Moderator: volvite
If you are in AUTO mode on pavement at high speed, you are essentially in 2WD unless a slip occurs. The transfer case uses a wet clutch and can apply power at varying levels and as needed to obtain proper traction. It can also anticipate a slip based on speed and throttle position. If you are doing normal driving on dry pavement, you shouldn't feel any difference between 2WD or AWD. I don't in my 06 LE and I use AUTO all the time.Clay350 wrote:Auto mode is nice but it doesnt seem like a good idea to have it on if you were on pavement moving at speed. That kind of defeats the purpose for me being able to have more traction on roads that are snowy and icy part of the time. Am I wrong on this? I can feel the difference at 50mph on normal roads?
See I thought the same thing but thats not the case. If im in auto on dry road I feel the front engaged. Many people have said the same. Granted at a lower coupling rate. 4wd just isnt meant for pavement at high speeds regardless of the coupling. Am I wrong here? This is not a true AWD setup just a fancy 4wd configuration.smj999smj wrote:If you are in AUTO mode on pavement at high speed, you are essentially in 2WD unless a slip occurs. The transfer case uses a wet clutch and can apply power at varying levels and as needed to obtain proper traction. It can also anticipate a slip based on speed and throttle position. If you are doing normal driving on dry pavement, you shouldn't feel any difference between 2WD or AWD. I don't in my 06 LE and I use AUTO all the time.Clay350 wrote:Auto mode is nice but it doesnt seem like a good idea to have it on if you were on pavement moving at speed. That kind of defeats the purpose for me being able to have more traction on roads that are snowy and icy part of the time. Am I wrong on this? I can feel the difference at 50mph on normal roads?
So, for those of us slumming it without the auto feature, what is the difference there? When 4wd is engaged I was figuring the center diff was locked with a 50/50 split (hence the speed limits) so I never engage unless I'm on something slippery and disengage if, for example, the road is only partially snow covered. Am I wrong? If so how should I deal with mixed surfaces?smj999smj wrote:R51's use open diffs front and rear with electronic limited slip that uses the ABS system to brake a free-spinning wheel to allow power to go to the wheel with the traction, so, there is never a time when all four wheels are working equally as drive wheels at the same time, even in regular four wheel drive mode.
I'm not sure how they are in the UK, but the North American models have open differentials front and rear. They have "electronic limited slip," where the vehicle used the ABS system to apply brakes on the slipping wheel so the traction wheel gets more power. It works okay...and I noticed a number of other manufacturers, including Mercedes Benz, use the system in some of their vehicles.DavidUk11 wrote:As I understand it from this thread, the front and rear differentials don't "Lock" is that correct only the centre diff I us that correct?
I want to create an override so that I can use Lo ratio at low speed without any diffs locked. Possible or not do people think?
I will have a look at the workshop manual.