Diff oil change

[CatMan-do]

Changed my diff oil today, F/R,the rear oil came out dark green.. the front came out light green and had a little foam in it , must have got some water in it from the deep water ride at Snirt. I'll put 10-15 miles on and change it to see what comes out. I used Valoline 80-90w full syn...hope i didn't hurt anything.. this is the first time i changed diff oil 950 miles..

[GreatWhiteHunter]

I change my diff oil at the beginning and end of the season and at least once during and it's always "foamy". I asked about this on ArcticChat and at my dealer (Wheel-A-Way) and so far, from everyone I've talked to, this is normal. The oil in there gets quite hot and when combined with the moisture that develops inside the pumpkin when the machine sits, creates an oily froth.

[JoeR]

Don't worry about the foam.  It's normal.  Oil companies add an anti-foam agent to diff lube (probably a surfactant) to reduce foaming.  It doesn't eliminate it, and it doesn't have to.  It just needs to keep the foam down enough to prevent it from escaping out the vent, which it does just fine. 
What you don't want to see is white diff lube.  That would show water intrusion.  Diff lube with suspended water makes for a crappy lube.  THAT would hurt the diff.  Not foam.

Joe

[GreatWhiteHunter]

Don't worry about the foam.  It's normal.  Oil companies add an anti-foam agent to diff lube (probably a surfactant) to reduce foaming.  It doesn't eliminate it, and it doesn't have to.  It just needs to keep the foam down enough to prevent it from escaping out the vent, which it does just fine. 
What you don't want to see is white diff lube.  That would show water intrusion.  Diff lube with suspended water makes for a crappy lube.  THAT would hurt the diff.  Not foam.

Joe

That's a MUCH better description than mine.

So - 

[JoeR]

That's a MUCH better description than mine.

So - 

Not really....like usual, I said the same thing, just with a lot more words.   

One day I'll learn to just Get To The Point!

[CatsJ35]

If you do find that it is foaming out of the vent try running Lucas 80-90 holds up great  for me. I change it once a year right after the SNIRT every year, and most on here can attest to the abuse I put my machine through. Can also try running a PCV valve and then small filter on the end of your vent lines to keep mud out if you like to get in the deep nasty stuff.

[GreatWhiteHunter]

If you do find that it is foaming out of the vent try running Lucas 80-90 holds up great  for me. I change it once a year right after the SNIRT every year, and most on here can attest to the abuse I put my machine through. Can also try running a PCV valve and then small filter on the end of your vent lines to keep mud out if you like to get in the deep nasty stuff.

That's a good idea, I might switch to something like that.

Cat puts an expanding bulb type device on the end of the diff vent hose to keep the entire thing "sealed". I'm not 100% sure that it does that, hence the reason I change mine so often. It's such a small amount of oil and it's so easy to do that I just can't see not doing it.

I'll look into that Lucas stuff for sure. I've been using their extra thick power steering fluid in my truck and it has worked quite well. Had a small leak and the pump was making some noise. So it's stretched the life of the equipment considerably (well past its time).

[CatMan-do]

Well, glad the foam was no big deal, but why the too different greens? different oils F/R? I have enough oil left over to change it again , will do that sun and see , Thanks,