Was noticing a slow to moderate leak from the transfer case. It wasn't either the input/out shaft seals as they were dry. Also, the case was wet from top to bottom so it must have been coming from up top. There is a plate/gasket that goes between the shift lever and t-case housing and upon inspection it was wet and pretty dirty.
Parts needed:
Toyota part# 36108-35060 (gasket). I read somewhere on here that 2 of these were needed. When I took mine apart there was definitely only 1 gasket, but the gasket was slightly different. Ill get into that below. I ordered 2 at ~$10 a piece but only used one.
FIPG or similar
Step 1: Remove center console trim to reveal this cover held on by 4 screws
Step 2: Remove said cover via the 4 screws
Step 3: Remove the shift lever from the T-case. There will be a breather hose attached. Slide that off so you can remove the whole part. Peel/scrape the old gasket off. I needed to use a razor blade.
Here is my old gasket. You can see it has the paper element on both sides.
Compare that to the new which has it only on one
Step 4: Clean it!! Take note of the spring location. Also make sure you reseat the boot if it comes off. It has a groove on both ends that it seats into.
Step 5: Install the gasket. I used the FIPG fully around the T-case housing gasket surface, as well as the areas show in the photo. From what I could tell this is how it was set up
originally.
Step 6: Reassemble. You will likely have to shimmy the lever around until it sits properly. Check that it's operating correctly before you button everything back up.