Saginaw or Borg Warner? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

strick9c10 · 05-12-2009, 04:56 PM

I have the opportunity to purchase a parts truck for my '79 C-10 project. I haven't seen the truck in person yet, although the owner has snapped a few pictures & sent over email. It has a 4 speed in it & he says the transmission has an RPO code of MM4. Does this code signify a Saginaw or a Borg Warner? It's the original unit behind the original 350 4bbl. The parts truck is also a 1979.

I've researched on line & can't find any code info... only that it's a 4 speed. I have info on visual identification, but I'm not there to verify.

Any help would be great. Thanks!!

sierra4x4 · 05-12-2009, 10:00 PM

If it is original then it will be a muncie sm465 which is a truck only trans and is nothing like a saginaw or borg warner car trans. The sm465 has a granny 1st gear.

strick9c10 · 05-13-2009, 07:37 AM

Thanks for the info! Even though this is my 17th "project" vehicle I'm working on, this is my 1st truck project / restification... still have all that "car stuff" in my head as well as in my books & notes.
The truck was originally a straight 6, but when I purchased it, it already had a modified 355 in it with a Saginaw 3 speed using the original column shifter set up. A little weird, but I guess one of the previous owners was just working with what he had.

05-12-2009, 04:56 PM	#1
strick9c10 Registered User Join Date: Mar 2009 Location: Mid-Coast Maine Posts: 33	Saginaw or Borg Warner? I have the opportunity to purchase a parts truck for my '79 C-10 project. I haven't seen the truck in person yet, although the owner has snapped a few pictures & sent over email. It has a 4 speed in it & he says the transmission has an RPO code of MM4. Does this code signify a Saginaw or a Borg Warner? It's the original unit behind the original 350 4bbl. The parts truck is also a 1979. I've researched on line & can't find any code info... only that it's a 4 speed. I have info on visual identification, but I'm not there to verify. Any help would be great. Thanks!! Last edited by strick9c10; 05-12-2009 at 04:57 PM. Reason: added info

05-12-2009, 10:00 PM	#2
sierra4x4 Registered User Join Date: Jan 2009 Location: Canada Posts: 308	Re: Saginaw or Borg Warner? If it is original then it will be a muncie sm465 which is a truck only trans and is nothing like a saginaw or borg warner car trans. The sm465 has a granny 1st gear.

05-13-2009, 07:37 AM	#3
strick9c10 Registered User Join Date: Mar 2009 Location: Mid-Coast Maine Posts: 33	Saginaw or Borg Warner? Thanks for the info! Even though this is my 17th "project" vehicle I'm working on, this is my 1st truck project / restification... still have all that "car stuff" in my head as well as in my books & notes. The truck was originally a straight 6, but when I purchased it, it already had a modified 355 in it with a Saginaw 3 speed using the original column shifter set up. A little weird, but I guess one of the previous owners was just working with what he had.



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