JD model numeers

JD Seller or others. Is there any rhyme or reason to the JD tractor model numbering system? Is there anyplace to read what is what?

Hey JD you know as much as I know that the tractor makers in this world only do this so they can sell tractors. Here is a good example if the maker of tractors did not change them you would not buy a new one(right). I have the Rust book, John Deere tractor data book, and the other book that they say is to be great (Blue book). When you look at them all they look like my enternet prices.Except for the John Deere data book. that one is interesting because it covers facts and it goes to 1930 to the 1960. Good book.I also buy old tractor blue books from people who quiet selling tractors.

No rhyme or reason to the letter series. L is the smallest, R the largest, with a bunch of letters in between, in no particular order.

2 digits- 40 (smallest) to 80 (largest), in order.

3 digits- stuck a 2 between the 2 digit number, to indicate 2nd series (with improvments over the 2 digit). Still in order, with a 320 thrown in at the bottom. Next series changed the 2 to a 3.

4 digits- started out OK- 1010 through 5010 (was there a 6010?), in size order. Later improved version, third digit changed from 1 to 2, so 1020 through 5020, still in order.

Then they dropped the 1, 3, and 5 first digits, so had 2040, 2240, etc. and 4030, 4230, etc.- first digit was the basic size- 2 (smaller) or 4 (larger), 2nd digit was the size within the series (2040, 2240, 2440, etc), and 3rd digit was the chronological indicator (3 or 4, IIRC).

Then they seemed to lose their way. Started duplicating numbers as early as the 70's -came out with a small 3 cylinder utility tractor numbered 820 and 830, which had no relationship to the earlier big 820 and 830 two cylinders. People started asking "2 or 3 cylinder" when someone would refer to those numbers. I kind of lost track after that (I limit my attention to those models that I might, in my wildest dreams, be able to afford). By the time I bought a 4010 in 2005, it was pretty much chaos- all kinds of number duplication. My 2005 4010 compact utility of 18.5 horsepower only resembles its 1961 4010, 90+ horsepower predecessor in that they are both a pleasant green and yellow color.

JD Seller is pretty familiar with later model numbers- would be interested to see if there was any pattern to them.

Thanks, Now I see why I am confused.

To make it confusing JD engineers had to start duplicating some model numbers but the certainly didn't duplicate the famous "4020". Too make it even more confusing they make several different variations of the same horsepower just with more options(economy to luxury).

I think they have one of those lotto machines with the ping pong balls with numbers on it. Need a new model number turn on the machine ! And just like the lotto sometimes you get duplicates.
This is the only way I can explain it !