How often do you guys change your diff oil? Maintenance schedules aside, I'm thinking every 30,000 mi. or so. Too often? I'd like to go for some Royal Purple in there. Also, when changing without taking off the cover, how do you guys drain?

 

Just changed it for the first time at 97,000 although I'm going with 50,000 mile intevals from now on. Pulling the cover is the easiest way, but you can use a suction gun. It takes longer and is less complete, but no mess.

 

I end up going through deep water before any significant amount of milage so I end up changing more often than others.

I pull the cover to make sure any metal shavings come out with a good cleaning. Reseal with RTV and your good. Don't forget if you are limited slip to add Ford's bottle of friction modifier.

Adrianspeeder

 

I'm on my original fluid (190,250 miles) Hydraulic oil doesn't wear out unless it gets really hot. I've never read the owner's manual in regards to this, so I don't know what it says about it.

 

While it is true that hydraulic oil lasts a long time... that's not what is in your diff. 75w140 synthetic (rear) I would change it at about 100K or so, unless you tow alot, or go in the water.

 

Ford-design axles are lubricated for life. These lubricants are not to be checked or changed unless a leak is suspected, service is required or the axle assembly has been submerged in water.

 

Yeah. The manual says it's lubed for life unless you go into the water or, I believe, tow a good deal. My Haynes manual, however, mentions something about checking it at 30,000 mile intervals, and changing it at 60,000 mi. if necessary. I supposed I need to just drop this concern, huh?

I can be guilty of overkill on preventive maintenance.

 

do whatever helps ya sleep better at night.

i hate to make it sound like that manuals the holy bible for your truck. its a guide and if you feel better having your diff. oil replaced then do it.

heck if you take it to your dealership, and the mechanics honest and knows what he's doing, he'd probably ask you why you want it changed if it hasn't seen any hard service or been submerged.

but most likely he'd smile and say, " yup, you got 'er in here just in time, she was about to explode".

BUT like i said. do what make YOU feel better. i've come here with the same questions and gotten all kinds of answers but in the end i did what i thought was right. and if what i thought was right turns out to be what these wonderful people told me then cool.