Not all diesels are the same. The air cleaner for my Monaco Diplomat was about $50.00. The canister type for my for Dutch Star is about $150.00. You also need to factor in the air dryer dessicant filter about every three years and the hydraulic fluid filters, both not used on gassers.
The extra oil is expensive too. Mine takes 27 quarts. Pretty much, I think most people do an oil change once a year, both on gassers and diesels. Lastly, if you factor tires into the mix, the DP tires are generally more expensive and a tag axle adds two more.
