SAE140 equivalent for today

[freedomlives]

Sometime ago I posted about my dillema as to which gear oils would work for my tractor and walk-behinds, as the market has changed since their manuals were written in the 1980s. I hadn't noticed the "fine print" in the Iseki manual for the TS series, and that being that the TS3510 is supposed to get SAE140 gear oil, not SAE90.

Its been running on SAE90 or 85W90 since I got it last year.

The options I see are 75w140 or 85w140. The former being full synthetic, the latter dino. Assuming that in a tractor there is nothing to be gained using a full synthetic oil, right?

 

[freedomlives]

And, of course, I wonder if the 140 weight oils are necessary with today's gearbox oils? The smaller TS series tractors all had 90 weight oil specified, just my gearbox calls for 140.

 

[RjCorazza]

I use 75w140 synthetic in all of my gear boxes, even the ones specifying 90 weight. Synthetic is certainly not necessary, but for the small quantity involved I prefer it over non-synthetic.

 

[LouNY]

A synthetic is a higher quality lubricant, is it required, most likely not, is it going to hurt, heck no.