How do I identify my Muncie M21?
There is another way to quickly identify Muncie transmissions. All Muncie transmissions have a ring groove on the input shaft and counter gear. These grooves were cut into the input shaft so the Muncie assembly line worker could easily identify which input shaft should be installed in a particular unit.
Where is the serial number on a Muncie transmission?
TRANSMISSION PRODUCTION CODE NUMBER LOCATION 1963 & 1964 Muncie Transmission: Passenger and Corvette models stamped on the left side of case rear of side cover.
How do I know if I have a Muncie M22?
How to Identify a M22 Rock Crusher
- Check the casting number, the production year and the gear ratios on the aluminum serial number plate attached to the transmission box.
- Count the input shaft teeth to find out the make of the transmission.
- Count the number of splines in the transmission.
Where are the casting numbers on a Muncie transmission?
All Muncie transmission cases are made of aluminum, and the identifying casting numbers are prominently stamped in the passenger side of the transmission case. Muncie Four Speed casting numbers identify all aluminum Muncie main cases: 3831704 – 1963 only 3851325 – 1964-’65 3885010 – 1965-’67 3925660 – 1968-’70 3925661 – 1971-’74
Where is the casting date on a Muncie 4 speed?
Many Muncie 4-speed maincases, extension housings, and sidecovers have a casting date code. On maincases, the code is usually found on the passenger side of the case below the casting number.
How can I tell if my Muncie has a m21 or M22?
As mentioned previously, we know that the Muncie came with several ratios. Because main cases are often swapped rather than being repaired, the best way to determine if you have an M20, M21, or M22 is to simply look at the gears. Without removing the sidecover you can look at the input shaft and check for identification grooves cut into the spline.
Where is the extension housing code on a Muncie transmission?
The extension housing code is usually within a few inches of the casting number also on the passenger side. Muncie casting date codes are very different from other transmission manufacturers. The code consists of two circles, both 1/2-inch in diameter and divided in half. One circle is called the date marker, the other the status marker.
How can I tell if my Muncie transmission is m21 or M22?
Take the side cover off & count the number of teeth on the input shaft. Also check the angle of the gear teeth. With this information you will be able to tell if you have an M20, M21 or M22 gearset.
All Muncie transmission cases are made of aluminum, and the identifying casting numbers are prominently stamped in the passenger side of the transmission case. Muncie Four Speed casting numbers identify all aluminum Muncie main cases: 3831704 – 1963 only 3851325 – 1964-’65 3885010 – 1965-’67 3925660 – 1968-’70 3925661 – 1971-’74
What was the case number on the Muncie M22?
(3) Colvin’s “by the numbers” book notes that Muncie data shows 1968 and 1969 M22 transmissions received main case #3925661. All documented M22 transmissions have the #3925660 main case. It is unclear why there is the discrepancy.
When did Muncie start using close ratio M21?
From 1963 to 1965 the close ratio M21 was ordered under the M20 RPO code and the factory decided whether to install a wide ratio M20 or close ratio M21 depending on the rear axle ratio specified. From 1966 on, the customer could decide the transmission selection.