How do I tell if my 4wd is working?

[jparsons]

I tackled some trails today that were a lot of fun - the toughest spots were about 70% of what the crv could probably handle. At one point I was going up a gravelly hill, and the front tires started spinning but the rear wheels didn't spin at all. I thought maybe, since the weight was sitting on the back wheels that's why they didn't spin but I don't know...

How can I tell if power is going to the rear wheels? Snow will be coming soon and I want to make sure 4wd is there when I need it.

[twl845]

I tackled some trails today that were a lot of fun - the toughest spots were about 70% of what the crv could probably handle. At one point I was going up a gravelly hill, and the front tires started spinning but the rear wheels didn't spin at all. I thought maybe, since the weight was sitting on the back wheels that's why they didn't spin but I don't know...

How can I tell if power is going to the rear wheels? Snow will be coming soon and I want to make sure 4wd is there when I need it.

As a new 4wd 2010 crv owner, I'd like to know that also.

[tsmithvt]

I tackled some trails today that were a lot of fun - the toughest spots were about 70% of what the crv could probably handle. At one point I was going up a gravelly hill, and the front tires started spinning but the rear wheels didn't spin at all. I thought maybe, since the weight was sitting on the back wheels that's why they didn't spin but I don't know...

How can I tell if power is going to the rear wheels? Snow will be coming soon and I want to make sure 4wd is there when I need it.

The official method is to put the vehicle on a lift (all four wheels off the ground) or securely jack all four wheels free of the ground. For Vs equipped with a MT, place the transmission in 5th gear with the engine warmed up and idling and engage the clutch. At least one wheel on each axle should rotate. Slowly engage the e/p-brake and when the rear wheel(s) stop turning the engine should stall.

For Vs equipped with an AT, place the transmission in "Drive" with the engine warmed up and idling. At least one wheel on each axle should rotate. Slowly engage the e/p-brake. The rear wheel(s) should stop rotating and the front wheels should (ideally) slowly come to a stop as well.

There is another test method for ATs that involves jacking only one front wheel free of the ground also, but it requires a good working e/p-brake and well chocked wheels to prevent the vehicle from coming off the jack (which it will try to do if the RT4WD System is working). With the engine warmed up and idling, place the transmission in "Drive". The one free front wheel should rotate slowly and then (ideally) stop after approximately three to five revolutions. This method is frequently used but is also very risky because of the tendency of the vehicle to drive itself off the jack. I read one account of testing using this second method that ended with a hole in the passenger compartment floor from running over the jack.

Don't be too alarmed if the front wheel or wheels don't come to a complete stop or the engine doesn't actually stall. There are a host of reasons why you might not get a perfect test result. As long as you get an obvious response from the system, it's probably OK.

[twl845]

The official method is to put the vehicle on a lift (all four wheels off the ground) or securely jack all four wheels free of the ground. For Vs equipped with a MT, place the transmission in 5th gear with the engine warmed up and idling and engage the clutch. At least one wheel on each axle should rotate. Slowly engage the e/p-brake and when the rear wheel(s) stop turning the engine should stall.

For Vs equipped with an AT, place the transmission in "Drive" with the engine warmed up and idling. At least one wheel on each axle should rotate. Slowly engage the e/p-brake. The rear wheel(s) should stop rotating and the front wheels should (ideally) slowly come to a stop as well.

There is another test method for ATs that involves jacking only one front wheel free of the ground also, but it requires a good working e/p-brake and well chocked wheels to prevent the vehicle from coming off the jack (which it will try to do if the RT4WD System is working). With the engine warmed up and idling, place the transmission in "Drive". The one free front wheel should rotate slowly and then (ideally) stop after approximately three to five revolutions. This method is frequently used but is also very risky because of the tendency of the vehicle to drive itself off the jack. I read one account of testing using this second method that ended with a hole in the passenger compartment floor from running over the jack.

Don't be too alarmed if the front wheel or wheels don't come to a complete stop or the engine doesn't actually stall. There are a host of reasons why you might not get a perfect test result. As long as you get an obvious response from the system, it's probably OK.

I can't speak for JParsons, but I think we're talking about realizing the 4WD kicked in or not on actual road conditions. Other than the fact that the car moved off successfully in snow, will you feel the 4WD as it activates, or is there a sudden lurch forward when it kicks in? In other words how do you know your in 4WD as opposed to the normal front wheel drive. I don't want to be tooling along thinking I'm in 4WD when I'm not. I've had 4WD on all my cars, and I would put them in 4WD and know I am driving in 4WD. This real time 4WD is new to me and if I can't tell if it's engaged, I won't have the confidence I had in my other cars.

[aggreX]

IME in the snow the system engages seamlessly. In 05 the RT4WD system was improved "cam-driven AWD mechanism replacing the pump system improving acceleration and hill climbing performance". To "challenge" the system in the snow I accelerated aggressively over ice or snow from a stop and got confident forward motion with just a bit of front wheel spin with the VSA kicking in. The V was stuck momentarily in very deep snow drifts last winter that would challenge many AWD vehicles but some gentle forward and reverse maneuvers got the V out without assistance. The V has Michelin X tires which are 80k rated A/S street tires

[twl845]

IME in the snow the system engages seamlessly. In 05 the RT4WD system was improved "cam-driven AWD mechanism replacing the pump system improving acceleration and hill climbing performance". To "challenge" the system in the snow I accelerated aggressively over ice or snow from a stop and got confident forward motion with just a bit of front wheel spin with the VSA kicking in. The V was stuck momentarily in very deep snow drifts last winter that would challenge many AWD vehicles but some gentle forward and reverse maneuvers got the V out without assistance. The V has Michelin X tires which are 80k rated A/S street tires

aggrex- Thanks for the explanation.

[tsmithvt]

IME in the snow the system engages seamlessly. In 05 the RT4WD system was improved "cam-driven AWD mechanism replacing the pump system improving acceleration and hill climbing performance". To "challenge" the system in the snow I accelerated aggressively over ice or snow from a stop and got confident forward motion with just a bit of front wheel spin with the VSA kicking in. The V was stuck momentarily in very deep snow drifts last winter that would challenge many AWD vehicles but some gentle forward and reverse maneuvers got the V out without assistance. The V has Michelin X tires which are 80k rated A/S street tires

The "Ball Cams" were added to cut down the reaction time required by the dual pump system alone. It was a refinement of the dual pump system not a replacement for it.

http://www.hondanews.com/channels/20...c-35004c34bfa1

The last section ("Real Time 4WD") deals with this improvement which, as you said, was added in 2005 (Gen 2.5) CR-Vs. It's very difficult to see in the illustration but the Ball Cam Assembly was added just ahead of the clutch pack. The assembly is right at the very front end of the differential assembly. It's operation is pretty well explained in the News Release but boils down to two plates with cam channels cut into their mating faces. These paths are angled in the longitudinal (with respect to the companion flange/shaft center line) direction. Balls are housed in the cam paths so that the plates try to separate from each other when the plates are rotated in opposite directions (the balls roll up the cam ramps). The plates collapse back together when they are rotated in the same direction. Like the two pumps, the two cam plates are driven, one by the propeller shaft and the other by the differential pinion shaft.

The ball cam change/addition can, perhaps, be envisioned better by comparing the illustration in the above reference with the illustration on page #4 of the following reference.

http://www.skidmore.edu/~pdwyer/e/files/rtawd.pdf

It's actually a very elegant system (RT4WD). It's light, simple, fully automatic and all without the use of electronic control systems. It also operates seamlessly, which can be a problem. Confidence just comes with use.

[annekat]

JParsons has a 97 and I have a 99, not the newer improved versions mentioned above. My mechanic did one of the tests described above and apparently it works. I'm hoping for a little snowstorm here in NW Washington so I can get out there and see how it feels, and whether I can "tell". A friend who has a 2005 says she can't "tell" but her husband can, or so he says. Around here, FWD will get you through most stuff, but I'd hate to be in Michigan or somewhere and wonder if for sure the 4WD was working.

[twl845]

JParsons has a 97 and I have a 99, not the newer improved versions mentioned above. My mechanic did one of the tests described above and apparently it works. I'm hoping for a little snowstorm here in NW Washington so I can get out there and see how it feels, and whether I can "tell". A friend who has a 2005 says she can't "tell" but her husband can, or so he says. Around here, FWD will get you through most stuff, but I'd hate to be in Michigan or somewhere and wonder if for sure the 4WD was working.

I know guys about two hundred miles north west of me near Buffalo, who use GPS in their cars in the winter because some times they can't tell where the road is. They don't drive CRV's.

[aggreX]

The "Ball Cams" were added to cut down the reaction time required by the dual pump system alone. It was a refinement of the dual pump system not a replacement for it.

It's actually a very elegant system (RT4WD). It's light, simple, fully automatic and all without the use of electronic control systems. It also operates seamlessly, which can be a problem. Confidence just comes with use.

Thanks for the updated information on the ball cams. My sources were from two respectable magazines that were a bit mistaken about the RT4WD improvements for 05. Regardless it has provided me great snow/ice traction for the past 5 winters. The power to the rear wheels feels more linear and somewhat more confident than my 04 Pilot. The Pilot has a more sophisticated system but under some icey conditions it has fishtailed a bit ....something I never felt when the RT4WD system engaged.