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I was putting a boat in off the end of a boat ramp and my CRV got stuck. i have a 2000 CRV with AWD and I have made it through deep snow and started fine on icy roads on hills, so I was suprised. However, truth be told the boat was heavier than it should have been, around 1100 pounds with a fairly good tongue weight of around 150-200 pounds. The left front tire was spinning out in the sand and none of the other tires were moving (it was all sand). I had to unhitch the trailer, in the water and then i was able to drive out of the sand and my brother came in with a truck and pulled out the boat. My question is, why didn't the rear tires try to catch at all? Was it because of the 150 pound on the back making the front end lighter and fooling the AWD?
 

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It might be that the drive train is engineered to pull 1500 lbs TOTAL with 10% tongue weight on a level incline on a dead stop. How much does the trailer weigh? The incline might have been enough to make the trailer heavier, or harder to pull, not to mention it makes it harder for the CR-V to pull itself up the hill in the first place. But I am interested as to whether BOTH wheels have to be turning before it will engage the rear differential, or there has to be movement to engage it at all...

Stephanie
 

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I believe hitting the brake pedal disengages the AWD, so if you were riding the brake to keep from rolling backwards down the ramp, that would have probably kept it from kicking in.

I applaud the effort, but trying to tow a heavy weight, on an incline, in the sand with a CR-V... you're experience sounds about like what I would expect from that scenario. Did the AWD kick in when you released the weight and started moving forward out of the sand? I'm sure there was some tire spinning there, the AWD should kick in when the front tires are spinning faster than the rear.
 

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My understanding is that the rear differential kicks power back to the rear in cases where the center driveshaft is moving at a different part than the rear wheels. IE, if your front wheels are spinning, so is the center driveshaft, and your rears are stationary, then the diff locks up.

So, that said, the CRV has a standard or open front differential (like most FWD cars that lack limited-slip diffs), which means that if one wheel has no traction, it has no resistance and therefore spins freely while resistance keeps the other in place. This is a common occurance in many FWD cars during winter.

Now, when that happens on the CRV, because that one wheel remains stationary, the center driveshaft is also stationary. Because the center driveshaft and the rear wheels are both stationary, the fluid is not pumped through the reservoir, the clutch doesn't engage, and the rear wheels continue to receive no power.

That's just my understanding, and it could be incorrect. The system is actually really simple compared with most AWD systems; it's just that it takes quite a bit of knowledge to really be informed about it! Hopefully someone can confirm.

Bottom line (if I'm right), make sure both front wheels have somewhat equal traction, so that they can both either get grip (in which case you're golden), or both spin ... because if they do that, you'll get rear wheel power coming online in short order.
 

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Wow.
I hope someone who has knowledge of how and when the rear wheel drive kicks in comes forward and answers your question. I'd like to know also.
Buffalo4 :)
 

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Wow.
I hope someone who has knowledge of how and when the rear wheel drive kicks in comes forward and answers your question. I'd like to know also.
Buffalo4 :)
Here are two of many tried and true explanations of how the RT4WD System works. Both are old and a little out of date (some of the later improvements like the "Ball Cams" are not covered) but they cover the basics.

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

http://townhall-talk.edmunds.com/direct/view/.ef229e9/0

The explanation starts at paragraph #10 of the second reference.

In addition there are many explanations right here on the CRVOC site.

http://www.crvownersclub.com/forums/showthread.php?t=9124&page=2

In post #12 of the above reference I attempted to explain how transmission torque is fed through (or around) the front differential to the RT4WD System/rear differential.

Hopefully the above references help with questions you may have about the system. If you have more, ask away. The answers are here.:)
 

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I was putting a boat in off the end of a boat ramp and my CRV got stuck. i have a 2000 CRV with AWD and I have made it through deep snow and started fine on icy roads on hills, so I was suprised. However, truth be told the boat was heavier than it should have been, around 1100 pounds with a fairly good tongue weight of around 150-200 pounds. The left front tire was spinning out in the sand and none of the other tires were moving (it was all sand). I had to unhitch the trailer, in the water and then i was able to drive out of the sand and my brother came in with a truck and pulled out the boat. My question is, why didn't the rear tires try to catch at all? Was it because of the 150 pound on the back making the front end lighter and fooling the AWD?
After reading some of the info in the links provided by tsmithvt, it sounds like your rear diff clutches may be non-functioning or worn out. The link with a test to see if that might be so can be found in posts #30 and #32 by "jpirie".
http://www.crvownersclub.com/forums/showthread.php?t=9124&page=2

Buffalo4
PS: Yes, your rear wheels should have been getting power when the one front wheel broke traction.
 

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I believe hitting the brake pedal disengages the AWD, so if you were riding the brake to keep from rolling backwards down the ramp, that would have probably kept it from kicking in.
Actually I think for my initial braking theory to be correct the car would have to have forward motion. So scratch that...

The way I read the description of the AWD function from spdrcr5's link, if the front wheels (clutch guide) are rotating faster than the rear wheels (hypoid driven gear), drive force should be applied to the rear wheels in a properly functioning rear differential.
 
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