I have a 1988 toyota pickup 4x4 5 speed. I took it hunting and went throught a lot of mud then the next day I was driving down the road and it started making a roaring noise for the front right. It's not wheel bearings cause I already checked em. I'm thinking it's the axle but idk if an axle does that.

Indeed ... Good answers BOTH,..

Nature sides with the hidden flaw..
If those CV or U-joints have any play (worn)
the lack of balance will make itself known

Vibrations & noise...
So I will only add (because 1988 was a good year)

Once cleaned & lubed.. (as suggested)
Have a helper go around and turn the wheels
(one-by-one) while you watch and feel the
DRIVELINE for any looseness...

I see some new PARTS in your FUTURE...
(better to check out PRICES when you don't
need them).

Parts are AVAILABLE...
http://www.rockauto.com/en/catalog/toyota,1988,pickup,3.0l+v6,1277614,drivetrain

Hope this helps

Carnac the Magnificent

Could be a few things but as vibrations from the drive train can travel....First grease all the u joints to eliminate that.
could be the cv joint.
had one case where it turned out to be the rear diff. weird!
getting it up on a lift will definitely give you a resolution.

Needs a good washing under the axle area. Sounds like the mud dried and causing friction