If you have a John Deere D125 lawn tractor (aka ride-on mower), or pretty much any of the D-series, and have ever replaced the oil filter, then you’ll know how annoying it can be.  The crux of the problem is that:

• the ‘proper’ oil filter (the AM125424 for a D125) is a very short filter
• the oil filter is positioned so that there is very little clearance between the filter and the frame

This causes a couple of issues:

• there is not enough clearance to use many oil filter removal tools
• there is insufficient room to hand-tighten the new oil filter

The solution is rather simple:  Install a longer oil filter!

Providing that a longer oil filter will not come into contact with the closed hood, or any other moving part, you can simply buy a (slightly) longer one and install that instead.  The fluted end of the oil filter will then project beyond the frame which will make (un-)installing it a whole lot easier.  The larger filters sometimes even cost less, because they are used on more machines and produced/stocked in larger quantities.

(Of course this design issue/fault affects many other lawn tractors, not just the JD D-series.)

The ‘slightly longer’ oil filter that I have been using on the D125 is the AM101207.

The second tip is pretty common knowledge, but worth repeating anyway:  After you’ve smeared a small amount of fresh oil over the rubber gasket on the new filter, and wiped clean the part of the engine block that the gasket will mate with, screw on the new oil filter and then hand-tighten it firmly in place.

There is absolutely no need whatsoever to use a tool to install an oil filter, and risk damaging it.  Even the tiniest hole or crack will ultimately lead to oil loss and very bad things happening to the engine.  If the new filter is clean and your hands are relatively oil free, you should be able to get a good grip with both hands and torque the filter enough to ensure a solid seal.  You don’t need to go ape on the thing.

Finally, with your new filter installed you’ll fill up with fresh oil.  Once you’ve got the oil level between the two notches on the dip-stick, run the engine for about thirty seconds.  Any trapped air should get purged from the system.  Check the oil level again and you’ll see it has dropped a little.  Top up (if required) to bring it back up to the desired level.

If you don’t take the time to perform this extra step, you may end up running the engine with inadequate oil which will result in increased engine wear and premature failure of certain components.

Oil filters may not be sexy, but they are very important and filter changes are worth taking the time to do right.