So here's the deal. I opened up the front axle to do the axle seals. Cleaned it all out and everything looks good. Put it all back together and filled her up with 75/90 valvoline gear oil. Take it for a spin and when I get back home I hear a bubbling sound as if water was boiling. I could hear it clear as day coming from my axle. So what's with this? Is it normal or maybe the wrong gear oil? Should I worry?

 

No one has any input? I take it this is not something anyone has run into?

 

Are you sure it's coming from the axle?

 

100% sure it coming from the axle. The housing also feels a bit warm to the touch

 

Got me baffled. If it were hot enough to boil oil you couldn't touch the housing. That leaves air bubbles, but there isn't any obvious source for that either.
75W90 valvoline should be fine, I don't think that's the issue.

 

What did you use to clean it out with? Gear lube is sensitive to cleaning solvents. For example, mineral spirits will turn gear lube to a milking looking substance. Not good.

The FSM calls for SAE 80W-90 gear lube in the front differential.

 

I pulled the gears and cleaned the housing with brake parts cleaner. I wiped it out and completely and let it sit for an hour or so before I put it back together. I checked the breather tube to make sure that was clear as well. I'm stumped

 

my guess is that it was the engine / radiator that made the bubbling, but because you just worked on the frontaksel, you wanted to hear it from there. the aksel will allways be warm to the touch when driving for a bit.

take it for another drive and see if it does it again,
remember to check the level on the coolerliquied.

good luck with it

 

Sounds good.

 

Ok so here's what I found. I opened the axle again and found a ton of sludge. I changed it all yesterday when I did the seals. So I cleaned it again and put new fluid in. The bubbling noise is gone. By the way it was not the radiator. I ran the truck for 30 mins. And no noise at all. Only happened after a ride and now its gone. Any idea how this happened? Brake cleaner some how affect the gear oil? Problems gone so I guess it don't matter but its bugging me.

 

Gear lube is very fussy about mixing with other chemicals. Perhaps you didn't wait long enough for the brake cleaner to completely evaporate before adding the gear lube. I had to use a quart of gear lube to flush my differential out completely after cleaning it before I adding the final fluid. I used an old fashion style oil squirt can to get the flush lube way up inside. No problems since.