Considering the million of products that serial number might be for...try taking it to your local JOHN DEERe dealer along with the model number and I'm sure he can help tell you everything you want to know.
What I have done in the past is call or go to my local John Deere dealer and have them run a national VIN# check for me and it will come up with your correct year and all the characteristics in your VIN#.
According to Tractor Data.com your Model 40 was manufactured in 1954.
Tractordata.com indicates 1990
Write down the serial number and take it to your John Deere dealer.
Your John Deer is a 1992 per John Deere serial number list provided by manufacture.
I have a F911 john deere front mow with a serial number of MOF911X110134. Can you tell the year of manufacture?
Final serial number: 7330358
Where is the serial# located on a John Deere 336 square baler
what year is my John Deere 450B Dozer with serial number 110863T
morx73x477787
Your John Deere 322, serial number M00322x596318 is a 1989 model year.
What year is my John Deere 14T hay baler with a serial number of 38497?Read more: What_year_is_my_John_Deere_14T_hay_baler_with_a_serial_number_of_28517
1989
1978
on the frame in the front of the tractor