Slight howl in rear differntial

Sounds liike a ring and pinion on rear differential. U can pull the cover off and check this or another thing would be to check your u-joints.

Possibly a bad u-joint or excessive rear end ring/pinion play.

2005 Honda accord hybrid cod p0ac4

Try getting on an open road, get up to about 45 MPH or where ever the noise is loudest. Put the car in neutral and turn the engine off. You can roll in a straight line for a long time. Make sure nodody is around you. If the sound stops when the engine is off, then the noise is coming from the motor. If the sound is still there, its got to be coming from the tires. Id guess a wheel bearing.

HI if the noise comes and goes when you accelerate or decelerate you may be dealing whit the ring and pinion needs adjustment or is going out, remove the rear cover and check for excess metal shavings,Hope this help

sounds like your pressure control solenoid inside your trans is sticking you will have to have your pan pulled and have the solenods checked or replaced since it only fails at times it might check out ok when the pan is pulled.

tranny mount,or drive shaft,also check rear end for leaks and see if its full of gear oil

A pinion seal leaks for one or boyh of these reasons. A worn pinion bearing or a driveshaft vibration, Sounds as though you have both. Do not confuse tire howl with gear howl, be sure.The rear end can run 3 to 500.00 if not more. Ck the gear oil in the rearend for metal content. That will tell you alot. The hard shifting is generally from a sticky spool in the trans valve body. Have the trans serviced w/new oil and filter. The new oil often cleans the moving parts of gum and varnish buildup.in the valve body. One more thing, the rear ends take a special oil and additive if it's a limited slip or posi lock. You will have a popping/binding noise when turning if the wrong lube is install. Have your driveshaft aligned and balanced at at driveshaft shop.or you will end up tearing up the tailshaft on the trans. Good Luck

Check rear axle seal, and brakes.

hi have you checked your wheel bearings?