Manual transmission options

Recently joined this very cool site do to the fact I bought an 1981 K10. It's a little different in the front, it has a 1991 front end. Was never in a accident or anything like that, the previous owner just liked the look of the four little square headlights, so he changed it. Starting to grow on me too so I will probably just leave it that way.
Anyway it's set up for the offroad without a doubt. Has the original and rebuilt 350. Has the factory SM465 and here's the kicker, the front and rear gears were changed to a 4-1 ratio. Damn thing will go up a brick wall. That would have been great when I was younger but now days I just want to use it mainly to get into hard to reach fishing spots and for the snowy country to ski. Problem is i can't even drive it anywhere but the city do to gearing. Our highways are listed at 75 mph and mostly above that. This truck would be a hazard out there.
I was looking into a Tremec T56 but I guess you can only use them on a divorced Transfer case. That's not the case on my truck. Has anyone been down this road before and able to advise me? Don't really want to change out the pumpkins but it might be inevitable. All comments are welcome and appreciated.

Welcome from Texas. I don't know **** about this but, I'm sure someone else does. Got any pics of it?

Wouldn't be cheap but if it were me. I'd look into adding a gear vendors unit off what you already have.

Or.

Also not cheap. Swap in a nv4500/nv3500. Give high-impact.net a look for complete swap kits. (being a k10 a nv3500 should live well enough I'd think)

NV4500 swap is the hot ticket. Being an 81 I think you still have the Z bar linkage clutch. Swap to the Hydro Clutch pedals and then go from there. It's a bit costly but well worth it. You have the better of all the worlds. Low Crawl Ratio just like you have now, much better freeway cruising, and all the strength you'd need.

Dutch Rutter said:

Wouldn't be cheap but if it were me. I'd look into adding a gear vendors unit off what you already have.

Or.

Also not cheap. Swap in a nv4500/nv3500. Give high-impact.net a look for complete swap kits. (being a k10 a nv3500 should live well enough I'd think)

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At Dutch suggested, the NV3500 is also an option. What might make that one a bit cheaper to convert to is, the Transfer case adapter is actually already built into the trans housing and the Aluminun Case Round pattern Transfer cases like the NP208 and NP241C and bolted direct to the transmission housing round pattern ring.

I'm running a NV4500 with 3.73 rears and 265/75R16 tires. Easily cruise at 70-75. If u r running a taller tire your current ratio would work great with it.

BKING33 said:

I'm running a NV4500 with 3.73 rears and 265/75R16 tires. Easily cruise at 70-75. If u r running a taller tire your current ratio would work great with it.

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If I may jump in and ask, what is a NV4500 trans?

It's a 5 speed overdrive trans from mids 90s and up. Usually in HD trucks.

I'll add, it's not only a 5 speed, but it's also got the granny 1st gear too. So with the granny gear 1st and the 5th gear overdrive you have the better of all worlds. But most do drive it like a 4 speed with the tallest gear being overdrive and only use 1st or granny low as needed. It's strong one. IIRC, you're preference should be a 95 or newer one. They're also commonly used in Dodges but then you get into different shaft lenghts and clutch plates to fit Dodge, so it's best to find a GM unit, but if you're out looking for one, just know that Dodge used them too so don't let someone sell you a Dodge NV4500 that'll need conversions done. BTW, NV is for New Venture which is the name of the company just like Muncie, Saginaw, Dana, Borg Warner, or Tremec etc.

HotRodPC said:

I'll add, it's not only a 5 speed, but it's also got the granny 1st gear too. So with the granny gear 1st and the 5th gear overdrive you have the better of all worlds. But most do drive it like a 4 speed with the tallest gear being overdrive and only use 1st or granny low as needed. It's strong one. IIRC, you're preference should be a 95 or newer one. They're also commonly used in Dodges but then you get into different shaft lenghts and clutch plates to fit Dodge, so it's best to find a GM unit, but if you're out looking for one, just know that Dodge used them too so don't let someone sell you a Dodge NV4500 that'll need conversions done. BTW, NV is for New Venture which is the name of the company just like Muncie, Saginaw, Dana, Borg Warner, or Tremec etc.

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The real question is what does CH in CH465 mean!?

AuroraGirl said:

The real question is what does CH in CH465 mean!?

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Where the hell did you see this at? Maybe it means Chineese 465??? I know SM465 means Sychro Mesh and is a Muncie unit.

GM service data from the time references it as CH465

AuroraGirl said:

GM service data from the time references it as CH465

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Had to google it since curiousity got to me. Here's the #1 post.

The SM465 is an outstanding, heavy-duty truck transmission designed and used in ½, 3/4 and 1+ ton trucks. ... The "SM" in the transmission's designation stands for Synchro-Mesh, in the tradition of other GM gearboxes. It is also referred to as the CH-465 or CH465 by factory literature.

GM is always trying to be different unecessarily! I feel they could have just picked one

Dutch Rutter said:

Wouldn't be cheap but if it were me. I'd look into adding a gear vendors unit off what you already have.

Or.

Also not cheap. Swap in a nv4500/nv3500. Give high-impact.net a look for complete swap kits. (being a k10 a nv3500 should live well enough I'd think)

Click to expand...

HotRodPC said:

NV4500 swap is the hot ticket. Being an 81 I think you still have the Z bar linkage clutch. Swap to the Hydro Clutch pedals and then go from there. It's a bit costly but well worth it. You have the better of all the worlds. Low Crawl Ratio just like you have now, much better freeway cruising, and all the strength you'd need.

Click to expand...

They beat me to it