What model has run the longest basically unchanged?
i wanna say the skytrak 6036 model????? just guessing but they have been around quite a while. Also maybe the lull 6k highlander???? You would know more about that one though.
I think gradall have not much change over the years from basic design. Even a Lull 1054-C has a 13 year run unchanged. Seems like yesterday. 644 has been around a long time and was a great seller. I forgot what year it came out may be 1978 to 1995
The original Loed 552/554 machines were introduced about 1974 and were in production until the mid 90's when Gradall finally quit building them. They were never big sellers, but were a beast.