Synthetic or Petroleum gear oil for DC-380 planer?

[Michael Heffernan]

Just picked up a Delta DC-380 (22-680 single phase) planer. It's in great shape, but I want to replace the gear oil. I got a quart of petroleum based 85w-140w extreme pressure gear oil, but I've read in a couple of places to use synthetic EP oil. Does it make any difference?
Not buying from Delta; it's like $15 bucks for a pint and you need 20 oz for the gear box.

[Robert Maloney]

I used synthetic in mine. Just preference.

[Mark Bolton]

With the load/wear these planers see on a hobby level or even a small shop level about anything is overthinking it. The fact that you are even changing it is impressive. I know what the manuals say but the real world is the real world.

In that planer Synthetic vs petro is just a matter of are you willing to spend the slight extra. It just comes down to.. Get something in there and use the thing.

Just my 0.03

[Mike Seals]

As some one who has spent a great deal of time in the machine lubrication world, and a very avid fan of synthetics, I would say that in your case, no, I wouldn't waste the extra money. The temperatures and pressures you are dealing with are not going to matter, you just need the EP.

And with out going into an elaborate post. In the US, oil companies can sell an oil (Group III) that is cracked in a process that yeilds high viscosities (V.I. >120) and is not a true synthetic, but can be sold here labeled as such. But not in many other countries. Only Group IV polyalphaolefins oils are labeled synthetics in most other countries. So unless you know the base stock for the oil, what you are getting here in the US maynot be what you think it is.

Use what ya got and be happy.

[Michael Heffernan]

Thanks, I'll stick with what I already bought.

[Peter Quinn]

I use hypoid gear oil, 85W IIR, pretty sure its synthetic.....pretty sure a quart was around $3.85. The delta oil is a total scam. Not sure synthetic is strictly speaking necessary, I hadn't bought anything yet so it made sense to me.


Uh....quick price check, no way my gear oil was synthetic. Was $3.85, hasn't failed in 5 years, I have no idea how old that brown sludge I drained out of it was. Bought it used, sat for a long time, decided it was a good idea to start fresh, but not so good I wanted to do it every six months.

[Loren Woirhaye]

I acquired a similar planer recently and lacking a manual I pulled out the filler plug which is also the screw that holds the cover on the ouside of the gearbox, covering the sprockets and chain. I wanted to lube the chains so I ran the thing and oiled them. Some oil came out the gearbox hole so I was wondering: should I top it off while the planer is off?

[Michael Heffernan]

Loren, from what I've read, if you don't know what type of gear oil is in the planer, it's best to drain the gear box completely and refill with EP 85w-140w gear oil, petroleum or synthetic. Not good to mix oils.

[glenn bradley]

I agree that since (if) the oil is changed as recommended and the planer is not in a production house, it probably doesn't matter. Just don't mix your oil types; drain and re-fill if changing types, yes?

[Loren Woirhaye]

Thanks for the insight.