I was about to do this mod as i have to reverse my boat up the driveway after every fishing outing, and the idea of having 2L in a manual sr5 sounded awesome, but before i did it i started to think about why we don't see 4wds standard with 2L and what could go wrong mechanically with this mod.
I'm not a mechanical engineer ( but i was forced to do some mechanics in my electrical engineering degree
) and from my basic understanding, shifting to 4L increases the torque to all four wheels by 2.566 (Transfer gear ratio 1.000/2.566). In 4L the power would be split 50/50 front
to rear meaning that the torque should also split 50/50 front
to rear, and the front
and rear driveline hardware both see a maximum torque 2.566x higher than in 4H. But preventing the ADD from engaging, wouldn't that send 2.566x more torque than in 2H to the rear driveline, possibly causing damage if the hardware isn't designed for that kind of torque?
I'm not entirely sure about power and torque distribution when the front
and/or rear wheels are slipping, but what i do know is with an electric motor under no load, it is only developing enough torque to overcome friction to keep it spinning. If a similar analogy can be applied here, under normal operating conditions in 4L, when the front
wheels have no traction (no load) causing the wheels to slip and spin, does only enough torque to overcome friction get send to the front
and all the remaining torque generated get transferred to the rear wheels? If so, then i'm laughing because then i'll be sure the rear driveline hardware has been designed to cope with the extra torque. If however my logic here doesn't apply, and only 50% of the torque is sent to the rear wheels even when the fronts have no traction and are spinning, then i'm a little hesitant to do this mod for fear of busting the rear differential or the like.
Some thoughts, comments and explanations would be appreciated.