What year did the D8T first get the new lockup torque converter?
Can't give you exact information but the only D8T model equipped with a lockup converter is the AW4-prefix machine. First production of the AW4 was some time around the middle of 2018.
Not 100% but I believe it was 2018
I must ask what good would a lock up converter be in a dozer? Dragging a ripper fuel economy perhaps
I recall that the Dark Side tried it a number of years ago and it didn't end well.
My thought would be long pushes. The old agg tractors were standard transmissions because torque would overheat pulling plows and other implements
The lock up uses several conditions to allow power loss through converter. The Tcu takes in consideration T/C input and output speed engine speed,selected gear and slope. When conditions allow the converter is bypassed for less power loss through the converter redirection. Fuel efficiency is improved. Similar to one way over run stator but easier controlled by Tcu. Still even used in conjunction with the freewheel stator.
I've never seen one myself but according to the SysOp it's a lot more complex than that. It has a freewheel stator like all the other Cat lockup clutch converters I've ever seen.
I have scene a few and did not explain it as complex as system operations just an overview. Rebuild and calibrate on a regular basis
What's the most common failure mode.? Sprag clutch letting go.?
For the lock up failure it was a plug in the end of the input shaft T model dozers.The freewheel one way clutch had issues but has been updated. Cam and rollers improved increased rollers