First of all, let me say we all have questions about the r/c tractor-trailer & construction hobby from time-to-time. This is a great place to ask them to get the answers you need.
Gear Reduction Units: The unit is used to slow the speed of the truck and can also increase the power of your truck. They are best used for when trying to negotiate an steep decline with your truck, it helps to slow your truck so you have more control instead of just speeding down-hill recklessly. They are also of great benefit when you want to maneuver at slow speed for precise motion without hard-jerking or that instant jumping than can occur so often when receiver seems to glitch a little. With the increase in power you have more torque applied to the drive-line. In this manner you can increase you pulling capacity and it in turn keeps you from getting stuck in situations that the stock-transmission wouldn't be able to manage as well. Other members on the forum can better answer further questions about these type units.
AD-to-Trans. Reduction 4:1 available @
www.gardentrucking.com
Driver Figures: The action figures used most often are the Bruder construction men & women. However there are other figures that work just as well. CAT put out a line of action figures that work OK and then there's the Nylint Men-of-Steel Collection - long out of date and a bit pricey, but very much to scale. You can also get figures from
http://verkerk.modelbouw-onlineshop.nl/ or take your chances with your local toy store.
Globeliner; Peterbilt or Kenworth: They both have their appeal, and they both have their pro's & con's to replicating them. You need to decide if you really like the KW's that are seen everyday on your streets or if you want something different. Once you know what you want to build, the parts are out there for you to get. Each build will have challenges of it's own, and no two builds will ever be quite the same. As for where to get parts, there are plenty of places, here on the forum and on the world-wide-web (including Ebay).
Look to these vendors as just a starting place and be sure to check the forum (
many of our members sell items here for our own use):
http://www.gardentrucking.com
http://www.ihbcustommachining.com
http://www.truescale-rc.com
http://jtsrctruckshop.myshopify.com
http://verkerk.modelbouw-onlineshop.nl
Good luck with your project.
- RCT