John Deere LX279 Drive Train problem

[Lumpulus]

I have a John Deere LX279(17HP Kawasaki Liquid Cooled V-Twin, 48 Inch deck, and Power-Flow rear bagger) that has had a drive train issue, and was wondering if anyone can shed some light...

Everything works absolutely perfect for the first 45 minutes to an hour of mowing, then as if I flipped a switch, the drive train will start shuddering\juddering, making a chattering noise, and start driving much slower. The problem occurs with PTO on or off, no difference. It is far worse in reverse than going forward.

For those of you who will say, "Take it to the dealer". I have...to 3 different dealers in my area...they all say the same thing, "we tried it for over an hour and it was fine." I just tried calling John Deere customer service, and they said "try a dealer".

Other than the mentioned problem, I LOVE this mower, it makes my lawn look like a Gold Green every time I mow, but it sure would be nice to know if there's anything I can do about it.

Any help would be greatly appreciated.

 

[rayikeo2]

When this happens have you just been mowing and collecting the grass in the rear bagger? Some times the grass will clog the drive belt when rear bagging. If it gets packed in the transmission area, shutting down the mower will not clear out or stop the problem until the grass is manually removed. Check for clogs or take the rear bagger off and run the tractor without mowing to see if the problem re-accurs. Are you using a rear trunk attachment when not mowing?

 

[Lumpulus]

I am very fastidious about keeping the mower clean, and completely vacuum it after every use..and yes, I forgot to mention I've tried it with the Powerflow and bagger assembly removed completely(side discharge) with no change at all.

I've always leaned towards this being transmission\thermal related, and am pretty frustrated that all dealers want me to do is buy a new one.... the thing is I'm perfectly happy with the Tractor other than the mentioned problem....it mows like a dream, runs forever on a tank of gas, and makes me the envy of my neighbors.

Thank you for the suggestion!

 

[rayikeo2]

I have a LX279 with a 44" mulcher mower which I have owned for 10 years and am very happy with mine as well. They are fine machines. I am assuming that at least 1 of the three dealers has checked the oil level in the transmission. At this time I can't think off anything else to check unless one of your belts, pulleys or idle pulleys gets hot and seases up after 45 minutes. Do you hear any screeching sounds? Some times belts get frayed and make a lot of viabrations for a while before they finally break. If you mow over branches some could be sticking inder the deck and rubbing the blade. I did have some problems when mowing wet grass it would build up under the deck and then start falling off in chunks that would get caught by the blades and make viabrations/shuddering noises.

 

[Lumpulus]

AFAIK, all dealers checked the tranny oil level, and I check all fluid levels before every mowing session, as well as belt tension\wear.(Yes I'm very ****)

I avoid mowing after rain or if the grass is wet, but if I have to I have no issues..the power flow attachment really does a great job shooting the grass up the tube into the bags. I never wait for the tube airflow indicator to activate when emptying the grass bags, relying instead on a quick feel of the right bag to see how full it is.

I really don't think this has to do with the mower parts, but again, thank you for the replies and suggestions!

 

[rayikeo2]

One more thing I thought of is the gas tank cap. The next time this problem happens stop the mower blade leave the tractor running and try to unscrew the gas cap. If it is extra hard to unscrew and you hear a pressure/vacuum hissing sound when it comes loose you have a bad cap vent hole. That problem can cause the mower to slow down and eventually die because the fuel pump can not overcome the vacuum and you get fuel starvation. If you find this is the cause it needs a immediate fix as it will ruin the fuel pump and the pump will need to be replaced @ $130 + labor. Gas caps are about $12. Leave the cap loose until you can get a new one. This may not be your problem but it's a problem I learned by experiance, the hard way. My mower would run 30 to 40 min then die as if hot. I let it set for 1/2 hour to cool down and it would restart and run for another 30 to 40 min. Instead of needing to cool down all it needed was for the tank to lose the vacuum working against the fuel pump, it wasn't hot at all. Then the fuel pump started leaking onto the muffler shield. I was lucky it didn't catch on fire.

 

[Lumpulus]

Nope...the engine does not stumble or lose power in any way, it runs like the day I bought it.

 

[Deadman]

Does it possibly have the wrong weight fluid in the tranny?

 

[Lumpulus]

Does it possibly have the wrong weight fluid in the tranny?

The manual says 5w30...that's what's in it.

 

[Engine_Tech]

Sounds like once the trans oil gets hot you start losing drive. The hotter the oil, the thinner it gets, and the more can get by worn pumping parts.

Changing the existing oil and replacing it with regular JD Hy-Gard hydraulic fluid (not the low-viscosity version) may get it back in the game.

Dealer probably can't reproduce it as they are not actually driving the machine, they are probably just letting it run for an hour which won't build any heat in the trans.

Go for the oil change.