RT4WD, Did I Ruin my rear Diff? RT4WD knowledge needed!

I have been getting really crap gas mileage lately (20MPG) and I couldn’t figure out why. Today, I discovered that my rear drum break was having some real issues, and on the passenger side had been dragging. This is at least part of where the problem has been coming from.

However, once I discovered this, I assume it means the vehicle has also been running in “4wd” as the front and rear wheels would not have been turning at the same rate.

My concern is that I have done damage to the rear diff, but its hard for me to tell. Im not sure how to test it.

With the car on the list, if I spin the driver side front, the rear follows. However if I do the same to the passenger side front, the rear passenger side (where the break was dragging) does not turn as well. I realize that the RT4WD system is not symmetrical, but is this normal?

Is it somehow possible to “burn out” one side of the rear diff, and not the other? I would have expected to get “burnt” fluid small, much like a failing transmission or clutch, but I haven’t noticed anything other than the described above. Spinning just the rear axles, both sides feel the same.

Someone with knowledge on how the RT4WD system works, please chime in!

Comments

  • realtimefunrealtimefun Senior Wagonist
    ciz the wheel is draging it will no sping as free the car has open diffs so it wont spin every wheel
  • 91civicZC91civicZC Wagonist
    Im not sure I totally understand what you mean.....
  • 91civicZC91civicZC Wagonist
    Anyone?
  • ragenasianragenasian Moderator
    Honda's Real-Time four wheel drive system is designed to provide the benefit of all wheel drive in slippery conditions, without the penalties of extra drag, higher fuel consumption, greater tyre wear and increased noise which accompany conventional four wheel drive systems in conditions when the extra traction is not needed.

    The other benefit of Real Time 4WD is that its engagement is completely automatic - there are no extra levers or buttons, the system automatically engages drive to the rear wheels when it senses that the front tyres have started to slip.

    The Real-Time 4WD system incorporates a compact transfer case which distributes drive to a propeller shaft which runs to the rear differential. There are also two hydraulic pumps, one driven by the front wheels, the other by the rear wheels. When the CR-V is operating on dry pavement, the front and rear wheels are turning at the same speed, and so are the two pumps. If the front wheels start to turn faster than the rear wheels (due to loss of traction), the pumps turn at different speeds. The resultant differential hydraulic pressure activates a valve body and feeds pressure to a multi-plate clutch, which engages the propeller shaft to the rear differential, thus feeding drive torque to the rear wheels. The amount of drive going to the rear wheels is proportional to the amount of front wheel slippage.

    The system automatically disengages under braking, thereby allowing the ABS system to operate.

    4wd only kicks in when the front wheels starts to slip. I dont' think you have any problems, just change the brakes and hope for the best. Be prepared to change out a lot of old parts though. I changed out everything when my brake was sticking. This also caused my fronts to wear unevenly too so I had to change out pads, rotors, brake lines, springs, drums, shoes, brake cylinders, and the master. It was a freaking mess.

    Good luck.

    Oh and while you are at it lube up the front caliper slides to make sure those also aren't sticking a little. A lot of people neglect those.
  • pfff. alot of questions al at once ... and complex things too ...
    and i dont know a thing : )

    if one wheel, circumstances whatever, 'drags' you initially should have noticed
    a steering problem, as in when breaking or steering, car pulls to one side...

    that 4wd is based on a fluid, that engages when turningspeeds of rear and front
    axels differ at a certain point, hence the differential ...

    so whatever your driving speed is (theory) all the wheels spin at a close to same rev ...
    drum issues or not ... driving not as in slipping

    Crappy mileage could start with something that simple as your airfilter,
    maintenance is the keyword, for all of us ...

    Anything is possible, you finding some answers in my reply and/or THE
    answer from somewhere/one else

    : )ps. dont ask me why, coz i dont know
  • 91civicZC91civicZC Wagonist
    Crappy mileage is due to breaks, almost guaranteed. The point of Hondas "RT4WD" was always to maintain gas mileage while offer a 4WD system "when needed".

    Sticking brakes usually wont do that much to your steering, at least nothing that I have ever noticed. If they are sticking enough that your steering is affected, you would usually have some kind of smoke show happening out back, this was not the case at all here. This was basically just a light rubbing, but enough that I would bet the car has been in "4wd" for at least a few weeks.

    I’m pretty good with my maintenance, cant imagine anything else is the culprit (other than a head gasket, but dont think that’s the case).

    What really concerns me is just that the When the car is off, and out of gear, when I turn the front wheels the rear turns on the drivers side, the rear follows. But when I do the same on the passenger side (where the rear drum failed) the front turns, the rear does not.

    Keep in mind this is with the car "OFF" and not in gear, so I guess this isn’t the best comparison. Ill wait till I have it back in the air and have it in gear to see if everything is still turning.

    What I was hoping to hear was from someone who understood Hondas system better than me, to tell me if a failure on one side without the other failing was even possible (rear diff), as I dont see how it is, but I could be wrong?
  • 91civicZC91civicZC Wagonist
    ragenasian wrote:
    Honda's Real-Time four wheel drive system is designed to provide the benefit of all wheel drive in slippery conditions, without the penalties of extra drag, higher fuel consumption, greater tyre wear and increased noise which accompany conventional four wheel drive systems in conditions when the extra traction is not needed.

    The other benefit of Real Time 4WD is that its engagement is completely automatic - there are no extra levers or buttons, the system automatically engages drive to the rear wheels when it senses that the front tyres have started to slip.

    The Real-Time 4WD system incorporates a compact transfer case which distributes drive to a propeller shaft which runs to the rear differential. There are also two hydraulic pumps, one driven by the front wheels, the other by the rear wheels. When the CR-V is operating on dry pavement, the front and rear wheels are turning at the same speed, and so are the two pumps. If the front wheels start to turn faster than the rear wheels (due to loss of traction), the pumps turn at different speeds. The resultant differential hydraulic pressure activates a valve body and feeds pressure to a multi-plate clutch, which engages the propeller shaft to the rear differential, thus feeding drive torque to the rear wheels. The amount of drive going to the rear wheels is proportional to the amount of front wheel slippage.

    The system automatically disengages under braking, thereby allowing the ABS system to operate.

    4wd only kicks in when the front wheels starts to slip. I dont' think you have any problems, just change the brakes and hope for the best. Be prepared to change out a lot of old parts though. I changed out everything when my brake was sticking. This also caused my fronts to wear unevenly too so I had to change out pads, rotors, brake lines, springs, drums, shoes, brake cylinders, and the master. It was a freaking mess.

    Good luck.

    Oh and while you are at it lube up the front caliper slides to make sure those also aren't sticking a little. A lot of people neglect those.

    Hmm, interesting, this may mean that the rear wheel brake being on wouldnt put in into 4wd mode then? Is it reliant completley on the Front wheels?

    THis is coming up during probally the worst time it could too. I'm driving the car about 1400 Miles on saturday, so this is a rush rush fix problem. That means I dont get to do the work, my friends shop does. Hes pretty good to me, but still bucks down the drain. But while trying to move a whole house to another country, I just dont have the time do deal with it.

    Also in the middle of fixing my AC, my wheel studs, and some other small parts. Arrrggggggg!
  • bam-bambam-bam Council Member
    Sounds like you're ok, just fix the brake. What you're describing is the way any differential functions, the side with least resistance will turn, and it's designed so that the wheels can travel at different speeds (as in cornering.)
    The brake dragging shouldn't have affected the 4wd atall, unless it locked up and the front wheels spun trying to drag the rears!
    Just check your car over like you normally would, and have a safe trip!
  • Bam he is the man ...

    who couldnt love having him around ...

    sigh...

    : )
  • 91civicZC91civicZC Wagonist
    Bam, it sounds like you may need a restraining order for Eagle.
    :D

    Thanks for the Tip, thats what I wanted to hear!

    Moving the Wagon out of california, and hopefully into some snow in the winter, it should like that!
  • 91civicZC91civicZC Wagonist
    bam-bam wrote:
    Sounds like you're ok, just fix the brake. What you're describing is the way any differential functions, the side with least resistance will turn, and it's designed so that the wheels can travel at different speeds (as in cornering.)
    The brake dragging shouldn't have affected the 4wd atall, unless it locked up and the front wheels spun trying to drag the rears!
    Just check your car over like you normally would, and have a safe trip!

    Thanks, I was pretty worried I broke my favorit toy, without ever having really gotten to beat it up!
  • restraining order
    Whaaa LOL ... F* man, you got me ... u got me ...

    i had to read it twice before it hit me ...
    dam U

    :lol:
  • 91civicZC wrote:
    Bam, it sounds like you may need a restraining order for Eagle.
    :D

    Good thing he's accross the ocean. LOL
  • he's accross the ocean
    I'll take that as a challenge...

    I can fly :wink:
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