4140 is the same as 4000 SU. 4000 is the basic model, Ford made different variations, derivatives, of the basic model.
Below I gathered some derivatives, there are surely more of them and not all may have been built. The first number is the first number in the basic model number. The following two numbers describes the derivative.
All Purpose is the "Standard model", so if you say 4000 you probably mean 4100...
Same goes for the other models in the 1000-series.
All this concerns 6X- and 6Y-models (1965-1975). In the 7A 600-series (1976-1981) they made a basic model 4100 with only one derivative, 420 Industrial.:confused2:
The excellent Oaktree page use "Chassis type" instead of derivative which is more descripting, all derivatives of the same basic model use the same engine.
4100 Agricultural All Purpose
4110 LCG (Low Center Gravity, i.e. Low ground clearance)
4120 Highway
4130 Rice
4140 SU (Special Utility)
4190 Skidded (Not fully equipped tractor units, were sold to manufacturers of loaders, diggers, crawlers etc.)
4200 Rowcrop
4300 Vineyard
4310 Narrow
4410 Woods Special (Logging machine, only North America)
4400 Utility
4500/4550 Industrial
Normally 4000 was on the the tractor's decal, no matter what derivative it was. 4140 had an "SU" as well on the tractor.
You can read all about your tractor's model in the tractor model number:
MODEL: D1424C
D = Model 4000 (basic model)
14 = SU (derivative)
2 = Gas (petrol) engine
4 = Independent PTO, 540 rpm (1800 engine rpm)
C = 8 speed transmission