Have tried all the mentioned solutions to the transmission problem for my JDL120 and just had it in recently to the dealer-they say if it continues(which it has- works well for about 45 minutes on flat lawn- then as I do the slopes- it hardly moves-they say transmission fluid is topped up) has over 380 hours on it. Should I be looking at a conversion kit for the John Deere and would that help?

Hi,
I hate to be the bearer of bad news, but the first versions of the transaxle used in the L120 had problems. Some developed them in warranty which was fine for the owners. Others went a bit longer.
Try finding the number for the Deere HelpLine and calling it. Have your date of purchase, or if it is registered, just the serial number which can be found above the left rear tire under the fender on the frame and should start with"GXL10...." for 13 alphanumeric characters. They may be able to help.
I know how to check the fluid levels and did it for the factory on a few occasions on failing and failed transaxles. A new transaxle is generally the cure; the new ones are definitely better.
Peace,
Clarke