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
  • overdrive75's avatar
    overdrive75
    Explorer
    May 19, 2020
    ^^ No drain plug, I gave up on that. All the ones that had drain plugs where those squared off ones, and after watching some of the Banks videos on diff covers squared off ones seems like a bad idea. Plus there may have been a clearance issue with the heat shield on the front of the gas tank. The nodular iron seems like a bad idea for heat dissipation. This is a Dana Spicer part fit on perfect, I used a gasket too instead of the RTV. The link is above in a post from where I purchased from.
  • pauldub's avatar
    pauldub
    Explorer
    May 18, 2020
    That’s the Spicer D80 cover? Does it have a drain plug too?
  • overdrive75's avatar
    overdrive75
    Explorer
    May 18, 2020
    Project done. 8 oz of Motorcraft friction modifier in there and 80W90 synthetic like manual called for. Old fluid wasn't as bad after I opened the cover up. New cover installed so should run cooler.

  • Grit_dog's avatar
    Grit_dog
    Navigator
    May 14, 2020
    I'd put the 140wt in the moho and the lightweight stuff in the Exploder.
  • overdrive75's avatar
    overdrive75
    Explorer
    May 14, 2020
    pauldub wrote:
    Make sure it's the right cover. The '03 E-450 has a D70-HD diff and I think the cover is different than a D70 cover.


    I have done lots of homework on this. A Dana 70-HD is the same axle housing and tubes as a Dana 80. The difference is the size of the Ring gear. The Ring gear is slightly smaller on the 70-HD.
  • pauldub's avatar
    pauldub
    Explorer
    May 13, 2020
    Make sure it's the right cover. The '03 E-450 has a D70-HD diff and I think the cover is different than a D70 cover.
  • overdrive75's avatar
    overdrive75
    Explorer
    May 13, 2020
    Case of oil is 12 quarts. So a bit over kill, but the Exploder seems to burn it easily so I will keep it on the shelf. The Motorhome the oil is roasted no doubt about it. I am going to put the cover that the F-350 had on it, to help get some heat out. I ordered this one up.

    Diff Cover
  • memtb's avatar
    memtb
    Explorer
    May 13, 2020
    pauldub wrote:
    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.


    Yep! memtb

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