My E350 2006 don't go over 40 mpr and don't switch

had similar problem with my ford behind the dash there is a little elect. motor and gear box that moves the dampers the gears have broke they are plastic

you're on the right track. it sounds like the right wheel bearing is causing the noise.

Throttle position snesors don't make noise. Please have a local shop liten to the noise you say that you hear.

Problems with cv joints can cause this noise when turning, stopping. Eventually the joint just gives way and you go no where!

I dont know how you figure its the brakes, do they get hot and seas up??? if they do then bleed the system. Maybe and maybe you or some one else might have aded other oil other then brake fluid, or there is moisture in the system.

This is noise caused by gear roll over, in modern manual transmissions a very thin lube is used, in most it is just regular ATF not the must thicker gear oil so this roll over noise is made worse. This noise is to some irritating others don't seem to notice. This noise doesn't affect operation of the manual transmission at all and even if you replaced all the bearings and gears in the transmission it would soon return as things wear in and loosen up. If you switch to a light gear oil it will make the gear roll over noise quite down but the transmission will be hard to shift cold.

I would suspect it is a wheel bearing issue, if it sounds similar to a baseball card in the spokes of a bicycle, stays somewhat same pitch just louder with speed that is where I would look. Does noise go away or change when making turns?

Hello, Thought to have the differential lube checked? I had a 1994 Crown Vic and it had 161,000 miles on it when I sold it.

Although you need to reduce the overall speed, try turning your Overdrive button off and see if the noise goes away. The overdrive kicks in above 42MPH and if that is when your car starts to grind, its a good possibility for trouble.

Aside from that, the 3rd and 4th gear synchronizers or gears could be going. You could pull off the trans pan and see how much metal is in the pan.

You won't be going much longer if it is making this noise. Also try car-parts.com for Salvaged parts. It has an instant request feature and gives pricing, location, warranty, and contact info for all types of parts.

Vibrations usually don't make noise BUT, a bad hub bearing or a differential that is severely worn can.
Bearings generally don't both fail at the same time so if you hear the noise on one side more than the other, likely that one has failed. You should also check the diff fluid level. (low lube level will quickly destroy the gear set) I'd go as far as removing the cover and checking the gears and looking at the lube itself to see if it has any metal in it.
I could tell you much more by driving it but obviously I can't do that!!

Sounds like a problem with your transmission, may be caused from lack of oil. Make sure there is enough auto trans fluid by checking the dipstick.