DIFFERENTIAL & HUB OIL

[John Sinnar]

I have a 2006 Patriot Thunder 525.  A few months ago I had the differential and oil bath hubs oil replaced with 80/140 synthetic oil.  Monaco specifies 80/90 conventional oil in differential and hubs.  Was this a wrong decision..............?

thanks

[Karl Welhart]

John,

Ok, you are going to get many different opinions on this issue.  Here is mine...  I would have used 75/90 Synthetic gear lube for both applications.  Your diff may have already had synthetic gear oil, If so, you would be good for a lot of miles.  The hubs will be good with synthetic, by just checking the level.

So, the answer to your question is NO, you did not do anything wrong.  What you did is better than conventional oil in both the diff and hubs,  However, in our MH applications, lighter weight synthetic oil is much better than conventional oil.

[Edward Buker]

John,

This is an example from a Dana Spicer truck differential service manual which your motorhome may have. On page 28 you can see the graphs. The 80w 140 is one of the better choices as Karl mentioned giving you a useful temperature range of -10F to well over 100F. The 80/w90 does not go over 100F which we have certainly exceeded on the road before. Synthetic 80W140 is probably one of the best oils on the market for your application given the very wide use temperature range and excellent lubricating qualities.

http://www2.dana.com/pdf/AXSM-0866.pdf

Later Ed

[Gerald Farris]

John,
I agree with your choice in hub oil. I run 75W140 synthetic oil in my coach, because it gives a much better high temperature range than the 80W90 oil that Monaco recommends. With the oil that you are running, you get the same low temperature performance as the oil Monaco recommends, but much better high temperature performance.

Gerald