GMC vs. Chevy manual transmissions - The 1947 - Present Chevrolet & GMC Truck Message Board Network

69GMCLonghorn · 09-20-2008, 12:01 AM

I need some advice: I just bought a Gear Vendors to "bolt up" to my SM-465 transmission... or so I thought. I dug into things and discovered that GMC did not use the SM465 transmission; they used the New Process NP435, which was, for the most part, used in Fords and a few Dodges for about 20 years. Gear Vendors had never heard of that trans being in a GM product, and therefore COULDN'T SELL ME THE CORRECT ADAPTOR. As we speak, the unit is being boxed up and being sent back.

Has anyone else but me experienced this? Or did someone Mickey Mouse my truck prior to me owning it? Any info would be great.

**special-K** · 09-20-2008, 05:55 AM

I don`t know,but I`d talk to someone else at GV.The NP435 is all over the place and was used in Chevy/GMCs for years,especially post-72.

68C15 · 09-20-2008, 07:59 AM

mine had a 435, its still in the garage.

haysonj · 09-20-2008, 09:56 AM

Quote:

Originally Posted by 69GMCLonghorn

I need some advice: I just bought a Gear Vendors to "bolt up" to my SM-465 transmission... or so I thought. I dug into things and discovered that GMC did not use the SM465 transmission; they used the New Process NP435, which was, for the most part, used in Fords and a few Dodges for about 20 years. Gear Vendors had never heard of that trans being in a GM product, and therefore COULDN'T SELL ME THE CORRECT ADAPTOR. As we speak, the unit is being boxed up and being sent back.

Has anyone else but me experienced this? Or did someone Mickey Mouse my truck prior to me owning it? Any info would be great.

Check their website it shows both the 435 and 465 Iwould not think it would matter what the 435 was in its still the same trans.
http://www.gearvendors.com/agmanual.html

1969 GMC · 09-20-2008, 11:16 AM

Not all GMC's had it, my '69 came with a SM465.

The NP435 was an option, just like how the Sm465 was an option...and there are 2 versions of it: a wide (creeper gear) and close (no creeper) ratio.

edit: I know it's too late now, but for id purposes, the New process tranny has an aluminum top cover...99% of SM465's have cast iron top covers. easiest way to check.

D'Animal · 09-20-2008, 12:20 PM

Call or go to Advanced Adaptors in Paso Robles California.

They have adaptors for almost any combination you can think of.

Old Chevy Mech · 09-20-2008, 08:53 PM

Thats interesting...that explains why the 4 speed transmission out of my Dads 70 GMC pick up has an aluminum top cover! So its a new process. Any suggestions how to get this to adapt to a NP 205? It was in a 2WD so I wonder if the mainshaft is not going to allow this?
Is this a better transmission then the SM465?
Thanks!!
Frank

skchevota · 09-20-2008, 10:25 PM

Quote:

Originally Posted by Old Chevy Mech

Thats interesting...that explains why the 4 speed transmission out of my Dads 70 GMC pick up has an aluminum top cover! So its a new process. Any suggestions how to get this to adapt to a NP 205? It was in a 2WD so I wonder if the mainshaft is not going to allow this?
Is this a better transmission then the SM465?
Thanks!!
Frank

The out put shaft is diferant from the 2wd to 4x4. You would also need the tcase addapter, I would guess that that combo would be rare. Most of the 4x4 had the sm420 for the early years and then the sm465 in the later years.

Old Chevy Mech · 09-21-2008, 12:20 AM

I remember my dad always bragging about his tranny being a "camper special". He loved how the 3 & 4th gear were close so he could down shift while pulling a heavy load up hill and not lose 25mph. He told me how at 250k miles he had it rebuilt and the guy said it didnt need a rebuild, but did it anyway. Its sitting in my shed. I've got a NP205 with the adapter, so it sounds like I need a different output shaft to make it work. One day i'll get a chance to play with that setup.....

Frank

Blazer1970 · 09-21-2008, 06:56 AM

Quote:

Originally Posted by Old Chevy Mech

Thats interesting...that explains why the 4 speed transmission out of my Dads 70 GMC pick up has an aluminum top cover! So its a new process. Any suggestions how to get this to adapt to a NP 205? It was in a 2WD so I wonder if the mainshaft is not going to allow this?
Is this a better transmission then the SM465?
Thanks!!
Frank

GM never used the NP435 in any 4WD applications. You would have to use Dodge parts to do this.

**Bob B.** · 09-21-2008, 06:53 PM

Quote:

Originally Posted by Blazer1970

GM never used the NP435 in any 4WD applications. You would have to use Dodge parts to do this.

Correct! But be careful, some Dodge 4X4's with NP435's had divorced transfer cases.

factorystock · 09-21-2008, 10:08 PM

I guess Gear Vendors does not realize GMC used different manufactures of transmissions in their vehicles, just like Ford used Warner and New Process during these years.I think they are more knowledgeable in automatics.

1nice67chevy · 05-03-2009, 09:23 PM

can any one help me out i have a old 4 speed tarns with the reverse all the was to the left and down what kind is it

69GMCLonghorn · 05-04-2009, 10:34 AM

That is a Muncie SM420. It is the predecesor to the SM465, which was a little stronger. I think the SM420 had a lower granny gear, too. From what I know, it is a good tranny as long as you're not pushing a million HP through it.

09-20-2008, 12:01 AM	#1
69GMCLonghorn Registered User Join Date: Dec 2006 Location: Porter Ranch, CA Posts: 978	GMC vs. Chevy manual transmissions I need some advice: I just bought a Gear Vendors to "bolt up" to my SM-465 transmission... or so I thought. I dug into things and discovered that GMC did not use the SM465 transmission; they used the New Process NP435, which was, for the most part, used in Fords and a few Dodges for about 20 years. Gear Vendors had never heard of that trans being in a GM product, and therefore COULDN'T SELL ME THE CORRECT ADAPTOR. As we speak, the unit is being boxed up and being sent back. Has anyone else but me experienced this? Or did someone Mickey Mouse my truck prior to me owning it? Any info would be great.

09-20-2008, 05:55 AM	#2
special-K Special Order Join Date: Nov 2004 Location: Mt Airy, MD Posts: 85,851	Re: GMC vs. Chevy manual transmissions I don`t know,but I`d talk to someone else at GV.The NP435 is all over the place and was used in Chevy/GMCs for years,especially post-72. __________________ "BUILDING A BETTER WAY TO SERVE THE USA"......67/72......"The New Breed" GMC '67 C1500 Wideside Super Custom SWB: 327/M22/3.42 posi.........."The '67" (project) GMC '72 K2500 Wideside Sierra Custom Camper: 350/TH350/4.10 Power-Lok..."The '72" (rolling) Tim "Don't call me a redneck. I'm a rough cut country gentleman" R.I.P. ~ East Side Low Life ~ El Jay ~ 72BLUZ ~ Fasteddie69 ~ Ron586 ~ 67ChevyRedneck ~ Grumpy Old Man ~ Last edited by special-K; 09-21-2008 at 07:49 AM.

09-20-2008, 07:59 AM	#3
68C15 blood type; Retumbo Join Date: Jan 2004 Location: next to my reloading bench Posts: 10,269	Re: GMC vs. Chevy manual transmissions mine had a 435, its still in the garage.

09-20-2008, 11:16 AM	#5
1969 GMC Registered User Join Date: Feb 2003 Location: The Rubber City Posts: 5,498	Re: GMC vs. Chevy manual transmissions Not all GMC's had it, my '69 came with a SM465. The NP435 was an option, just like how the Sm465 was an option...and there are 2 versions of it: a wide (creeper gear) and close (no creeper) ratio. edit: I know it's too late now, but for id purposes, the New process tranny has an aluminum top cover...99% of SM465's have cast iron top covers. easiest way to check. __________________ 1969 GMC K2500 1996 Honda Accord 2007 Kawasaki KLR 650 Last edited by 1969 GMC; 09-20-2008 at 11:18 AM.

09-20-2008, 12:20 PM	#6
D'Animal Registered User Join Date: Aug 2008 Location: Exeter, Ca Posts: 100	Re: GMC vs. Chevy manual transmissions Call or go to Advanced Adaptors in Paso Robles California. They have adaptors for almost any combination you can think of.

09-20-2008, 08:53 PM	#7
Old Chevy Mech Keepin it runnin! Join Date: Oct 2007 Location: Deep River, CT Posts: 1,036	Re: GMC vs. Chevy manual transmissions Thats interesting...that explains why the 4 speed transmission out of my Dads 70 GMC pick up has an aluminum top cover! So its a new process. Any suggestions how to get this to adapt to a NP 205? It was in a 2WD so I wonder if the mainshaft is not going to allow this? Is this a better transmission then the SM465? Thanks!! Frank __________________ 1970 K-5 4X4 Blazer 1970 K-20 4X4 Long Bed "Liberty Means Responsibility, that is why most men dread it"

09-21-2008, 12:20 AM	#9
Old Chevy Mech Keepin it runnin! Join Date: Oct 2007 Location: Deep River, CT Posts: 1,036	Re: GMC vs. Chevy manual transmissions I remember my dad always bragging about his tranny being a "camper special". He loved how the 3 & 4th gear were close so he could down shift while pulling a heavy load up hill and not lose 25mph. He told me how at 250k miles he had it rebuilt and the guy said it didnt need a rebuild, but did it anyway. Its sitting in my shed. I've got a NP205 with the adapter, so it sounds like I need a different output shaft to make it work. One day i'll get a chance to play with that setup..... Frank __________________ 1970 K-5 4X4 Blazer 1970 K-20 4X4 Long Bed "Liberty Means Responsibility, that is why most men dread it"

09-21-2008, 10:08 PM	#12
factorystock Registered User Join Date: Feb 2007 Location: west coast Posts: 3,396	Re: GMC vs. Chevy manual transmissions I guess Gear Vendors does not realize GMC used different manufactures of transmissions in their vehicles, just like Ford used Warner and New Process during these years.I think they are more knowledgeable in automatics.

05-03-2009, 09:23 PM	#13
1nice67chevy Registered User Join Date: Jun 2008 Location: Glendive MT Posts: 15	Re: GMC vs. Chevy manual transmissions can any one help me out i have a old 4 speed tarns with the reverse all the was to the left and down what kind is it __________________ KEEP ON TRUCKIN!!!

05-04-2009, 10:34 AM	#14
69GMCLonghorn Registered User Join Date: Dec 2006 Location: Porter Ranch, CA Posts: 978	Re: GMC vs. Chevy manual transmissions That is a Muncie SM420. It is the predecesor to the SM465, which was a little stronger. I think the SM420 had a lower granny gear, too. From what I know, it is a good tranny as long as you're not pushing a million HP through it.

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