Changing diff fluid

[Cruzomatic]

Lately when launching and retrieveing the boat due to the lakes low water levels, I have to really back my truck down in the water. I know/read/heard that submerging the trucks differential in water is bad for it as it can suck up water possibly causing problems. How frequently do you all service the diff on your tow vehicle? My '99 F150 5.4 V8 auto 3.55LS has 101,000 miles on it.

 

[Silvertip]

Re: Changing diff fluid

There is a vent at the top of the housing. If that's ever gone under water you would be well advised to change the lub. If the water level never got over the pinion (drive shaft) level you are probably ok. If it routinely gets over that level or half way up on the wheels, both rear axle seals could suck water especially if the housing is hot from an extended road trip.

 

[RubberFrog]

Re: Changing diff fluid

I think at 100k it is safe to say you should change it. I do mine at 50k.

 

[beezee28]

Re: Changing diff fluid

I think most manufacturer recommend changing diff fluid at about 60K. I changed mine at about 65K.

 

[DJ]

Re: Changing diff fluid

You have to pull the back cover, no big deal.<br /><br />Since you have a limited slip, the Ford Limited Slip modifier is a MUST, on the change. Otherwise, it will chatter.

 

[cr500r]

Re: Changing diff fluid

For my truck, the manual states that if I tow, which I do, or go offroad, which I also do, that I should change my diff and t-case fluids at 15,000 miles, so for the lousy $10-15 it costs, I do it every 15,000 miles. I have a limited slip rear end and as long as I use an oil that is good for lsd's I'm good to go, I went with Valvoline this time and had used Castrol in the past as their oil is compatible with lsd's.

 

[barazor]

Re: Changing diff fluid

an idea is to get some air hose or fuel line(a lot of guys pick up a length of retractable pigtail hose at harbor freight) and make an extended differential breather. you take the stock breather off the axle and replace it with a hose barb fitting(most are NPT pipe thread), then attach the hose to it and reroute it somewhere away from water, like just below the bed. some guys even put a filter on it.<br /><br />this is a really easy modification to do, it's very popular with people who go 4 wheeling where axles are exposed to a lot of water and mud.