The John Deere 2040S from the 40 series gets its own overview here, with more than 350 parts such as lighting, electrics and engine components.
Keeping a John Deere 2040S at work means dealing with the jobs an older tractor brings: a clutch, an alternator, a weeping gasket. For this member of the John Deere 40 series, this page lists more than 350 parts from GRANIT, HELLA, LUK, MAHLE and VICTOR REINZ.
There are clutch plates, single clutch assemblies and internal plates, partly from LUK. Once the tractor is split, replace the clutch plate and pressure plate together. Splitting engine from gearbox is the costly part of the job, not the parts. Check the flywheel for heat spots and scoring and have it skimmed if needed, then use an alignment tool so the input shaft slides through the new plate without forcing.
For the engine there are gaskets, seals, O-rings and sealing rings, such as a seal for the feed pump, an O-ring for the oil pump and sealing rings for the injection nozzles. There is also a gasket for the lift housing. Always use new nozzle sealing rings, because a used one is already crushed and will not seal reliably a second time.
Alternators and starter motors come in several versions, so compare flange and pinion with the unit you removed. Relays and radiator hoses are available too.
Track rods cover the steering and universal joints the driveshafts. A universal joint that feels notchy in one position needs replacing, even if it does not rattle yet. Bushes for the lower link struts and tubes complete the picture.
After replacing a track rod, the toe-in will not be right on its own. Count the turns as you unscrew the old rod, screw the new one in the same amount, and have the toe-in checked afterwards. A radiator hose that feels soft or cracked with the engine cold should go, together with its clamps.
Bushes for the lower link struts wear oval over time. If the linkage knocks when you lift an implement, check the bushes before looking at anything more expensive.
The serial number is on the type plate. Many parts on this page also carry a John Deere reference number, which you will often find on the old part as well.
Other tractors from the 40 series with their own page are the John Deere 1640, John Deere 3640, John Deere 4040, John Deere 4240 and John Deere 4440. For the brand as a whole, see John Deere parts.