TH 400 Original?

[MyOldScottsdale23]

I just bought a 1985 GMC Sierra Classic 4x4. The P.O. Said it had a '92 350/TH350. I did some research and crawling around under the truck and found that it's a TH400, but the pan says TurboHydramatic Div. of GMC. Could this be the original trans?

[Blazin]

We have a 94 2500 4x4 that comes in a couple times of year for minor work, and a sticker. It was ordered original with a 350 / TH400.
I had an 86 C10 about 6 or 7 years ago that with a 4.3 / TH400 combo in it.
Could be its original, or it came with the motor swap.

[MyOldScottsdale23]

Is there a way to tell for sure. Like a number stamp on it somewhere, because the option sticker is still legible in the glove compartment. Or is there a way to look up the codes.

[zieg85]

With the codes we should be able to come up with an answer. 

[bake74]

Is there a way to tell for sure. Like a number stamp on it somewhere, because the option sticker is still legible in the glove compartment. Or is there a way to look up the codes.

     If you can get a good enough pic of the SPID sticker in the glove box and post, we can help you out with all the options it came with.

[MyOldScottsdale23]

Trans code MXO

[bake74]

Trans code MXO

      One source:  (not any help)  http://www.nastyz28.com/gm-rpo-codes/rpo-m.php  ( MX0  82  88  MERCHANDISING OPTION ONLY-DO NOT CATALOG)
      Anouther source:        http://www.elcaminocentral.com/showthread.php?t=10763       (specifically about MXO RPO code)
      Anouther about MXO:       http://www.fullsizechevy.com/forum/general-discussion/technical-maintenance/244727-rpo-code-md8-mx0.html

 
   Here is a page to see the different pans on transmissions and where to find the serial #'s on them.     
    http://www.nastyz28.com/pictures/transpan.gif

 

[zieg85]

My 1985 C30 lists code MX1 which is the TH400

[MyOldScottsdale23]

The shift indicator above the column only shows 1,2,D. So I'm thinkin the TH400 is original.

[jaredts]

That just means they did the right thing and put in a shift indicator that matched the tranny they put in.  They're cheap and easy to install.