Front differential gear lube foaming up, should I be concerned?

[Alan Peters]

Guys, I have a issue with the the fluid on the front differential. I drove about 400 miles this weekend and throught I would check the fluid level. As soon as I removed the plug, foam came out. I used valvoline 75w-90 synpower. I don't hear any noises or issues, but this is concerning me since the gears may not be getting proper lubercation with air trapping between the gears. Should I remove the oil and replace it with something else or is foaming normal? I removed the plug about 5 minutes after driving.

 

[Bill Barber]

Remove the gear Lube, you got water in the diff.

 

[Alan Peters]

Just removed the old fluid. Should I replace it with Mobil 1? Or put standard dino back in?

 

[Mike Caldwell]

I think all gear lube comes synthetic, atleast the 75w 145 stuff does. So it comes down to brand prefrence.

 

[Kevin Palmer]

I agree, I think you have water in there as well.



Should be just a matter of changing it.

 

[Bill Barber]

Than ck the vent tube if you have one, not sure

 

[Alan Peters]

Ok just changed it. Funny thing is the clean fluid was on top and the dirty was clearly on the bottom. No evidence of water that came out. 1.6 quarts came out. Took it for a 10 min drive and removed the plug and all it good so far. The dude at the auto parts store did recommend on putting dino 80w90 in and testing it out. I'll drive it for the next couple of days then see if its still foaming. The auto parts dude did say the friction modifier that comes with some synthetics does play are part in front diffs some times. We will see.....