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Username Post: GMT400 VIN decoding card        (Topic#251564)
someotherguy 
Senior Moderator
Posts: 28999
someotherguy
Age: 49
Loc: Texas
Reg: 08-01-03
10-25-10 09:49 AM - Post#1994704    

I spent some time this morning to come up with what I hope is an all-inclusive VIN decoding card for our GMT400 trucks. This info came from many sources - LMC 1988-1998 truck catalog, LMC 1992-1999 Blazer/Tahoe catalog, LMC 1992-1999 Suburban catalog, an uncredited site on angelfire Canada, GM's dealerworld site, and research using a collection of VIN's from my former salvage yard inventory.

Several sites have most of the info, but I couldn't find one that had all of it in one spot.

Please feel free to post/share it wherever you like. I prefer you use my direct link to post it, so as I make corrections, the new version will automatically replace the previous one. If you find any errors or omissions please let me know in an email (address is at bottom of the document) and I'll check it out and correct as needed.

If your browser or the forum software automatically resizes the image you may need to go to the direct link below and use the function in your browser to view the image full screen...or just print it out as a reference.

Direct link: http://www.someotherplace.com/info/GMT400VINCARD.J...



Richard

06 Silverado ISS / 06 Silverado SS / 06 300C SRT8


 
355Cheyenne 
Senior Member
Posts: 3781
355Cheyenne
Loc: Northern MN
Reg: 10-27-04
10-25-10 10:10 AM - Post#1994722    
    In response to someotherguy

VERY NICE.

98 Silverado k1500 4x4 350


 
Smither 
Member
Posts: 474
Smither
Loc: Central Illinois
Reg: 12-26-02
10-25-10 11:14 AM - Post#1994748    
    In response to someotherguy

Richard, you are the man. Thank you!

'04 Crew Cab
'95 C1500 Suburban
'95 GMC K1500


 
rodram 
Contributor
Posts: 381

Loc: Saskatoon, CANADA
Reg: 04-14-09
10-25-10 12:22 PM - Post#1994772    
    In response to Smither

thank you for this ... I have been curious about this information for my truck, but never took the initiative to look myself...



 
someotherguy 
Senior Moderator
Posts: 28999
someotherguy
Age: 49
Loc: Texas
Reg: 08-01-03
10-25-10 12:48 PM - Post#1994778    
    In response to rodram

Another neat thing is getting all your RPO codes - you can punch your VIN into this site:
http://www.compnine.com/vid.php

If it has your records on file, it will show you every RPO code your vehicle was made with and the description of the code. Not everything is there but I've had pretty good luck with it.

Richard

06 Silverado ISS / 06 Silverado SS / 06 300C SRT8


 
someotherguy 
Senior Moderator
Posts: 28999
someotherguy
Age: 49
Loc: Texas
Reg: 08-01-03
10-31-11 07:24 AM - Post#2152978    
    In response to someotherguy

Now that Compnine has sadly gone offline, a useful resource is gone. You can still perform the RPO decoding yourself, IF your SPID label (service parts identification) is still legible inside your glovebox, and it's the one original to your vehicle (check the last digits of the VIN against your dash tag.) Here's a post I just put up in the newer truck section regarding this info:

Decoding the VIN isn't that big of a deal; the information is out there. What Compnine was great for was returning to you all the RPO codes unique to your vehicle, and giving the description of each RPO. You can still do this...manually...if you have access to your RPO codes.

On the 88-98 fullsize trucks, the RPO codes are on a sticker inside the glovebox. I suspect they're in the same place or similar on the newer trucks. I strongly suggest you take a clear, close-up, digital picture of your sticker and save a copy of it on your computer for future reference, in case anything ever happens to it. On the 88-94 trucks many of them are illegible now because GM in their wisdom placed it on the floor of the glovebox; stuff rubbing on them over the years have scratched them badly.

Here is a link straight to GM with a lot of VIN decoding cards, particularly for the later model vehicles: http://service.gm.com/dealerworld/vincards/

For the 88-98 trucks I have compiled data from many different sources and made my own VIN decoding card: http://www.someotherplace.com/info/GMT400VINCARD.J...

This can tell you what country your truck was made in, manufacturing division, GVWR (gross vehicle weight rating), chassis type (2wd, 4wd), series (1/2 ton, 3/4 ton, etc.), body type, engine type, model year, and manufacturing plant.

You can decode your RPO list from your glovebox sticker by using one of the many collections of RPO codes found around the internet. These sites come and go over the years; I found one really complete reference and have hosted it on my site in hopes I can provide it in the event its other sources go away: http://www.someotherplace.com/info/RPO.pdf

Keep in mind that sometimes a particular RPO code can be recycled so it may not always mean the same thing from year to year, or model to model. For example, MT8 in this list indicates an 18 speed manual transmission (heavy truck) but on early 90's light trucks is actually the NV4500 5 speed. So, no list is 100% correct but this one will get you most of the way.

Richard

06 Silverado ISS / 06 Silverado SS / 06 300C SRT8


 
Vandura 61 
Forum Newbie
Posts: 27
Vandura 61
Loc: Ala Freaking Bama
Reg: 09-16-17
10-02-17 08:54 AM - Post#2709489    
    In response to someotherguy

How do you find the gear ratio, and trans number ? I went though all the RPO codes and still have not been able to find them.



 
Chevytech 
Subject Matter Expert - Senior Member
Posts: 3825
Chevytech
Loc: Twin Cities, Minnesota, U...
Reg: 04-25-04
10-02-17 02:29 PM - Post#2709519    
    In response to Vandura 61

  • Vandura 61 Said:
How do you find the gear ratio, and trans number ? I went though all the RPO codes and still have not been able to find them.


Axle ratio by RPO code

GU2 = 2.73
GU4 = 3.08
GU5 = 3.23
GU6 = 3.42
GT4 = 3.73
GT5 = 4.10

The RPO for the tranny will begin with an M

For those of you that are wondering why you are not getting replies to your thread:

Did you give the model, year, engine, fuel system type, and transmission information?

If your vehicle has been altered from stock, let us know about that too.


 
Keith Seymore 
Contributor
Posts: 728
Keith Seymore
Loc: Southeast Michigan
Reg: 09-17-08
10-06-17 09:22 AM - Post#2709925    
    In response to Chevytech

  • Chevytech Said:
  • Vandura 61 Said:
How do you find the gear ratio, and trans number ? I went though all the RPO codes and still have not been able to find them.


Axle ratio by RPO code

GU2 = 2.73
GU4 = 3.08
GU5 = 3.23
GU6 = 3.42
GT4 = 3.73
GT5 = 4.10

The RPO for the tranny will begin with an M



Just to expand on this a bit: if your vehicle is equipped with the standard axle for your combination then the code will show as "GQ1 - Standard Axle" without telling you the ratio. You will need access to the powertrain charts to know what ratio was used.

If you have an optional ratio then it will appear as described above.

K


Chevelle Intro: http://www.popularhotrodding.com/features/1005phr_...
My Pontiacs: http://forums.maxperformanceinc.com/forums/showthr...
Pickup: http://67-72chevytrucks.com/vboard/showthread.php?...


 
bowtie44s 
Valued Contributor
Posts: 4236
bowtie44s
Age: 36
Loc: wv
Reg: 08-29-12
10-06-17 09:26 AM - Post#2709926    
    In response to Keith Seymore

  • Keith Seymore Said:
Just to expand on this a bit: if your vehicle is equipped with the standard axle for your combination then the code will show as "GQ1 - Standard Axle" without telling you the ratio. You will need access to the powertrain charts to know what ratio was used.

If you have an optional ratio then it will appear as described above.

K




Could you explain that? I have never seen one without one of the codes listed.


Jeff

'88 Chevy K3500, aluminum head roller cam 511in³ stroker 10.5:1 compression, 96 NV 4500, 94-98 grille, 305/70-16 (33x12) BF Goodrich KM2s, 91 cluster swap


 
someotherguy 
Senior Moderator
Posts: 28999
someotherguy
Age: 49
Loc: Texas
Reg: 08-01-03
10-06-17 09:46 AM - Post#2709927    
    In response to bowtie44s

To the best of my knowledge, on the GMT400 light trucks the "standard axle ratio" is GU6 which is also 3.42. I definitely welcome any corrections though!

Richard

06 Silverado ISS / 06 Silverado SS / 06 300C SRT8


 
Vandura 61 
Forum Newbie
Posts: 27
Vandura 61
Loc: Ala Freaking Bama
Reg: 09-16-17
10-07-17 05:22 AM - Post#2710007    
    In response to someotherguy

This is on a 95 2500 van with a 5.7 auto 4L60-E, I can see the GU on the code but can't make out last number it is all smuged up, looks like a A but could be a 4 or 6 not sure. It is either a 3:08 or 3:42. Would like to know for sure though.



 
elcamino 
Dedicated Member
Posts: 5404
elcamino
Loc: Lake Superior-Michigan US...
Reg: 03-30-00
10-07-17 07:36 AM - Post#2710027    
    In response to Vandura 61

According the spec's only 2 ratio's with G10/G20 w/4L60E are;

GU6 - 3.42
GT4 - 3.73

Sorry if hard to read, the quality of the GM scanned pdf doc is the reason.


LINK to PDF Doc

Mike
2017 GMC Sierra Denali Ultimate 6.2L(420hp)/8-sp Z95
2018 Polaris RZR S 900 EPS


 
Vandura 61 
Forum Newbie
Posts: 27
Vandura 61
Loc: Ala Freaking Bama
Reg: 09-16-17
10-08-17 04:37 AM - Post#2710111    
    In response to elcamino

Ok Thanks for the info. It is a GU for sure, so it has to be a GU6 with a 3:42 gear.



 
deckeda 
Poster
Posts: 63

Reg: 08-13-18
08-13-18 05:01 PM - Post#2742970    
    In response to someotherguy

Thanks for this VIN and RPO info. I was able to learn my truck apparently was optioned with a 4.11 rear. The only option code that didn't pan out for me (for my year/model) was RPO code 95U.

The info shows "Majestic Amethyst" color exterior paint but mine's maroon or burgundy. Not sure what Chevy called that color in '89 (C3500).



 
someotherguy 
Senior Moderator
Posts: 28999
someotherguy
Age: 49
Loc: Texas
Reg: 08-01-03
08-13-18 06:01 PM - Post#2742973    
    In response to deckeda

Welcome to Chevytalk; yes the RPO codes can be tricky because some of them get recycled/repurposed over the years. Your 1989 paint code 95U would be garnet red metallic, also known as WA8815.

Richard

06 Silverado ISS / 06 Silverado SS / 06 300C SRT8


 
scrambldcj8 
Silver Supporting Member
Posts: 2490
scrambldcj8
Loc: Belchertown, MA
Reg: 04-06-03
08-13-18 06:45 PM - Post#2742975    
    In response to someotherguy

  • someotherguy Said:
Now that Compnine has sadly gone offline, a useful resource is gone. You can still perform the RPO decoding yourself, IF your SPID label (service parts identification) is still legible inside your glovebox, and it's the one original to your vehicle (check the last digits of the VIN against your dash tag.)

Richard



Awesome! Sticky this!!

Too bad GM doesn't offer replacement stickers for those of have the original which (sadly) became faded with time...or do they?




 
454cid 
Valued Contributor
Posts: 3117

Age: 46
Loc: West Michigan
Reg: 02-18-12
08-13-18 07:06 PM - Post#2742981    
    In response to deckeda

  • deckeda Said:
Thanks for this VIN and RPO info. I was able to learn my truck apparently was optioned with a 4.11 rear.



What was the RPO?


99 K3500 RCLB


 
runamukker 
Poster
Posts: 78

Reg: 01-01-18
08-13-18 07:49 PM - Post#2742993    
    In response to scrambldcj8

  • scrambldcj8 Said:

Awesome! Sticky this!!

Too bad GM doesn't offer replacement stickers for those of have the original which (sadly) became faded with time...or do they?




This is the only place I know of that does GM licensed SPID, etc. They are not cheap.
http://www.autodatalabels.com/


'92 K1500 Blazer Z71 350TBI 700R4 , 253,000 miles
'94 C1500 Cheyenne WT 350TBI 4L60e , 565,000 miles


 
scrambldcj8 
Silver Supporting Member
Posts: 2490
scrambldcj8
Loc: Belchertown, MA
Reg: 04-06-03
08-14-18 04:38 AM - Post#2743010    
    In response to runamukker

^^^

Is that replacement simply from a photo? Won't be of any use if original is faded into an unrecognizable state....



 
Keith Seymore 
Contributor
Posts: 728
Keith Seymore
Loc: Southeast Michigan
Reg: 09-17-08
08-31-18 12:01 PM - Post#2744936    
    In response to scrambldcj8

GM does not, but they are available in the aftermarket.

This guy can fix you up:

http://outintheshop.com/2.html

Chevelle Intro: http://www.popularhotrodding.com/features/1005phr_...
My Pontiacs: http://forums.maxperformanceinc.com/forums/showthr...
Pickup: http://67-72chevytrucks.com/vboard/showthread.php?...


 
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