GM & CHEVY SM465 4 SPEEDS 1968 & UP:
This transmission can be identified by a case length of 12". The casting numbers on the case should be GM465452,
6273212 or 3901127. The top shift cover casting number should be GM3901131. The P.T.O. opening is available
on both sides of the main case. This transmission has a non-synchro first gear. The gear ratios for this transmission
are as follows:
- First Gear 6.46
- Second Gear 3.58
- Third Gear 1.70
- Fourth Gear Direct
- Reverse 6.09
We highly recommend using a manual transmission shop for installing the output shaft in the transmission.
If you attempt the installation on the SM465 shaft on your own, please be careful with the sleeves as they are a press
fit and they can shatter during installation. The sleeves are a very close tolerance. To help in the assembly of these
sleeves, you can heat them in a oven (250 degrees for 10 minutes) which will increase the size of the bushing making
it easier to install. (Be sure to use eye and face protection when pressing, and leather gloves when handling the heated
You will need to retain the stock rear bearing, thrust washer and locking nut from your old output shaft. On GM 2WD
transmission, a new washer and nut must be purchased from a transmission shop.
This output shaft is a universal length, it may require to be shorted depending on the adapter casting that you are using.
If used with an Atlas transfer case please refer to the input section of the Atlas manual to verify the stick out length.
Do not force the transmission and transfer case together.