5W-40 Synthetic Oil in JD 440C?

[Downeaster]

Good morning all,

I have a JD 440C skidder that I was going to change the oil/filter in, but after reading the manual for the appropriate viscosity oil, I am not sure that I should use what I use in all of my other diesels.  I normally use Rotella T6 5W-40; however, the manual states that it should be straight 30 above 32F.  According to the manual, you can use 10W-30 -10F to 32F.  Any of you older Deere guys have any comments.  I am probably overthinking this, but want to keep the old girl healthy.  Thank you in advance for your input.  

[Kodiakmac]

I replaced the worn out 219 in my old 440 with a 239. All I ever used was 10W-30 in both engines.  But I'm sure there are synthetic oils that will do the trick.

[Brian_Rhoad]

The Owners Manual for my 440 says 10W-30 is ok from -10-90 degrees Fahrenheit.

[arojay]

I've been using Rotella T6 5w40 in my 440B since rebuild break-in, summer before last.  That is to say, I ran straight 30 for break-in then changed over.  I used 0w40 for about 15 years before rebuild.  I went to 5w40 because thats what I run in my other diesels, like you and I began working the skidder more in summer.  The book was written in the 70s, maybe early 80s for your C, before synthetics.

[teakwood]

That is what i was gone comment, oils have come a long way since that book was wrote, and i'm pretty sure your fine with the modern oils