Forum Discussion

overdrive75's avatar
overdrive75
Explorer
May 10, 2020

Rear Axle Fluid Change Differential Cover with drain plug.

So here is the scoop, our 2003 Winnebago 29B is built on a 2003 Ford E-450 chassis. I am doing my annual maintaince, and decided this year is the year to fix my rear end seepage from between the diff cover and the diff. Chassis has 44,000 miles on it, so not a ton. Fluid is pretty stinky and black in there as well. So owners manual says 80W90 oil for the axle. I have a case of 80W90 synthetic on the way. Also have a case of 75W140 Motorcraft on the way as that is what goes in the diff on the towed car (2003 Explorer). So question what fluid is everyone running in there. Owners manual says 80W90, best I can find is 50k mile change interval, so I am almost at that. All this said being a 4.56 I bet this axle runs hot, so was looking to swap covers out for one with a drain plug. Has anyone done this? Which cover are you using? Also what oil is everyone using in there? Thanks
Class C
  • pauldub's avatar
    pauldub
    Explorer
    May 13, 2020
    Ford specifies the Motorcraft 75W-140 for the '03 E-450 for hot and hilly trailer towing. Hauling a house seems pretty close to trailer towing.
  • Grit_dog's avatar
    Grit_dog
    Navigator
    May 12, 2020
    And if you’re wanting more severe duty oil, bump to 75-110 or 75-140.
    Oh and all gear lube stinks. If it’s been burned or heated excessively. You’ll know it. The level of stink goes up immensely!
  • Grit_dog's avatar
    Grit_dog
    Navigator
    May 12, 2020
    Buying a new diff cover is a waste of $imo.
    How many more times do you plan on changing the oil? It’s good to take the cover off anyways.
    By cases of oil , you’re ordering 24qts of oil to do 2 vehicles that take a total of 7-8 qts?
    Plan on stocking up for the next 3 oil changes?
    Seriously, remove cover, dump fluid. Replace fluid with whatever you bought at Autozone earlier in the day and move on. Not a project worth overthinking.
  • memtb's avatar
    memtb
    Explorer
    May 11, 2020
    I went to a Mag-Hytec on our Ram 3500. An aluminum cover with additional fluid capacity, having raised ribs on he case outside for greater surface area for additional cooling. It has a magnetic drain plug, a sight glass for easy level observation, and is drilled/tapped for a temperature probe (should you desire one)! They’ve been around many years! I’m not sure what fluids Ford used in ‘03, but with my Ram, I went to a higher weight rating ( I tow quite heavy loads) full synthetic oil...... Mobile 1 differential lube! Any good differential oil should be fine......nothing wrong with using the oil that Ford spec’d the vehicle with! memtb
  • overdrive75's avatar
    overdrive75
    Explorer
    May 11, 2020
    ^^ Thanks for the tip on the looking at the banks website. I really like there covers and would love to get one of them, however it looks like in 2007 ford went to a different axle on the E-450's as the ones they have on the banks website are 12 bolt covers. Mine is a 10 bolt cover.
  • noteven's avatar
    noteven
    Explorer III
    May 11, 2020
    Before you swap out the cover take a look at Banks website for a video of how diff cover design affects lubrication of the axle gears.
  • DownTheAvenue's avatar
    DownTheAvenue
    Explorer
    May 10, 2020
    If it were me, I would follow the manufacturer's recommendation for the weight and type of oil to put in my vehicles.

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