Rear End Ratio RPO Codes Here

[raxafarian]

Originally Posted by Jimmy V

I just took a peak in my truck and i have the G80 rear end....do you know a website where i can look up teh rest of the codes????

this seems like a good list... there are 4 different sections by year:
http://www.c2e.info/rpocodes/rpomain.html

there's another post with a link to a pdf file listing codes: http://www.fullsizechevy.com/forums/...ghlight=rpo%2A

[cantburn]

Thanks for posting the codes...worked out well.

[sandruvious]

got a problem my glove box does not have a sticker in it. I have a 66 C10 I want to know the gearing in the rear end how can I tell with out taking the cover off and checking that way?

[Sternzy]

heyah, I have a 1988 Chevy k1500, standard cab, longbed, w/305. The truck has great power in 4low, but in 4hi and 2hi it is apparently geared way to high, the clutch has to be sliped on hill starts and the engine bogs down.

I looked for my rpo code, and ofcourse the sticker in the glove box is warn where it lists the rear axle ratio code. =(

Anyone know what ratio might come stock with this cheyenne truck? I'm also looking to find out what gearing is recommended, and where I can order it from. I guess I'm looking for an extra low first gear, and hopefully get relitivly high by 4th gear.

Thx!
Sternzy

p.s. it has a 4 speed Manual.

[chevynut]

I just got an axle out of a 2002 and did not get the code out the glove box. I know the old camaros have a code stamped on the pass side axle tube. Is there any such coding stamped onto a 2002 truck axle?

thanks, Mike

[MISTA350]

should be similar on the truck axle

[codybug1970]

Wondering if you could help me with a Rearend problem??? I have a 1996 Z-71 with a 10-bolt, 3.73 open diff. rearend. My truck has 197,000 miles and the rearend just went and took the housing with it. I need to know how I can tell the ratio of a replacement if it isn't in the truck. I have found some that have already been removed and I don't want to buy the wrong ratio. These things aren't cheap!!!

[kenman1717]

Originally Posted by 454ss

This is all I got from the GQ1 so see if you find any of this codes listed below.
GQ1 : AXLE, STD RATIO
GS1 : AXLE REAR, 2.73 RATIO
GS3 : AXLE REAR, 3.73 RATIO
GS4 : AXLE REAR, 3.70 RATIO
GS5 : AXLE REAR, 4.11 RATIO
GS6 : AXLE REAR, 4.56 RATIO
GT1 : AXLE REAR, 2.56 RATIO
GT2 : AXLE REAR, 2.29 RATIO
GT4 : AXLE REAR, 3.73 RATIO (DUP WITH 5 X 1)
GT5 : AXLE REAR, 4.10 RATIO (DUP WITH GT8)
GT7 : AXLE REAR, 3.33 RATIO
GT8 : AXLE REAR, 4.10 RATIO (DUP WITH GT5)
GTY : AXLE, WIDE TRACK
GU1 : AXLE REAR, 2.41 RATIO
GU2 : AXLE REAR, 2.73 RATIO

well i found out a while ago i had the GT4 code- 3.73 gears, i didn't see a GQ1 or a G80, so does that mean anything, and what does that DUP WITH 5 x 1 mean. another thing, that code above, GS3 - 3.73 ratio, is that the same as the GT4 - 3.73 ratio.

[suchacinch]

Well i looked in the glove box to see what my codes meant and i,m almost positive it,s not right ,and here,s why . first of all the codes are GQ1 STD RATIO, and GU4 3.08 haha .
thats as ****ty as it gets. i have a 5.7 litre that runs like a scalded a** ape. I have lots of power off the line and if i punch it i lay down two strips of rubber ,i put on the 33 inch tires and it doesnt seem to have any effect on the truck . i,m fixing to replace the gasket on the diff cover so can someone tell me how to tell what the gears are for sure by counting the gears , i cant remember what you divide or whatever . also if they are 3.08 will the gears from a 83 chev truck work , or a 65 chevy truck ? thanks

[kenman1717]

Originally Posted by suchacinch

Well i looked in the glove box to see what my codes meant and i,m almost positive it,s not right ,and here,s why . first of all the codes are GQ1 STD RATIO, and GU4 3.08 haha .
thats as ****ty as it gets. i have a 5.7 litre that runs like a scalded a** ape. I have lots of power off the line and if i punch it i lay down two strips of rubber ,i put on the 33 inch tires and it doesnt seem to have any effect on the truck . i,m fixing to replace the gasket on the diff cover so can someone tell me how to tell what the gears are for sure by counting the gears , i cant remember what you divide or whatever . also if they are 3.08 will the gears from a 83 chev truck work , or a 65 chevy truck ? thanks

if it is 2wd then that 3.08 sounds about right.

[showplace]

does anybody know what RPO stands for and how does it determine if you can have a plow on ur truck or not? thanx.. .

[addiction2bass]

unless ya have 4x4 plowing would be kinda stupid......
doesnt matter which rear gears you have.... just depends how much ya push the gas and how much traction you got....

[jpel3500]

Awsome, awsome, awsome!!!!!!!!!!! And just in case I didn't mention it, AWSOME!

From the technical posts, I found out every code on my truck, except one. But I think I am guessing correctly. A little help here would be great. LOL At the ratio code, only one digit is not rubbed off. it is a 5... at the end. I have a 96 3500, with a limited slip, hydramatic 4L80-e transmission,and 14 bolt rear end. Now, from what I can see, I have a few choices on the ratio.
g75 3.62
g95 economy (wtf?!)
gs5 4.11
gt5 4.10 (dup w/gt8)
gu5 3.23
gv5 3.55
gw5 2.73
gt8 4.10 (dup w/gt5)

I am kind of assuming, since it was a one ton work truck that the gears are going to be pretty high, so I figure the 4.10 or 4.11...... furthermore, I am kind of assuming that the "dup with" designation sort of means that it is a 4 wheel drive. Soooooooo.. in conclusion... (as a question LOL) Do you think I have the gs5?

Thanks for all the wonderful info, and thanks for reading through this. LOL

JDPelfrey

[87CustomDeluxe]

What is the STD Ratio

[kenman1717]

Originally Posted by 87CustomDeluxe

What is the STD Ratio

what ever the standard ratio is at the time. i'm not sure but myself personally have only seen STD ratio, along side the 3.42 ratio, but i could be wrong.

[koltrain]

Cool I have a 3.42 axle ratio and positrac. That'll help in the winter with 2WD!!!

[chevynut]

I was wondering if there is a "code" actually stamped on the rear axle. not in the glove box?

Anyone know?

thanks, Mike

[kenman1717]

Originally Posted by chevynut

I was wondering if there is a "code" actually stamped on the rear axle. not in the glove box?

Anyone know?

thanks, Mike

i think on some of the older pre 88 ones there was, otherwise you would have to take the diff cover off and count the teeth, or rotations of the driveshaft for every one turn of the tire, 3.5 turns of the driveshaft, 3.42 gears, 3.75 turns, 3.73 gears, etc.

[mrmotoguzzi00]

First Post, Be Gentle ;)

I have the G80/GU5 rear end posi/3.23 and it ain't locking up when I hit the gas... ;(

This is a brand new 06 silverado, 1,800 miles, 4.8, 5 speed, WT long bed. I special ordered this because I wanted the V8 5 speed with posi. (I ordered the 3.73 posi, got screwed up and came in with the 3.23...)

Am I going to get anywhere with the dealer complaining about this ?

I have to go in next week to talk them about the funky voltage guage and dents on top of the bed anyway.... I hope they do right by me..

Thanks,

Mike

[LugnutGMC]

I have a 14bolt 3.73 in a 6 lug 2500, with G-80, lighter duty 7200 GVW, responding to someone asking if anyone had seen something like that.

For those of you finding that your codes dont match up with what you think you have, I broke my first glovebox, so i replaced it with one from a parts truck, so those codes dont match up at all, I saved the old one for reference. It'd be nice if the codes were in a more permanent place.

As for the G-80, my truck has 200,000 plus miles, its always been a plow truck and I drive it extremley hard, burnouts, offroading, tromping it off the line, and the limited slip has always held up. The G-80 def. isnt the best limited slip out there, but it gets the job done for me, its not a locker, where you press a button (air or electronic) and it stays locked. Because its pure mechanical it doenst work perfect all the time, but usually if I turn the wheels slowly it will lock up and get me unstuck. My friend has a 1999 3500 4wd with 4.10's and G80 and his locks up a lot more than mine, and almost always stays locked in 4wd, not sure if its cuz his has less miles on it, or if theres some sort of electronic locker when 4wd is engaged.

And RPO codes are Regular Production Option codes, like it was stated before, they apply to ALL GM vehicles from whenever they were first used, so G80 on a camaro, monte carlo, truck, or sedan is all the same. And it stays the same year to year. Z-71 (chassis package off-road), Z-28 (merchandised package, special performance) and Z-06 (special performance equipment package) are all RPO codes that are well known because people use them to refer to specific vheicles.

just to let showplace know, the code for the snow plow prep package is: VYU, but it doesnt mean you are ready to plow, I think its just heavier duty front springs, possible wiring already installed, etc.

http://www.c2e.biz/rpocodes/MODERNGMRPO.html