Rear End Ratio RPO Codes Here

[88JunkTruck]

What Does This Mean?

On the first line of RPO codes in my Glove Box I have The code "GQ1" wich according to the chart means standard ratio.

On the second line of code I have "GU6" wich means 3.42 ration.

So wich is it? I am confused

Also on the third line of cades it says"LO3" is that for my 305?

let me know

Thanks All!!

[addiction2bass]

i belive that just means you dont have a posi or limited slip......... you got the same crap i got.LOL
is your truck slow as hell on take off? youve got the same engine and rear end i got in my extended cab and mine just blows!!!!!!!!

[Luke2kZ71]

Originally Posted by addiction2bass

ive looked around at my local junk yards AND NO ONE HAS A 4.10 OR 3.73
LOOKS LIKE I CANNT SWAP EM OUT

how much a new rear end cost from the dealership at cost? im setup thru my dads company to buy direct preaty cheap but ive never asked the cost for a rear end.

gears with install kit is like $225 or so... not too bad

[RyPkr_99]

Install kit? I thought gears had to be professionally installed with professional equipment otherwise things wouldn't mesh well?

[88JunkTruck]

Yeah,

My truck is way weak on take off.
Not that it means anything but my tires (tire!) won't spin unless I'm hammering it out of a turn in the rain!!!...now I know why, besides the LO3 of course.

I can barely get up to speed by the next light when I am loaded down or pulling our camper.

I thought it was my transmissions fault, I never realized I had such a crappy gear ratio and axle setup.

[addiction2bass]

ya sounds like my setup! ive been trying to find a 4.10 rear end complete but not coming up good at all so that sucks!
ive thought about even puting some smaller tires on it which should heklp ALITTLE BIT but not to much i dont think. not sure.....
but the rear end swap should help out alot! and if that dont work then ill go with a 350 engine swap.LOL

[Luke2kZ71]

Originally Posted by addiction2bass

ya sounds like my setup! ive been trying to find a 4.10 rear end complete but not coming up good at all so that sucks!
ive thought about even puting some smaller tires on it which should heklp ALITTLE BIT but not to much i dont think. not sure.....
but the rear end swap should help out alot! and if that dont work then ill go with a 350 engine swap.LOL

you will not find a 10 bolt with 4.10s complete, you are more likly to find a 14 bolt. but most likley it will be 8 lug.. and assuming you have a 5 lug, you may try and find one of the 454ss rear ends, i think they came with 4.10s

[addiction2bass]

so i should probably just buy the gears rip out the rear end and take it to a trany shop if they do rear end gear swaps......... would be best to just be able to throw it up in thier same day but hey. what can i do......

[diehrd]

I have a 93 2dr Full Size Blazer..Code G80 which I see is posi traction (Limited Slip)

However there are no other codes in my list that are like any that you show in this sticky ? Any way i can find out what my gear ratio is ?

[1BADBU]

Originally Posted by Jim Bob

GU6 G80

Wow. According to that, I have a 3.42 posi.

I'd sure like to stick that rear end under my Malibu and put the 3.73 from the 'bu in the truck.

Thanks, Brendan.

WHAT YEAR BU?
HMMM,,, DO WE KNOW EACH OTHER?
FROM MR MAYBE?

[PUSHROD]

I believe these codes are pretty much a standard across the board for GM for the most part they are located on the Service Parts Identification Label as stated in the glove box and you can reference the codes from a GM service manual usually they are listed in the General Information section in the front of the manual, also these manuals are what the techs actually use to fix your ride when you take your vehicle to a dealership I hope this helps. Thanks

[Hayaboosta]

Originally Posted by crh428

Maybe it is a locker, can't really trust info you find on the net, anyways. As for what a posi is, it basically uses clutch packs and springs instead of mechanically locking. It serves the same purpose, though. A locker is better, as posi's tend to wear out pretty quick

how do you know when the posi is wearing out? do a burn out and check the tracks? or do you have to take the cover off and check something inside? because my truck is a '96... both wheels turn when i do a burn out, but is there any way to look and see how much life the posi has left?

[Luke2kZ71]

Originally Posted by Hayaboosta

how do you know when the posi is wearing out? do a burn out and check the tracks? or do you have to take the cover off and check something inside? because my truck is a '96... both wheels turn when i do a burn out, but is there any way to look and see how much life the posi has left?

the stock g80 runs off clutches... so the more it gets used.... technically the less it is working. the g80 is really a awefull posi unit... i would reccomend getting a detroit... they are a nice locker

another good one would be a aurburn... but if u replace that, i would go ahead and adjust the gear ratio... and you are looking at about $800 in parts/labor.

[SimpleGreen]

Well, I guess I know why I run 2900 RPM @ 70 MPH. I have 3.42's and 27" tires...

[alwhite00]

Originally Posted by P379XL

Well, I guess I know why I run 2900 RPM @ 70 MPH. I have 3.42's and 27" tires...

Don't you have an overdrive? With O/D you should be around 2,085 - What year truck?

LK

[SimpleGreen]

93 4.3 V6, 3 speed. Puting 31's on soon so maybe that should slow the engine down.

[Luke2kZ71]

g80 is really crappy, and i dont think it should be considered a locker.... it uses clutch packs, which is basically what a lsd is....

to my knowledge it also only works when the tires are broken loose... like while peeling out, cause it is engadged with centrifugal force... so it only works during certain torque loads i guess.... which makes it a turd.

this detriot i have is like night and day....

another good way to tell if u have a decent posi/locker unit is.... to lift the rear end up, and spin a tire..... if the other one spins in the same direction, its a good unit, if the other tire spins in the oppisite direction, then u either have a crappy locker, or open differental. (no locker)

i do know that the g80 is notorious for blowing (i blew mine) and i reccomend to anyone who drives hard to replace it..... and if you tires are larger than 37" i recommend getting a new axle with a real locker. the 10 bolt just cant handle alot of abuse in it's stock state....


now for your street guys... you are probally alot better off than me (or the rest of the OR crowd), cause u dont have all the weight we offroad guys do! nor the stress created from offroad enviroments... but if any of your street guys are interested in upgrading preformance.... i would get a set of 3.73s with a auburn (a good lsd) or even 4.10s is you tires are 30" or bigger and you like torque...

and just a fyi for the new guys... a lsd is a limited slip differental

[ME_TOBSTER]

Luke you are speaking the gospel. I had a 97 Yukon 9" up and 37" I-rocs. the stock carrier lasted about 500 miles and then it looked like the picture from earlier in the thread. So then I went to an Auburn LSD and 4.56's from www.jegs.com. A total of $825.00 for parts and install. and it worked killer for 7-8 months. then back to problems. Tore it down and 5 teeth were broke off of the ring gear. thought it was not meshed properly. So I put in another set of 4.56's and ran for another 7 months and it went out again. long story short for everyonelse if you are lifting or putting horsepower to a 10 bolt it will NOT hold so go to a 14 bolt.

[banditnga]

i have an 88 one ton 3500 2wd. 350 with 4 speed manual no air. it shows gu6 in the glove box. i never would have thought it was a 3.42 i would have guessed 4.10 or 3.73.

[takmsdsm]

ok my 94 k1500 4.3l shows a GT4 on the first line.... but no other GXX codes anywhere else... i thought that there was supposed to be either a GQ1 or a G80 in there somewhere to signify and open or LSD rear end? the previous owner said it had the LSD cuz it said he would feel it engage sometimes, but i have never noticed this (maybe cuz i dont know what it feels like)...

can anyone out there offer any advice?