Interesting note on today's http://whatif.xkcd.com
Voyager actually had problems because of missing oil changes. No, really.
The imaging on Voyager was actually done by moving a single pixel sensor on a mechanical scan platform. Because of vacuum welding and other problems relating to operating metal gears in a vacuum, the gearbox for the scan platform was enclosed in a pressurized, grease-filled box.
By the middle of 1981, as Voyager 2 was passing Saturn, it was discovered that the scan platform was failing to turn itself properly. They looked at Voyager 1, and discovered that it had done the same thing back in 1979.
The problem was probably that there was some kind of crap- maybe a metal shaving- blocking the gears from meshing properly. And obviously getting out to Saturn for a quick jiffy-lube visit is going to be expensive. So what they did was to run the platform backwards and forwards until it started moving smoothly again. You know, like you might if your '77 Plymouth Voyager was sticky going into gear- you would work the shifter a bunch of times til it starts to mesh properly.
They ended up doing a software patch to stop Voyager from going into safe mode when the scan platform current got too high, so they could achieve this cycling without it taking forever.http://ntrs.nasa.gov/search.jsp?R=19830062955
tl;dr- Voyager’s had tape over the OIL CHANGE DUE light since 1981.