Due to a failed rear differential pump motor (I believe that is the proper name) my car has been driving approx 6,000 miles stuck in 4WD. Long story how that was discovered, but that was verified by the Honda dealers repair shop. My feeling is that may have caused major issues that will creep up down the road. Short term my gas mileage suffered, and likely the tires are not wearing properly. Would love feedback on how this has possibly effected my car.
There are a lot of unique aspects to AWD and 4WD systems. I’m not studied in all the technical pieces and parts of your 4WD system.
Most modern 4WD systems can tolerate this sort of thing for the kind of miles you drove it. However, I’d advise getting all the fluids in the drive train drained and refilled; transmission, transfer case, and both differentials. This will assure you have new fluids that weren’t stressed by the extra work of driving in 4WD on dry pavement.
Make sure all these fluids are Honda brand fluids. Honda transmissions and differentials in particular are very sensitive to the fluids used in them.
Thanks Uncle Turbo. What about the wear on the tires? I am guessing they would have been worn improperly…yes?
Oh…one more thing to add. I noticed an instant drop in gas mileage once they replaced the rear differential pump motor…about 2-3 mpg. Again, this was after they replaced the bad motor.
So the gas mileage dropped about 3-4 mgp while stuck in 4WD, and then another 2-3 when fixed…which of course is the opposite of what I expected. Any thoughts on what could cause that to occur?
I doubt if the tires were adversely affected.
If this was a 4wd vehicle, then the answer would probably be, “yes”.
However, an AWD vehicle has a center differential to take into account the differing amounts of wheel rotation when turning.
Unless the OP heard the tires “scrubbing” when making turns, then the tires are probably fine.
Yout CRV has AWD not 4WD. This means it has a center differential which allows all four wheels to rotate at different rates when cornering.
A 4WD system doesn’t have a center differential but instead a transfer case. And on some vehicles while in 4WD damage to the tranfer case can occur.
So you did no damage by driving the vehicle in AWD.
Tester
Tester…understand they told me since the motor failed, that whatever engages when the car uses the AWD is what I was “stuck” in. They used the words “estentially you were driving in 4WD”. So are you suggesting this could have caused damage to the transfer case?
Unless you have a separate button or stick that selects 4wd, then you are always in 4wd. Most AWD are always in 4wd.
Your vehicle doesn’t have a transfer case but instead a center differential.
Here’s how this system works. When you take off from a stop, all four wheels are provided with power so it’s in AWD. Once you reach cruising speed the system reverts to 2WD in order to save fuel. So until you reach cruising speed the vehicle is always in AWD. So nothing was damaged.
Tester
Tester…thanks for the explanation. So the only “damage” was lower fuel consumption due to the fact that for 6,000 miles (approx) my vehicle wasn’t reverting to 2WD when reaching cruising speed…yes? And therefore at highway speeds in AWD - rather than 2WD - nothing could have potentially been damaged?
Exactly!
Tester