I have foamy gear oil leaking from the front axle on the passenger's side. I think it might be the seals but don't know. If it is, how much of a pain are axle seals to change!?

 

I have to assume four wheel drive , something is wrong , the gear lube should not foam , have you checked the level ? Had it checked ? Added any ?
Any front end work done recently ?
I should be 3/4 inch below fill hole .
Depending on how hard it comes apart , in shop conditions , it could take most of a day at best , remove front wheels , hub/bearing assembly's , all axial's , differential .

 

Does it say this in the Manual, or is this just what everyone does?

I Myself always fill trannies, diffs, transfer cases, etc level with the fill plug.

 

it was just my guess, it's not exactly foamy but grey like water got into it.

 

If its grey its got water in it. Me and a buddy of mine changed the driver side seal out on my 03 in a couple hours in his shop with air tools and a couple of jacks. The aam axles are probably easier to do because they have adjuster rings like a ford 9in not shims. I would fill to about 3/4 of an inch under the fill hole or it will work its way out again.

 

I use the 3/4 " , because others have said it was in the manual , mine started to leak after doing axial u-joints & ***** , because of talking the axial out , so then I filled to the hole , would leak more and quit when it got to 3/4 below [ cold weather ] then when it warmed up , it started leaking again , I think that the gear lube expanded to above the 3/4 level and leaked , so now I want to do the seals before I put synthetic in .

 

I don't recall if the manual has that tip, but it's common knowledge among techs that leaving the gear oil level at least a half-inch under the fill hole will avoid a lot of the leaks. Don't forget to make sure the axle vent is clear, or the internal pressure can build and force oil past the seals.

If you do need seals, I recommend the CR brand over the NOK; even though they interchange in the housings, they are different designs - CRs cost slightly more and are definitely a superior design. Don't rely on Dodge for the correct parts, since they have a glitch in their parts system that's been sending the wrong seals from India in bags with the right part number.

I use Quad4x4 for power transmission bits & pieces - Dan is very knowledgable and helpful, and his prices are reasonable with fast service.

 

pita to do but the passenger side can be done without pulling the diff out, u just have to take the cad system out. the drivers side u need to pull the diff.

 

As a additional seal, MADD 4 WHEEL DRIVE makes a outer seal that in installed right at the end of the axle tube, sort of a pre seal. This helps to keep crud from getting in there in the first place.
Some have a easy time getting the inner passenger seal installed using sockets and other items, I spent way too much time fighting it. A real PITA for me. A friend made me a really cool set of aluminum jigs that make the job of installation take but a few minutes. If you decide to install them and you want to borrow the jigs, PM me.