by deeredr » Mon Aug 02, 2010 5:40 pm
Matt is also correct concerning the M vs AM prefix.
In the Deere parts nomenclature, single letter prefixes signify a bare part. Once anything is added to a part, for example a bushing or a bolt or a clip then the part # has an "A" attached to it signifying a part assembly.
In the good old days, the letter prefix meant more than they do now.
R and AR were Waterloo factory sourced, in this case tractor parts
E and AE were Ottumway factory sourced, in this case hay tool parts.
H and A were Harvester factory sourced, in this case combine or crop cutting parts.
and so on.
M and AM are Horicon factory sourced. However, recall that long long before lawn tractors and snowmobiles came on the scene, Horicon was a grain drill factory. Deere chose to convert it from drills to producing their new line of lawn equipment. Hence, many older M and AM parts have nothing to do with Deere's Consumer Products. As a very general rule, if the part #'s a low five digit or a four digit then it's likely not a lawn tractor or snowmobile part. To add further confusion, Deere's Dubuque factory built tractors, such as the model M, 40,320,330,420 and 430 all carried M and AM part #'s with, again, being mostly lower 5 digit or 4 digit part #'s. These Dubuque part #'s later were changed over to T and AT prefixes when the new Industrial products began to emerge.
Also factor in that Deere's bicycles as well as chain saws carried M and AM part #'s that look to be correct for lawn tractors or snowmobiles and you can see there's no hard and fast rule. You have to do your research.
Ok, lesson over
Greg
30 year JD partsman