Tractor Repair: Case IH 7140, hydraulic couplers, series tractors

Question
I just bought a CIH 7140. When I made the deal, the dealer told me it is a 1993 model. After I checked the serial number I found out it is a 1988 model. Are there many differences between the two year models?

Answer
 The 7100 series was produced from 1987 to 1993 and had only a few slight changes during production until the 7200 series came along which had over 60 changes to the original design of the 7100 series.  The very early 7100 series tractors had product updates that were supposed to be performed by dealers on every unit such as replacing the remote hydraulic couplers, changing the steel oil supply pipe for the hitch to a flexible hose, installing an inline fuel filter between the tank and the lift pump, and replacing the hitch rockshaft potentiometer bracket and linkage.  This update would make these early 7100 tractors current with the changes that were made during production.  So there were not many differences between the two year models.  All 7100 series tractors were pretty much the same until the 7200 series made some big changes.