Marquis differential oil change

[Jeremy Parrett]

Gerald,
  Do you have any information on doing a differential oil change?  I know mine has not been changed ever.  Should I use a synthetic?  Is this a job the average handyman can do?

[Marty and Suzie Schenck]

If it has never been changed, I would change it.  I would also put in synthetic.  I have been underneath and serviced my moho many times, and yes this is something a handyman can do.

Marty

[Gerald Farris]

Jeremy,
By the published maintenance schedules, your differential oil is past due to change. However since your differential came with synthetic oil, you would probably not benefit yourself by changing from used synthetic oil to new mineral oil since synthetic lubricates so much better.

The maintenance schedules for your differential were written with the assumption that it would be used at very high torque for at least 1,000,000 miles. So neglecting to change the differential oil will shorten the expected life of your differential, but probably not to the expected amount of miles that you will ever see on your coach. Back when trucks ran on standard mineral oil in the differential (before synthetic),
a lot of trucking companies would overhaul the differential as part of their scheduled maintenance every 250,000 to 300,000 miles to prevent problems on the road. However I do not know of anybody that is doing that now.

The bottom line is that if you change the differential oil, only use synthetic. It is something that the average shade-tree mechanic can do without a problem if he has the right tools, and a way of disposing of a lot of used oil. However it is not something that should be moved to the urgent needs list.  

Gerald

[Jeremy Parrett]

Thanks Gerald. I will get the oil replaced with synthetic at our next scheduled service.