Delly, I didn't make it clear that when you take the side cover off you will then see the gear reduction case cover inside the chain case. The bolt you replace is the lower front bolt in that cover. If you go to the ls160 on messicks .com you will see that bolt sold separately because it has a hole through it. I am in the process of trying to find out what height my new hole should have been so hold off on your mod for a day or so.To answer for Jerry. The "center" of the new hole will be 2 1/2" above the bottom edge of the removable plate, not 2 1/2" above the original plug. The reason for the drilled bolt is to allow oil to enter the gearbox. Without the drilled bolt there is no way for oil to enter. The reason for raising the check plug is to allow more oil to enter the gearbox. ------------------------------------------------------ Once you try and check or add oil to the gearboxes, you will see this is a better way. The last LS machines came with this update. --------------------------------------------------------------------------------- Even if you had a drain plug on the reservoir, you would only get about 1/2 of the oil out because of the oil trapped in the hydro system, hydraulic lines and cylinder, cooler, ect. What I do is attach a hose to the bottom of one of the lift cylinders. If you look at the lift cylinder you will see a plug sticking out to the side of the cylinder. Start the engine an use your foot pedal to pump the oil out. Stop as soon as you see and hear coming out with the oil or the alarm sounds. You do not want to run the hydro pumps any longer than necessary. Before removing the plug make sure the boom is all the way down so there is no hyd pressure in the boom circuit. I usually raise the boom all the way up, shut the engine off, turn the key back on, do NOT start, and use the foot pedal to lower the boom all the way down to the ground. This will help remove some of the trapped oil.
By the way if you have doubts about doing it check the oil in yours and try to add 75-90 gear oil till it is full. It will lead possibly to language little kids should not hear.
If anyone reading this has a 160 could you measure from bottom of the chain case to the fill plug and post that measurement here?