I have an L5740 and it has been 100% trouble free for now 18 years. Great tractor. I agree that ballasting is important. Loaded tires is essential, and I also added steel wheel weights which made a big incremental improvement. Knock on wood, I haven't had any HST leaks, or any leaks for that matter.
If you are running ag tires and going to replace them, BKT makes a front tire that is 8 ply vs the standard 6 ply. They have a significantly higher weight rating and work MUCH better with heavy loader loads. The stock tires smoosh nearly flat when the loader is full.
For comparison I went from an L4630 w/glideshift trans to an M6040 geared.
Totally different machines from frame and wheel size to lifting And moving ability. I mostly use it for snow removal and logging which is the main reason I upgraded to be able to handle large timber. The L was fine when used within its capabilities but no match for M
I had a L5740 from 2010 to 2015 trading it for a L6060 when the FWD seal on the shaft out of the transmission failed and was leaking so bad from the weep jiggle pin under the center housing I couldn't use it. The dealer had 2 other Grand L's in front of me for the same repair. I needed the tractor so bad I made the swap. Only other problem was losing front wheel bearings on each side but that is an easy repair. Reason for failures was too much load and carry but if you watch for oil leaking on the insides of the front wheels, you'll catch it before it becomes a major repair.
My GL5740HSTC went in the shop yesterday and won't move, this is mentioned on several forums, but so far no one has replied what happened. Mine had the split ring repaired under warranty and the cab stayed on. If you've been around shops, you know all about "flat-rate" and the WSM is not the gospel. As to L-GL-MX-M. I ALWAYS drive before I buy. If I didn't have bigger and smaller than my GL5740HSTC, I would prefer the MX, but would jump on either that came up first. I use wide stance, fluid filled rears with weights and minimum of 2000 pounds of rear ballast and replace tires with 8-10 ply. Always keep in mind that the voices of experience can really be helpful, but only go so far. ADDENDUM: I've broken red, green, orange etc. tractors.
