I am not sure 4wd on a tractor works the same, as 4wd on a pickup truck. Unless the tires are the same size, the rear tire of the tractor is much larger than the front. The tractor usually is designed with most of the weight on the rear, a pickup truck is almost the opposite, with tires of equal size. The tractor is designed to pull with the large rear tires, and basically only steer with the front. I have never noticed in any where 4wd ever helped a tractor stuck in the mud, or pull a plow. I am not saying it doesn't, but there is no obvious difference, like with a pickup truck. The mechanics, just aren't the same. A tractor just isn't designed like a 4x4 truck. There is a video on Youtube, that takes two Zeto tractors one is 2wd, and the other is 4wd, they are basically the same tractor. The 2wd tractor goes wherever the 4wd tractor does. They do a fairly good comparison in the woods on log roads, the 4wd doesn't show any advantages. The video is in like bulgarian, or something, but you can clearly see the comparison on the video on youtube. Just type in "2wd tractor vs 4wd tractor, they should be Zeto tractors. I read another article that stated that 4wd on tractors is only profitable on the larger tractors, with the front tires being the same equal size as the rear. A smaller front tire, apparantly won't really help. In other words, wherever a 2wd tractor will get stuck up, the 4wd tractor will too, only instead of 2 wheels spinning there will be 4. I have watched a lot of video's to see if I could noticed any difference, and I wasn't able to find any video's that show any difference in traction improvement with a 4wd over a 2wd. If anyone has the same tractor with one being 2wd, and the other 4wd. Same engine size, everything, and has compareded them in the same enviroment, under the same conditions, doing the same work, and knows if there is any noticable difference, your imput is appreciated. Loader work, maybe an exception, because of the weight, and load, the bucket may have on it, forcing the weight to be placed over the front tires, to create traction. A none loader 4wd tractor, I am not so sure 4wd makes a difference. Some tractors are lighter in portion to the rest of the tractors in their fronts, than other makes, or models. R1 tires get better traction than R4, or turf. Tractor is translated as traction. Tractors are designed, or originally rather, to pull. To obtain traction, and pull is the tractors original design purpose. Two massive large ag tires, are all they need really. Just two to steer is all the front was intended for. When more weight is placed on the front of some tractors, the weight balance design, is shifted taking weight off the tractors main two wheels of traction. Depending on location, and soil conditions, the weight of the tractor plays a vital part in the tractor obtaining traction. Heavier tractors can pull heavier loads generally, if the soil for example isn't to moist, wet, or damp. Heavier tractors will get stuck in wet soil, quicker than lighter tractors, but a lighter tractor generally won't pull as heavy as load, as the heavier tractor if the soil is hard enough for the tractor to get traction. Compact tractors are usually about a 1000lbs lighter than the 4,000 lb, and up small farm tractors, like the little grey fergie, ford 8n, etc.. they only have about 20-30hp, while some compacts push 60hp, but their weights aren't as heavy, so they spin. Heavier tractors can get the weight moving, because of the counter balance of the tractor itself. Tractors have place for weights to be added on the rear, and front. The Front usually is to help counter balance the the tractor, while when a tractor is pulling a heavy load, it's weight is being used as a counter balance to pull the weight of whatever it is trying to pull. The weights on the tractor are used to keep the tractor itself balanced, to direct the force of the torque, back towards the ground, on the rear tires, to again obtain traction. Notice tractors will raise up in the front, if there isn't a counter balance. like with weights. If tractors have too much weight on the front of the tractor in wet soil conditions, the tractor can create ruts for itself, and get stuck easier. I believe 4wd on tractors, may actually cause them to do the same,and to get stuck in wet soil conditions, than help them out,because of the weight of the front axle housing, and tires. Anyone who disagree's, their experience, and insight is appreciated.thanks hope this helps