Lo viscosity hydraulic oil for my John Deere?

[morninghill]

Have a John Deere 870 from 1998 with 700 hours. The owners manual says use JD Lo Viscosity hydraulic fluid, the dip stick is even stamped lo viscosity. Thats what I've been using but Ive noticed that after a few hours running, its difficult to shift, particularly in and out of reverse, and worse in hot weather.

Recently got a July 1994 John Deere technical service manual for the 670, 770, 870, 970, 1070 tractors. This manual says use regular JD Hygard or Quatrol fluid for temperatures from -25F to +122F and use the lo viscosity for -40F to +68F. I've never had to use the tractor in below zero temps, but often use it in 80's and 90's.

Any idea why the conflict between the owner manual and the service manual? Maybe a different transmission after the 1994 service manual? I'd like to switch but hate the thought of messing up the transmission.

 

[mjncad]

My 2001 JD 4200 has a similar conflict in the manual. Since most of my work is done in moderate to hot temperatures, I use the regular viscosity hydraulic oil without problems.

 

[DieselPower]

You would probably get better performance out of the higher viscosity oil. It sounds like you are having some problems with hot operation using the low viscosity oil so the higher viscosity will most likely work better for you.

 

[morninghill]

Thanks to all for the feedback. I'm going to switch to regular viscosity.