Here's another:
"As I mentioned in my last e-mail the K58, although it is in a small package, similar to the K46/K57 case size, is indeed as strong and durable as the K62 that it replaces. With the introduction of new technologies and materials we, here in the transmission industry, are finding new ways to accomplish the same functions in a smaller package than we were able to 8 years ago when the K62 was developed. This is similar developmental progressions as is experienced in most products; whether it's engines,
computers & other electronic equipment.
The biggest detriment to life of a transmission is excessive oil temperatures (>90°) resulting in reduced lubricating (cushioning between components) characteristic of the oil. Thus, scouring of mating parts'surfaces will occur, increasing internal leakage and in turn lowering
efficiency of the transaxle. Your first inclination that less oil in the K58, due to physical size, will affect its durability. But, In fact, the K58 has nearly same internal reservoir capacity as the K62. (2.4 vs 2.5
liters).
There are other area of the K58 that contribute to controlling oil temperature other than internal oil capacity.
1. Fan size (dia.) of K58 is larger than what has been recommended on K62 contributing to increased air flow (cfm) over the external surfaces of transmission case.
2. The charge pump of the K58 contributes to a more efficient, cooler operating transmission. K62 is not equipped with charge pump. Tuff Torq's similar model K66 does feature a charge pump.
So, once again the K58 has same rated torque and durability specifications as the K62. Our durability bench tests prove this out. On the other hand,
our OEM customers (such as JD) must determine, through extensive testing, if the transmission they incorporate, satisfy their project needs in life & performance.
Rated and continuous torque are the same.
Hope this helps you better understand the workings of Integrated Hydrostatic Transmissions (IHT).