Hey Guys im just wondering when drivng in normal 2h on freeways etc does the ring an pinion turn fast like the rear ? just thinking of changinf diff oil in rear and for a second i though the front didnt turn? so i take it oils should be changed in both front and rear at same time?? also does anyone make a front diff cover ? i just ordered a PPE cover and a lubelocker rear diff gasket.. also does any one use that blow by oil canister set up for the 3.5 ltr

 

Iirc the front does not spin given the front "hubs" are vacuum actuated and the tcase is not engaged until you kick it in 4wd.

 

Normally, the front diff is NOT turning during 2WD operation. However, in at least the last 2 generations of F150 4x4 there is a program that keeps your IWE solenoid deactivated on start-up so that the hubs are locked for the first 1/4 - 1/2 mile of travel (not 'zackly sure how far) in order to "stir" the front diff lube. It's also possible that in cool/cold weather, your front driveshaft could turn for a short time--simply from fluid friction--until the lube in the transfer case warms up. Note that in neither case am I saying that your transfer case is engaged and your truck is operating in 4WD mode.

 

Even though it is used much less than the rear differential it is still subject to condensation and possibly contamination.

The rear axle heats up with normal use which helps dry up condensation.


If it was mine I would change the oil in both at the same time. Even just drawing the used oil out of the fill plug is better than nothing but not as good pulling the cover.