3 speed manual tranny questions. - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Eturnit3 · 08-02-2009, 10:02 PM

I have a 72 GMC K15 350 3spd np205. My questions are, what is the tranny called? Is there more than one model? What maintenance is required if any? Does it require any fluid replacements? Is it fairly strong? Ive been beating this thing for about 8 years and its still going strong.. I have had some linkage issues, replaced a clutch, the usual. Ive been planning on swapping in a th350 but this has been so good to me thus far. Thanks for any input!!

TonyJohnson · 08-03-2009, 06:22 PM

It's probably the SM465 if is has 3 speeds and a low, unsyncronized granny gear.

xbanone · 08-03-2009, 08:23 PM

The Sm465 is the 4 speed with the very low first gear,

It sounds like you have the Saganaw Sm326. I had one in my '76 and it lasted 33 years and over 200k miles and was still going strong when I pulled it for a 4 speed swap last month. It is a reasonably strong trans when behind a stocksih engine. Just don't abuse it and you should be fine. As far as maintenance goes, just some good gear lube and make sure all your seals are good and not leaking and you should have plenty of trouble free miles ahead of you.

TonyJohnson · 08-04-2009, 10:01 AM

Many of the shift knobs of the SM465 are L-1-2-3, so they get mistaken for 3 speeds (which they effectively are, IMO...)

Eturnit3 · 08-04-2009, 06:23 PM

its whatever a 3 on the tree is.. there is no 4th gear, the shift pattern is an "H" top left is reverse, lower left is 1st, upper right 2nd, lower right 3rd
R 2
H
1 3

deff. not a sm465

Eturnit3 · 08-04-2009, 06:24 PM

Quote:

Originally Posted by xbanone

The Sm465 is the 4 speed with the very low first gear,

It sounds like you have the Saganaw Sm326. I had one in my '76 and it lasted 33 years and over 200k miles and was still going strong when I pulled it for a 4 speed swap last month. It is a reasonably strong trans when behind a stocksih engine. Just don't abuse it and you should be fine. As far as maintenance goes, just some good gear lube and make sure all your seals are good and not leaking and you should have plenty of trouble free miles ahead of you.

Thank you Sir, you are a gentleman and a scholar!!

xbanone · 08-05-2009, 01:24 PM

Thanks "E"

The big hint it wasnt a SM465 is the fact that you said you have linkage problems. the 465 is top load and has no external linkage.

A K15 that is still 3 on the tree 4x4 is a rarity these days. I wrestled with that for a while before I started the 4 speed swap.

The big advantages to the SM326 is the lightweight, ease of shifting and relatively close ratio.

**special-K** · 08-06-2009, 07:35 AM

The only disadvantage is the high 1st and reverse.But,it works and will give you what you ask of it if you respect it.My`71 Custom Deluxe K/10 swb is a 307/3spd.I considered restoring it to stock/original just because it would be kinda unique.Blazers used the light duty Model 20 transfer case with the 3spd.

08-02-2009, 10:02 PM	#1
Eturnit3 Bloodied Knuckles Join Date: Jan 2009 Location: Grass Valley CA Posts: 273	3 speed manual tranny questions. I have a 72 GMC K15 350 3spd np205. My questions are, what is the tranny called? Is there more than one model? What maintenance is required if any? Does it require any fluid replacements? Is it fairly strong? Ive been beating this thing for about 8 years and its still going strong.. I have had some linkage issues, replaced a clutch, the usual. Ive been planning on swapping in a th350 but this has been so good to me thus far. Thanks for any input!!

08-03-2009, 06:22 PM	#2
TonyJohnson Registered User Join Date: Mar 2003 Location: Cheboygan, MI Posts: 998	Re: 3 speed manual tranny questions. It's probably the SM465 if is has 3 speeds and a low, unsyncronized granny gear. __________________ Tony Johnson -- '71 Blazer w/L-31 Vortec 350, SM465, NP205, performer intake, edelbrock 1406, HEI, 4" lift, Boyd EFI tank, Vintage A/C My Blazer --

08-03-2009, 08:23 PM	#3
xbanone Registered User Join Date: Oct 2008 Location: WV Posts: 209	Re: 3 speed manual tranny questions. The Sm465 is the 4 speed with the very low first gear, It sounds like you have the Saganaw Sm326. I had one in my '76 and it lasted 33 years and over 200k miles and was still going strong when I pulled it for a 4 speed swap last month. It is a reasonably strong trans when behind a stocksih engine. Just don't abuse it and you should be fine. As far as maintenance goes, just some good gear lube and make sure all your seals are good and not leaking and you should have plenty of trouble free miles ahead of you. __________________ 1976 K15 Short/Step 1981 C10 short/wide 1994 K1500 ECSB

08-04-2009, 10:01 AM	#4
TonyJohnson Registered User Join Date: Mar 2003 Location: Cheboygan, MI Posts: 998	Re: 3 speed manual tranny questions. Many of the shift knobs of the SM465 are L-1-2-3, so they get mistaken for 3 speeds (which they effectively are, IMO...) __________________ Tony Johnson -- '71 Blazer w/L-31 Vortec 350, SM465, NP205, performer intake, edelbrock 1406, HEI, 4" lift, Boyd EFI tank, Vintage A/C My Blazer --

08-04-2009, 06:23 PM	#5
Eturnit3 Bloodied Knuckles Join Date: Jan 2009 Location: Grass Valley CA Posts: 273	Re: 3 speed manual tranny questions. its whatever a 3 on the tree is.. there is no 4th gear, the shift pattern is an "H" top left is reverse, lower left is 1st, upper right 2nd, lower right 3rd R 2 H 1 3 deff. not a sm465

08-05-2009, 01:24 PM	#7
xbanone Registered User Join Date: Oct 2008 Location: WV Posts: 209	Re: 3 speed manual tranny questions. Thanks "E" The big hint it wasnt a SM465 is the fact that you said you have linkage problems. the 465 is top load and has no external linkage. A K15 that is still 3 on the tree 4x4 is a rarity these days. I wrestled with that for a while before I started the 4 speed swap. The big advantages to the SM326 is the lightweight, ease of shifting and relatively close ratio. __________________ 1976 K15 Short/Step 1981 C10 short/wide 1994 K1500 ECSB

08-06-2009, 07:35 AM	#8
special-K Special Order Join Date: Nov 2004 Location: Mt Airy, MD Posts: 85,851	Re: 3 speed manual tranny questions. The only disadvantage is the high 1st and reverse.But,it works and will give you what you ask of it if you respect it.My`71 Custom Deluxe K/10 swb is a 307/3spd.I considered restoring it to stock/original just because it would be kinda unique.Blazers used the light duty Model 20 transfer case with the 3spd. __________________ "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 ~



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