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Old 08-02-2009, 10:02 PM   #1
Eturnit3
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Question 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!!
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Old 08-03-2009, 06:22 PM   #2
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Re: 3 speed manual tranny questions.

It's probably the SM465 if is has 3 speeds and a low, unsyncronized granny gear.
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Old 08-03-2009, 08:23 PM   #3
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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.
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Old 08-04-2009, 10:01 AM   #4
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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...)
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Old 08-04-2009, 06:23 PM   #5
Eturnit3
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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
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Old 08-04-2009, 06:24 PM   #6
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Re: 3 speed manual tranny questions.

Quote:
Originally Posted by xbanone View Post
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!!
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Old 08-05-2009, 01:24 PM   #7
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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.
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Old 08-06-2009, 07:35 AM   #8
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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.
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