You have to crawl under the front, I assume yours is a desiel, and there are two canisters with manual drain valves, you have to turn them manually to open them. Here is a link to a member of this group, he really has some good ideas on safety and getting under these units.
I am not sure how else to do a link, I am sure there is a better way. His user name is quikduk (Ken)
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