Great info Ian. Thanks so much,
You are welcome.
It's now my understanding that the ridge is a true 4wd that cuts to 2wd at cruising and when needed VTM cuts power to wheels without traction to transfer power to wheels with contac, or the VTM can be manually engaged in 1,2 & R.
Just got this 2012 sport and love it but want to know the full mechanics so I don't do any damage and can maximize it's many features.
4WD purists probably wouldn't consider it to be a true 4WD, but rather an AWD system. Either way, it's one of the best drive systems on the market, especially in the truck market, for staying on a road. That's any road, from smooth pavement to rural fire roads. In combination with the independent rear suspension and good tires, it's the safest vehicle in its class for any weather.
Off-road, it's also pretty good, though not in the same class as conventional 4WD systems with fully mechanical drive systems. The VTM-4's rear drive is engaged with electric clutches, meant for brief usage. In normal driving, even off-road, they'll only be engaged for short bursts of a few seconds at a time. If you engage VTM-4 Lock, those clutches will be given 100% power (meaning up to 70% of the vehicle's torque) until the lock is disengaged. If you leave the lock on for more than a minute or two, they could heat up enough to do some damage, with the main concern being to cook the rear drive fluid. VTM-4 Lock is meant for brief usage in special circumstances, such as getting out of being stuck, when the computer might not leap to the right conclusion about torque distribution based on slippage (reactive mode) or pedal pressure (proactive mode).
Chances are that you could drive the vehicle on-road and in fields for years and never need to engage VTM-4 Lock. It's quite likely that you'll want to use VSA Off in fields though, since sinking in or being up against the walls of ruts might make VSA think that it needs to reduce power to avoid wheel slippage. That is an on-road programming bias, and VSA Off tells the computer to get out of the damned way for you.
There is no damage risk from VSA Off, though it might tempt you to rev up a lot to use wheel spin to get out (which is kind of the point). Excessive actions like this can damage the transmission, which is in common with other brands' automatic transmissions.
I'll look for tpms stems for winter but can I run without them if I can't get them? Just keeps a light on it something?
This time of year is perfect for looking for dealer or local tire shop special offers for winter tire/wheel/TPMS packages. Because of economies of scale, they can often match the best on-line deals. I recommend getting a real set of Honda wheels, as they will have the right strength ratings.
BTW, if you've never used a TPMS system before, some advice:
1. Make sure that you never lose a stem cap. Road grime in there will ruin the sending unit.
2. Use only plastic stem caps, not metal. They can corrode and be difficult to remove.