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73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: MyOldScottsdale23 on February 12, 2012, 10:14:22 pm

Title: TH 400 Original?
Post by: MyOldScottsdale23 on February 12, 2012, 10:14:22 pm: 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?
Title: Re: TH 400 Original?
Post by: Blazin on February 12, 2012, 10:21:20 pm: 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.
Title: Re: TH 400 Original?
Post by: MyOldScottsdale23 on February 13, 2012, 04:15:41 am: 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.
Title: Re: TH 400 Original?
Post by: zieg85 on February 13, 2012, 06:17:22 am: With the codes we should be able to come up with an answer.
Title: Re: TH 400 Original?
Post by: bake74 on February 13, 2012, 06:46:29 am: Quote from: MyOldScottsdale23 on February 13, 2012, 04:15:41 am
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.
Title: Re: TH 400 Original?
Post by: MyOldScottsdale23 on February 13, 2012, 08:09:56 am: Trans code MXO
Title: Re: TH 400 Original?
Post by: bake74 on February 13, 2012, 09:25:56 am: Quote from: MyOldScottsdale23 on February 13, 2012, 08:09:56 am
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 (http://www.nastyz28.com/pictures/transpan.gif)
Title: Re: TH 400 Original?
Post by: zieg85 on February 13, 2012, 04:14:02 pm: My 1985 C30 lists code MX1 which is the TH400
Title: Re: TH 400 Original?
Post by: MyOldScottsdale23 on February 14, 2012, 03:54:17 pm: The shift indicator above the column only shows 1,2,D. So I'm thinkin the TH400 is original.
Title: Re: TH 400 Original?
Post by: jaredts on February 14, 2012, 07:03:59 pm: 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.