790 50 hr

[ipwanab]

Just performed new tractor's 50 hour maintenence. 74 dollars worth of filters and oils. Engine oil was easy. Trans oil drain point did not match the manual. I had to drive a screwdriver through the trans filter to get it loose, then pulled mesh screen from trans (no filings or dirt in screen). The fluid looked as new but I changed it anyway. I read varying opinions on trans fluid replacement at 50 or 500 hr. Mine did not look as though it needed to be changed. Had to remove one rear brake linkage to remove trans screen. Also reversed front wheels recently. The tractor now feels much more solid than the small offset would indicate-placebo?, anyway I can now cut on a slope that I was afraid of previously. I am now down to 12 lbs air in front and 11 in rear (R4'S), and think front could use even less but I am afraid of lower pressure.Tractor is performing very well to anyone interested in 790. I have been cutting foot deep wet grass for about 5 or 6 hours every weekend with no problems.

 

[neilw]

The older 790 handbooks calls for first engine at 50 hrs and transmission at 200 hrs and differential at 400 hrs. The electronic version on the JD site now calls for engine and transmission at 50 hrs.

I changed all lubricating fluids last year at about 50 hours. Found a few small metal slivers in the strainer and cutting open the hydro filter revealed a few more metal slivers. Analysis of the OEM fluid did not show any unusual microscopic wear metals.

Listed below in PPMs:

Iron 11
copper 2
lead 5
moly 12
phos 324
zinc 1409
mag 305
cal 369
silicon 14 (probably anti-foam agent rather than dirt)