it on the Parts Board...

lpaine · 07-12-2007, 08:46 PM

It's probably lower gears-being that it has a 6-, but you'll never know until you take the diff cover off and count the gears. My '69 originally had a 6 & 4.57 gears, (apparently the 6 cylinder trucks usually had lower gears) let us know what you find.

**Palf70Step** · 07-12-2007, 09:14 PM

Probably a 3.73 unless the glove box sticker says other wise, but like was said no telling unless you can find the axle code or pull thecover.

**67 cst swb** · 07-12-2007, 09:29 PM

Glove box said nothing of the rear axle... owner said it was a posi. Well, it's encouraging that it might be a 3.73, or even 4.11 would be great for my project.
Thanks guys...

**LockDoc** · 07-12-2007, 10:01 PM

Bryan,

If you're not sure what ratio your rear axle is there is a code stamped into the axle tube (see pics) and you can go here and look it up in the "axle" section. You only need the first three letters at this site. If your truck originally came with a six cyl it probably would have had a lower geared rear end.

http://67-72chevytrucks.com/vboard/s...d.php?t=578793

LockDoc (Leon)

**67 cst swb** · 07-12-2007, 11:28 PM

I used to (still do somewhere) have an original GM book showing these rearend codes, just can't find it anywhere.
also, I only looked at the truck for 3 minutes. I'll find out more when I pick it up. I was just wondering the most likely ratio of a 6 cyl/P.Glide equipt truck, if the glovebox doesn't list anything. I'm assuming a 6 cyl/ PG only had 2 or 3 options... what is the most likely stock ratio...
Is it possible to be a 3.73 or 4.11 stock in that truck or are they more likely to be 2.73, 3.08 or something else.
So, when people say "lower geared" what does "Lower" mean? I've heard these terms for years, but don't know what it means numerically. Give me some examples of Lower. I'm assuming the opposite of lowered geared is higher geared... what are some gear ratio's that go along with these terms?

sdkid · 07-12-2007, 11:32 PM

Lower gears equal higher numbers....4:11, 3:73 etc. In my mind the 3:73 is the starting point for lower gears. I don't know how low they went in 1/2 ton. I'm going to assume thia is a 1/2 ton your getting.

**67 cst swb** · 07-12-2007, 11:44 PM

yes, 1/2ton GMC 2wd...
So, "Lower gears" are higher numerically??? "Higher gears" are lower numerically.
So, if 3.73's are the starting point, 4.11's are lower and 5.13's are very low...? am I following you...?
How did they come up with such terms...
I would think lower would refer to numerically lower, what does the "lower" refer to. Lower top speed (hehehehe)...

sdkid... congrats on the 1000th post

sdkid · 07-13-2007, 12:50 AM

Don't know how they came up with it. 3:73 is just my opinion of the starting point. Someone else may say different. I believe that is where the posi carriers change from series 3 to series 4 though. Which is why I tend to think the way I do. And yes, you're following me.

Thanks for the nod, look like you recently passed that milepost your self.

**LockDoc** · 07-13-2007, 08:27 AM

-
In this chart the first one is the highest and the last one is the lowest.
I don't know how the high and low were derived unless it is the number of teeth on the pinion in relation to the ring gear. The 2.56 has 16 teeth on the pinion and 41 teeth on the ring gear and the 4.10 has 10 teeth on the pinion and 41 teeth on ring gear, so the 4.10 has a "lower" number of teeth on the pinion in relation to the ring gear. Don't really know though....

Ratio 2.56:1 - Tooth Combination 41-16
Ratio 2.73:1 - Tooth Combination 41-15
Ratio 3.07:1 - Tooth Combination 43-14
Ratio 3.08:1 - Tooth Combination 40-13
Ratio 3.08:1 - Tooth Combination 37-12
Ratio 3.31:1 - Tooth Combination 43-13
Ratio 3.36:1 - Tooth Combination 37-11
Ratio 3.42:1 - Tooth Combination 41-12
Ratio 3.55:1 - Tooth Combination 39-11
Ratio 3.73:1 - Tooth Combination 41-11
Ratio 4.10:1 - Tooth Combination 41-10
Ratio 4.11:1 - Tooth Combination 37-9

LockDoc

**67 cst swb** · 07-13-2007, 12:48 PM

My boss just answered me that higher meant higher speed, and lower meant lower speed... I'm guessing in relation to top speed

68GMC454 · 07-13-2007, 12:53 PM

the higher the number,,the slower yoru going on the high way..being a 6 truck,,its gonna be geared low,,3:73 or might even be 4:56 isnt it.. depends on weather a guy form the city bought it,,or a farmer,,most of the ol famr trucks were geared really low...but man even with a 6,,they could crawl up out of ahole with a load...

Longhorn Man · 07-13-2007, 02:49 PM

if I am reading my book right, and they do word things funny, it'll be a 3.73 unless the engine was a 350 (which it wasn't) and it would be a 3.07. The powerglide was not avalible with the 396. (another moot point)
So, if there is no option listed for gearing, (same with posi, not listed, not equipped) and assuming left original, then it'll be a 3.73 open diff.

**67 cst swb** · 07-13-2007, 06:45 PM

Longhorn Man... Thank You... Just what I was looking for. Thank You very much everybody for responding...

07-12-2007, 08:09 PM	#1
67 cst swb Senior Member Join Date: Nov 2001 Location: Rapid City, SD Posts: 2,281	I got a parts truck its a 69 GMC with a factory 6 cyl, Powerglide, & suppost to be a posi rearend, even has powersteering. Here's my question...? what are the rear end gear possibilities? What are they most likely to be behind a 6 cyl with a powerglide? It would be awesome to be a 3.73 posi. But, I just hoping to hear the possibilities. The glove box door says nothing about rearend. I won't be getting it home until the July 21-22nd weekend. I will be parting out this truck, so watch for it on the Parts Board... __________________ My Trucks: 1967 Chevrolet Short Wide Box 327 TH350 9" w/3.90 gears paint will be White - Current Project 1967 Chevrolet Custom LWB 283 TH400 3.73 Posi, no-AC, no-PS, no-PB, bench-seat, small-window - mostly orig driver 1967 Chevrolet CST LWB originally a 327 TH400 3.73 Posi AC PS PB, had Buddy Buckets, Small Window - parts truck 1967 Chevrolet CST LWB, 283 MT 3.73 had Buddy Buckets, Panoramic Window - parts truck 2001 Chevrolet 3500 2WD Crew Cab Dually 8.1L Allison White

07-12-2007, 08:46 PM	#2
lpaine Registered User Join Date: Oct 2002 Location: Parksville, B.C. Canada Posts: 637	Re: I got a parts truck It's probably lower gears-being that it has a 6-, but you'll never know until you take the diff cover off and count the gears. My '69 originally had a 6 & 4.57 gears, (apparently the 6 cylinder trucks usually had lower gears) let us know what you find. __________________ 1969 G.M.C 3/4 Ton 920 (Canadian Version) 307 3 speed, currently apart 1998 Chevy 1/2 ton ex cab V-6 5 speed 1967 Chevy SWB - project truck; not started just yet

07-12-2007, 09:14 PM	#3
Palf70Step State of Confusion! Join Date: Jul 2002 Location: Gulfport, MS USA Posts: 47,249	Re: I got a parts truck Probably a 3.73 unless the glove box sticker says other wise, but like was said no telling unless you can find the axle code or pull thecover. __________________ Bill 1970 Chevy Custom/10 LWB Fleetside 2010 Toyota Tacoma PreRunner SR5 Double Cab - DD Member of Louisiana Classic Truck Club (LCTC) Bill's Gallery Life isn't tied with a bow, but it's still a gift. Live simply. Love generously. Care deeply. Speak kindly. Leave the rest to God!

07-12-2007, 09:29 PM	#4
67 cst swb Senior Member Join Date: Nov 2001 Location: Rapid City, SD Posts: 2,281	Re: I got a parts truck Glove box said nothing of the rear axle... owner said it was a posi. Well, it's encouraging that it might be a 3.73, or even 4.11 would be great for my project. Thanks guys... __________________ My Trucks: 1967 Chevrolet Short Wide Box 327 TH350 9" w/3.90 gears paint will be White - Current Project 1967 Chevrolet Custom LWB 283 TH400 3.73 Posi, no-AC, no-PS, no-PB, bench-seat, small-window - mostly orig driver 1967 Chevrolet CST LWB originally a 327 TH400 3.73 Posi AC PS PB, had Buddy Buckets, Small Window - parts truck 1967 Chevrolet CST LWB, 283 MT 3.73 had Buddy Buckets, Panoramic Window - parts truck 2001 Chevrolet 3500 2WD Crew Cab Dually 8.1L Allison White Last edited by 67 cst swb; 07-12-2007 at 09:30 PM.

07-12-2007, 10:01 PM	#5
LockDoc The Older Generation Join Date: Aug 2006 Location: Montezuma, Iowa Posts: 25,818	Re: I got a parts truck Bryan, If you're not sure what ratio your rear axle is there is a code stamped into the axle tube (see pics) and you can go here and look it up in the "axle" section. You only need the first three letters at this site. If your truck originally came with a six cyl it probably would have had a lower geared rear end. http://67-72chevytrucks.com/vboard/s...d.php?t=578793 LockDoc (Leon) Attached Images __________________ Leon Locksmith, Specializing In Antique Trucks, Automobiles, & Motorcycles (My Dually Pickup Project Thread) http://67-72chevytrucks.com/vboard/s...d.php?t=829820 - Last edited by LockDoc; 11-07-2014 at 10:05 AM.

07-12-2007, 11:28 PM	#6
67 cst swb Senior Member Join Date: Nov 2001 Location: Rapid City, SD Posts: 2,281	Re: I got a parts truck I used to (still do somewhere) have an original GM book showing these rearend codes, just can't find it anywhere. also, I only looked at the truck for 3 minutes. I'll find out more when I pick it up. I was just wondering the most likely ratio of a 6 cyl/P.Glide equipt truck, if the glovebox doesn't list anything. I'm assuming a 6 cyl/ PG only had 2 or 3 options... what is the most likely stock ratio... Is it possible to be a 3.73 or 4.11 stock in that truck or are they more likely to be 2.73, 3.08 or something else. So, when people say "lower geared" what does "Lower" mean? I've heard these terms for years, but don't know what it means numerically. Give me some examples of Lower. I'm assuming the opposite of lowered geared is higher geared... what are some gear ratio's that go along with these terms? __________________ My Trucks: 1967 Chevrolet Short Wide Box 327 TH350 9" w/3.90 gears paint will be White - Current Project 1967 Chevrolet Custom LWB 283 TH400 3.73 Posi, no-AC, no-PS, no-PB, bench-seat, small-window - mostly orig driver 1967 Chevrolet CST LWB originally a 327 TH400 3.73 Posi AC PS PB, had Buddy Buckets, Small Window - parts truck 1967 Chevrolet CST LWB, 283 MT 3.73 had Buddy Buckets, Panoramic Window - parts truck 2001 Chevrolet 3500 2WD Crew Cab Dually 8.1L Allison White Last edited by 67 cst swb; 07-12-2007 at 11:37 PM.

07-12-2007, 11:32 PM	#7
sdkid Registered User Join Date: Sep 2004 Location: Pierre SD Posts: 1,533	Re: I got a parts truck Lower gears equal higher numbers....4:11, 3:73 etc. In my mind the 3:73 is the starting point for lower gears. I don't know how low they went in 1/2 ton. I'm going to assume thia is a 1/2 ton your getting. __________________ I think the world needs a drink... Help somebody...If you can....VanZant We're not wrong, we're not sorry, and its probably gonna happen again. That's the truth about men. Tracy Byrd Member# 13924 '70 c10, 350/350 '68 c10 250/4spd '68 c10 no eng/trans fac ps/pb/ac/at (future father/sons project) '48 Chevy Loadmaster

07-12-2007, 11:44 PM	#8
67 cst swb Senior Member Join Date: Nov 2001 Location: Rapid City, SD Posts: 2,281	Re: I got a parts truck yes, 1/2ton GMC 2wd... So, "Lower gears" are higher numerically??? "Higher gears" are lower numerically. So, if 3.73's are the starting point, 4.11's are lower and 5.13's are very low...? am I following you...? How did they come up with such terms... I would think lower would refer to numerically lower, what does the "lower" refer to. Lower top speed (hehehehe)... sdkid... congrats on the 1000th post __________________ My Trucks: 1967 Chevrolet Short Wide Box 327 TH350 9" w/3.90 gears paint will be White - Current Project 1967 Chevrolet Custom LWB 283 TH400 3.73 Posi, no-AC, no-PS, no-PB, bench-seat, small-window - mostly orig driver 1967 Chevrolet CST LWB originally a 327 TH400 3.73 Posi AC PS PB, had Buddy Buckets, Small Window - parts truck 1967 Chevrolet CST LWB, 283 MT 3.73 had Buddy Buckets, Panoramic Window - parts truck 2001 Chevrolet 3500 2WD Crew Cab Dually 8.1L Allison White Last edited by 67 cst swb; 07-12-2007 at 11:51 PM.

07-13-2007, 12:50 AM	#9
sdkid Registered User Join Date: Sep 2004 Location: Pierre SD Posts: 1,533	Re: I got a parts truck Don't know how they came up with it. 3:73 is just my opinion of the starting point. Someone else may say different. I believe that is where the posi carriers change from series 3 to series 4 though. Which is why I tend to think the way I do. And yes, you're following me. Thanks for the nod, look like you recently passed that milepost your self. __________________ I think the world needs a drink... Help somebody...If you can....VanZant We're not wrong, we're not sorry, and its probably gonna happen again. That's the truth about men. Tracy Byrd Member# 13924 '70 c10, 350/350 '68 c10 250/4spd '68 c10 no eng/trans fac ps/pb/ac/at (future father/sons project) '48 Chevy Loadmaster

07-13-2007, 08:27 AM	#10
LockDoc The Older Generation Join Date: Aug 2006 Location: Montezuma, Iowa Posts: 25,818	Re: I got a parts truck - In this chart the first one is the highest and the last one is the lowest. I don't know how the high and low were derived unless it is the number of teeth on the pinion in relation to the ring gear. The 2.56 has 16 teeth on the pinion and 41 teeth on the ring gear and the 4.10 has 10 teeth on the pinion and 41 teeth on ring gear, so the 4.10 has a "lower" number of teeth on the pinion in relation to the ring gear. Don't really know though.... Ratio 2.56:1 - Tooth Combination 41-16 Ratio 2.73:1 - Tooth Combination 41-15 Ratio 3.07:1 - Tooth Combination 43-14 Ratio 3.08:1 - Tooth Combination 40-13 Ratio 3.08:1 - Tooth Combination 37-12 Ratio 3.31:1 - Tooth Combination 43-13 Ratio 3.36:1 - Tooth Combination 37-11 Ratio 3.42:1 - Tooth Combination 41-12 Ratio 3.55:1 - Tooth Combination 39-11 Ratio 3.73:1 - Tooth Combination 41-11 Ratio 4.10:1 - Tooth Combination 41-10 Ratio 4.11:1 - Tooth Combination 37-9 LockDoc __________________ Leon Locksmith, Specializing In Antique Trucks, Automobiles, & Motorcycles (My Dually Pickup Project Thread) http://67-72chevytrucks.com/vboard/s...d.php?t=829820 -

07-13-2007, 12:48 PM	#11
67 cst swb Senior Member Join Date: Nov 2001 Location: Rapid City, SD Posts: 2,281	Re: I got a parts truck My boss just answered me that higher meant higher speed, and lower meant lower speed... I'm guessing in relation to top speed __________________ My Trucks: 1967 Chevrolet Short Wide Box 327 TH350 9" w/3.90 gears paint will be White - Current Project 1967 Chevrolet Custom LWB 283 TH400 3.73 Posi, no-AC, no-PS, no-PB, bench-seat, small-window - mostly orig driver 1967 Chevrolet CST LWB originally a 327 TH400 3.73 Posi AC PS PB, had Buddy Buckets, Small Window - parts truck 1967 Chevrolet CST LWB, 283 MT 3.73 had Buddy Buckets, Panoramic Window - parts truck 2001 Chevrolet 3500 2WD Crew Cab Dually 8.1L Allison White

07-13-2007, 12:53 PM	#12
68GMC454 THE VILLIAGE IDIOT Join Date: Nov 2006 Location: Tooele, Utah Posts: 1,405	Re: I got a parts truck the higher the number,,the slower yoru going on the high way..being a 6 truck,,its gonna be geared low,,3:73 or might even be 4:56 isnt it.. depends on weather a guy form the city bought it,,or a farmer,,most of the ol famr trucks were geared really low...but man even with a 6,,they could crawl up out of ahole with a load... __________________ honestly honey,,i have no idea how that truck got here.

07-13-2007, 02:49 PM	#13
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,690	Re: I got a parts truck if I am reading my book right, and they do word things funny, it'll be a 3.73 unless the engine was a 350 (which it wasn't) and it would be a 3.07. The powerglide was not avalible with the 396. (another moot point) So, if there is no option listed for gearing, (same with posi, not listed, not equipped) and assuming left original, then it'll be a 3.73 open diff.

07-13-2007, 06:45 PM	#14
67 cst swb Senior Member Join Date: Nov 2001 Location: Rapid City, SD Posts: 2,281	Re: I got a parts truck Longhorn Man... Thank You... Just what I was looking for. Thank You very much everybody for responding... __________________ My Trucks: 1967 Chevrolet Short Wide Box 327 TH350 9" w/3.90 gears paint will be White - Current Project 1967 Chevrolet Custom LWB 283 TH400 3.73 Posi, no-AC, no-PS, no-PB, bench-seat, small-window - mostly orig driver 1967 Chevrolet CST LWB originally a 327 TH400 3.73 Posi AC PS PB, had Buddy Buckets, Small Window - parts truck 1967 Chevrolet CST LWB, 283 MT 3.73 had Buddy Buckets, Panoramic Window - parts truck 2001 Chevrolet 3500 2WD Crew Cab Dually 8.1L Allison White



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