I have my moments!I learned something new today. Yeah, olds!!!
The 985MG has an o-ring built in around the output shaft and the case parts. I'm not sure, but I want to say it also has o-rings on the case screws.
The only place I recall putting RTV on my two were around the power lead grommet and I tried to work some into the wire leading into the grommet.
The primary reason I buy the 985's and promote them so much is due to the o-ring on the output shaft. There aren't a lot of $70 servos that do that... well, that and have 172oz/.13 sec @ 6V ratings.
Mine have been practically submerged in water. I ran my aftershock last year in the snow/slush/rain/wet grass and I hit it with a garden hose in the summer. I just make sure to at least blow the standing water off of the servos when I park it. No point in tempting fate completely!
I use the 985MG primarily as a t/b servo due to them almost always standing up, so water rests on them and gets into them more frequently than steering servos. I've only had one or two steering servos go bad with general RTV on the case halves/screws/lead and an o-ring under the horn. Been bashing for 8+ years in all conditions. I've gone through 14-15 throttle servos though with the same treatment. That stopped when I bought my first 985MG before running my aftershock last winter. Didn't even have so much as a glitch then or now.