Krawlin- " just putting some think shock oil in their tranny? "
That would actually be ok, unless it's silicone. Silicone is good for lubricating plastic on plastic and not used as a high load lubricant.
Petroleum is good for plastic/plastic, plastic/metal and metal/metal.
I have fill/drain holes in both my diff housings and the top of my trans, which allows me to assemble all of the above dry. I use a small syringe to fill, no better way to avoid the mess like paralyzed seems to not like