From a 700R to a Muncie M21 or M22 or a Borg Warner T-10

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Texas Agman

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I've got a 85 C10 Silverado that is very solid mechanically and cosmetically, but my problem is the 700R tranny. I have spent a fortune over the last 22 years in tranny repairs so now I am considering an change-over to a Muncie M21 or M22, or perhaps a Borg Warner T-10. Have any of you done a project like this one? If you have, please give me an idea of what I am looking at on parts availability, etc. My truck is a ranch truck, so the 4 speed would work great for the job that the truck does. Thanks for your help!
 

SquareRoot

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Why not a NV4500? Best manual ever made for trucks. Plus being an 85 you can bolt in a factory hydraulic clutch.
 

Josh Helm

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Yeah I did the nv3500 but for heavy duty the 4500 would be my vote too
 

RoryH19

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The M21 or M22 are more for muscle cars and only have 4 forward.

The SM465 was a factory option but an upgrade would be the nv4500 with 5 forward.
 

idahovette

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I don't think any of your choices will suit you for a "farm" truck. First gear is gonna be pretty high for around the farm depending on axle gearing, like @RoryH19 said they are more for the street unless you gotta "farm truck" like the Outlaws
 

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Things to think about,the munchies are bad about wearing the counter shaft bores out in the case out, and they are all old enough that unless you spend a fortune on a good one your going to spend a fortune fixing one.So for 22 years you've been driving it with an auto and happy other than tearing up 700r4s. The simplest fix for a farm truck would be a longshaft th350, it will almost install itself in there.A th400 is a little stronger but not as easy as th350 swap. If it's truly a farm truck you don't need the OD. If you want OD, a 4l80 is tough,but not as easy as a th350/400 swap. You can get the shift controller and transmission harness out of a diesel with 4l80, so you don't have to by an expensive shift controller. But think about this the th350 swap you unbolt your 700,you bolt in the 350, add a vacuum line for the modulator, move the crossmember to line up with the mount, that's it. 2 modifications, your driveshaft even works.
 
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Texas Agman

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Thanks for your quick responses. Will digest all of the submitted data and move forward.
 

mcarlo86

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What has been causing the 700R4 troubles? Do you tow a lot? Just curious.
 

dsteelejr

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My vote goes for the SM465.

I second that. I have one in my square and my uncle, who is retired mechanic, has one in his square. He swears they're bullet proof and running them low on oil is about the only way to destroy them. Would be a great tranny for a ranch truck, with a 6.55 ratio granny low and no overdrive.
 

DoubleDingo

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I also vote sm465
 

Texas Agman

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Thanks for your suggestions, guys, and I am doing research as we speak. And, mcarlo86, I have done lots of towing...in 3rd gear. I appreciate your input from the forum.
 

75Monza

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First off, what gears do you run?
 

dsteelejr

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Thanks for your suggestions, guys, and I am doing research as we speak. And, mcarlo86, I have done lots of towing...in 3rd gear. I appreciate your input from the forum.
I am not too familiar with the M21 and M22, but just a quick search for the gear ratios show that they are geared pretty high. Those are the last manual transmissions you’d want in a truck, especially for ranch use. Those transmission were made for performance cars of the 60s and 70s with 4.10 or 4.56 gears in the rear end. The SM465 (some literature mentions it as a CH465) is a truck transmission with 6.55 granny low, 3.58 first, 1.70 second and 1:1 for top gear. Compare to the M21 and M22 in the image.
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