The 1947 - Present Chevrolet & GMC Truck Message Board Network







Register or Log In To remove these advertisements.

Go Back   The 1947 - Present Chevrolet & GMC Truck Message Board Network > General Truck Forums > Engine & Drivetrain

Web 67-72chevytrucks.com


Reply
 
Thread Tools Display Modes
Old 01-28-2010, 06:55 PM   #1
Winston301
Registered User
 
Join Date: Dec 2009
Location: Des Moines, IA
Posts: 23
Question RPO code GQ1

GQ1 - Axle, Std Ratio

I am looking at a 14 bolt sf rear end out of a 82 3/4 ton. It has the 6.2 diesel w/ 400 trans. Does anyone know what the STANDARD RATIO would be?
Thank you!
Winston301 is offline   Reply With Quote
Old 01-28-2010, 11:41 PM   #2
C-10 simplex
Account Suspended
 
Join Date: Dec 2008
Location: indisclosed
Posts: 1,515
Re: RPO code GQ1

GQ1 is 2.56.

The other thing you could do is go to any gm dealer(preferably chevy) and they can type the vin# in the computer and look it up for you.

Last edited by C-10 simplex; 01-28-2010 at 11:42 PM.
C-10 simplex is offline   Reply With Quote
Old 01-29-2010, 10:01 AM   #3
Winston301
Registered User
 
Join Date: Dec 2009
Location: Des Moines, IA
Posts: 23
Re: RPO code GQ1

That is a good idea C-10. I will probably do that. Thank you.
Winston301 is offline   Reply With Quote
Old 01-29-2010, 12:31 PM   #4
D13
Registered User
 
D13's Avatar
 
Join Date: Feb 2007
Location: Memphis MI
Posts: 1,851
Re: RPO code GQ1

If it's truely a 14b SF 9.5" then the 'standard' ratio would be 3.42. The lowest numeric ratio would be a 3.23 (unusual) and the highest 4.56.

The standard ratio on my 81 3/4 with a L6 250 and 3OTT is a 3.42.

The term 'standard' means that the customer didn't order anything special. What was 'standard' varied with engine and trans. For example, a 454 in a half ton would get a different ratio than the same in a 3/4 ton, because it was assumed that the half ton was for occasional towing and the 3/4 ton was for heavy loads. Plus the differnece in the tire sizes and the torque capability in the axles which might restrict the gear ratios available.
__________________
1987 2 ton
1982 250/TH350 beater in progress
Dad's 1981 3/4 L6 3 on tree posi and no options, awaiting restoration or scrapping
Plus a mess o' tractors

Last edited by D13; 01-29-2010 at 12:34 PM.
D13 is offline   Reply With Quote
Old 01-29-2010, 02:57 PM   #5
C-10 simplex
Account Suspended
 
Join Date: Dec 2008
Location: indisclosed
Posts: 1,515
Re: RPO code GQ1

oh yeah....scratch that. i thought we were dealing with 1/2 ton---i forgot about the 3/4 ton part.


This is interesting and useful info.

Last edited by C-10 simplex; 01-29-2010 at 03:06 PM.
C-10 simplex is offline   Reply With Quote
Old 01-29-2010, 03:23 PM   #6
C-10 simplex
Account Suspended
 
Join Date: Dec 2008
Location: indisclosed
Posts: 1,515
Re: RPO code GQ1

Well, to complicate matters further(i always do this,

EDIT comments withdrawn----the matter is too complicated for me.

b) Additionally, apparently std ratio varied from yr to yr. For instance my 83 1/2 ton is 2.56 as std ratio(which i thought applied across the board from 81-87 in all weight ratings but apparently not so)

c) i now think, due to more info/intervention by D13+more research(brouchures) you got a 3.08 because of the diesel engine, but i think it's best at this point i withdraw from the thread due to the increasing complexity of the situation and merely observe and learn.

Last edited by C-10 simplex; 01-29-2010 at 03:33 PM.
C-10 simplex is offline   Reply With Quote
Old 01-29-2010, 04:05 PM   #7
Winston301
Registered User
 
Join Date: Dec 2009
Location: Des Moines, IA
Posts: 23
Re: RPO code GQ1

Well, I emailed my local GM dealer & he said he couldn't look anything up because of how old it is. He went out in the shop & asked a few mechanics & they said 3.08 (2.75 if it was 2wd).

I am planning to grab a shovel & dig the truck out of the snow & get it figured out. It is supposed to be a balmy 17 degrees here tomorrow so why not do a little work outside.

Stay tuned!
Winston301 is offline   Reply With Quote
Old 01-30-2010, 09:34 AM   #8
D13
Registered User
 
D13's Avatar
 
Join Date: Feb 2007
Location: Memphis MI
Posts: 1,851
Re: RPO code GQ1

3.08's are the most common half ton ratio, all thruout the 70'sm 80's, and even 90's. My 87 6.2 700R4 has them, as well as my 84 250 TH350 and my 83 305 TH350.

BUT the original post said that it was a 14b SF, which would be the 9.5" ring gear, which would be a light 3/4 ton. The only gearsets available for that rear are the 3.23, 3.42, 3.73, 4.11, and 4.56. The 3.42 is by far the most common original gear, followed by the 4.11 (usually a towing package) and 3.73 (usualy a camper package or HD GVW) I've never seen a 4.56 factory in person, usually by time that much torque is needed they would step up to the 10.5" or the Dana. The 3.23 would seem to be a highway gear with 16" rims and factory tires. The only one I've seen was a 4wd, a light 3/4 ton pickup. It's interesting to note that this is the only ratio not available aftermarket - must not have made many.
__________________
1987 2 ton
1982 250/TH350 beater in progress
Dad's 1981 3/4 L6 3 on tree posi and no options, awaiting restoration or scrapping
Plus a mess o' tractors

Last edited by D13; 01-30-2010 at 09:35 AM.
D13 is offline   Reply With Quote
Old 02-01-2010, 10:31 AM   #9
Winston301
Registered User
 
Join Date: Dec 2009
Location: Des Moines, IA
Posts: 23
Re: RPO code GQ1

I thank everyone for their input. Me & a buddy dug it out from the snow drift & figured it out. Even with the 6.2 it has 4.11 gears. I'm not sure why 4.11 would be the standard ratio for that setup. I don't see someone changing both front & rear gears but I guess it is a possibility it could have happened.

Again, Thanks for all the input!
Winston301 is offline   Reply With Quote
Reply

Bookmarks

Tags
14 bolt, gear, rear axle, rpo codes


Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -4. The time now is 09:20 AM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
Copyright 1997-2022 67-72chevytrucks.com