It’s a 2004 CRV, and at the sharpest steering angle, low speed of course, I hear a low pitch groaning, and can slightly feel the vibration too. I don’t know whether it’s coming from the rear diff or the steering rack. To start, does anyone have any clever troubleshooting suggestions to determine whether it’s the diff or the steering rack making the noise? And further, does anyone want to guess off hand what causes the noise? The car has 50k miles, and I just began to hear the noise. At any less than the sharpest steering angle the noise terminates. Also, it is not only PS pump related, because there is no noise if the car is not moving.
Consider the possibility that the noise is just some “steering stops” rubbing together. Does this happen when you are going over irregularities or on flat pavement. No matter, look under the front end and see if you can see something that find anything that rubs at wheel lock. If you find the spot, put a little grease on it and see what happens.
This has happened to other CRV owners. Replaced the rear differential’s dual pump fluid. It seems to work every time. If it does not, then repost, but I am certain it will.
What is a “dual pump”? Are we talking about simply replacing the differential oil?
Yes, it is simply replacing the differential fluid. The fluid that is used is Honda’s “Dual Pump” Fluid. No idea what the dual pump means, but doing that seems to work. You can only get the fluid at dealers to my knowledge.
Thanks ref. The knowledge on this site is priceless because of the people like you who take the time to share it!
Honda’s realtime 4 wheel drive system uses two pumps and a hydraulic clutch to work. The propellar shaft coming from the transmission turns one pump and the wheels rotating turns another. Normally, they are spinning at the same speed, but when you lose traction, the two pumps will spin at different speeds. This causes the clutch to engage giving you instant 4 wheel drive. As soon as the traction is regained it disengages and you are back to 2 wheel. The transistion is seamless.
To change the fluid, there is a drain bolt and a fill bolt on the driver’s side body of the diff. You can drain it really easily by just opening both bolts and letting the fluid out. To fill it, simply replace the bottom bolt, and then use some tubing that you can route from outside the wheel well down into the top bolt hole. Put a funnel on the end of this tubing and fill the diff until fluid comes back out of the fill hole. According to honda, a fluid change takes 1.1 quarts and the fluid comes in 1 quart botttles so you inevitably need two bottles.
This should take care of the groan.
Back in the 70s the new car dealership I worked in serviced the local police vehicles. One came in with a terrible growling noise from the rear differential when turning corners. It was the first time I’d encountered a problem like that and the noise sounded like all the gears were ground up. I was convinced a full rear end rebuild was needed.
I fully tore apart the rear end only to find nothing was wrong with it. All it needed was a fluid change.
I learned a lot that day.