Just did mine today, had tried a few of these bulbs from Amazon and they worked fairly good so I got more 194 168 T10 Wedege SMD High Power LED HYPER WHITE BULBS Dome Lights 12V (1 pair) : Amazon.com : Automotive (had previously ordered another type of bulb and they were garbage)
The clear part just slides down, they have about 3/4 inch sides that extend straight up into the tailgate housing and it seems to be just a friction fit because they didn't seem to snap in or anything. I just used a dental probe type thing, a little on each side slide it down. You'll end up with a clear rectangular little cup. The bulb then just pulls out like the others. Replace bulbs and slide the clear "cup" back up into the housing.
