# M 12 6 speed



## UdnUdnGTO (Jan 30, 2006)

Certainly I am slow, but I just ran into some langauge under the hood I do not understand. I read others talking about M6, uner the hood, I have a M12. So what is the difference, if any?


----------



## Ninjured (Apr 28, 2006)

not to confuse you more but we have a tremec t-56 transmission
http://www.tremec.com/English/products/T-56.asp#Car

the model t-56 we have is the m12 (not to be confused with the MM6, MZ6 or M10)
read up...
http://www.cadillacfaq.com/faq/answers/pdf/t56-06.pdf

most put m6 to signify 6-speed manual cause saying I drive a GTO with the m12 can be a little confusing


----------



## bg2m8o (Jul 25, 2006)

M6 is the colloquial term for Manual 6 speed. The M12 you see on the build tag is the RPO (regular production order) code for the trans. All GM factory equipment is coded this way.

Some common ones include: Z28, Z51 (Z codes are suspension, as well as some F codes)

Engines are almost always preceeded by L, Hence LS2, LS1, LT1, LT5. etc

Axles are G (G80 is almost universal for a LSD type dif) Other axle codes are present too, usually denoting ratios.

Trans codes are M. M12 for the Tremec, The 4 speed autos were almost always MXO, but I think the Goat is different M21, M22's were the rock crusher 4 speeds back in the day.

Looking at the SPI tag in the trunk of the goat bears this out. This tag is often in the glove box of GM cars and is also often confused with the build sheet which it is not. The Goat is indeed coded with LS2, G80, M12 etc.


----------



## UdnUdnGTO (Jan 30, 2006)

arty: Wow, thanks for the explanation.

That works.


----------



## bg2m8o (Jul 25, 2006)

You're Welcome! I tend to have a veritable plethora of useless knowledge on such things. Wish I could find my build sheet! Maybe they don' do 'em in Oz.


----------

