All you need to know about the Muncie SM465

Even if you are not a fan of manuals, you've very likely heard of the SM465, a legendary manual transmission. Let's dive into it.

BRIEF INTRO

The Muncie SM465 was built by GM and offered from 1968 to 1991, replacing the Muncie SM420. Although it was officially replaced by the NV4500 in 1992, it has been spotted in Topkicks/Kodiaks after that year; however, no official documentation of this existence exists. The SM465 was mostly available in 1/2 ton to 1-ton trucks throughout its life and was known for being incredibly bulletproof and reliable.

GEAR RATIOS

• First - 6.55:1

• Second - 3.58:1

• Third - 1.70:1

• Fourth - 1.00:1

• Reverse - 6.09:1

GRANNY LOW AND DIRECT DRIVE

Looking at the gear ratios, we can see 1st is incredibly low, which is one of the big reasons the SM465 became so popular. Fourth is a direct drive, which allows predictable torque, less stress on parts, and was much better at towing.

WHY IS IT CALLED THE MUNCIE SM465?

It stands for "Synchro-Mesh 465." 465 was just a designator for GM at the time. "Muncie" comes from Muncie, Indiana, where it was built.

SYNCED UP

2nd, 3rd, and 4th are all synchronized, allowing for ultra-smooth shifting.

CAST IRON

Entire cast iron case, making the Muncie SM465 weigh roughly 175lbs dry.

MODABILITY

Some modders have paired it with an NP203 range box, then an NP205 transfer case for even lower gearing, typically for rock crawling purposes.

Cheap adapters have made them start showing up in Toyotas, Jeeps, Fords, and even Dodges.

The extremely low 1st gear makes it a coveted item for some off-road enthusiasts and people who like to continue towing with their classics.

Some modders have put it behind 500hp rigs with no major failures.

CONS

1. It weighs 175lbs dry.

2. Not a fast shifter.

3. No 1st gear synchronization.