[8D] Hello mate, I have also heard that mineral grease with time can cause some types of plastic to become brittle, I haven't heard anything about the gearboxes on Tanks myself. I think I read somewhere that Tamiya Tankers avoid it, any advice on this Guys?[sm=50_50.gif] I also have read threads on what grease to use in tamiya car gearboxes. Mineral grease or grafite grease will attack certain types of plastic but thankfully Tamiya car gearboxes and gears seem to be unaffected. I remember reports on tamiyaclub.com of 20+ year use on mineral grease so no problem with the nylon type plastic but other kids of plastic may be affected. A possible alternative would be silicon grease. This can include teflon for low drag. I use this on my air weapons because I know mineral grease will eat my seals over time.