Autobox suddenly gets noisy in lower gears

[Mark Wheeler]

Hi,
am hoping someonr can point me in the right direction on this one. My W210 E320 box makes a kind of wind rushing noise after a few miles, mainly in the lower gears. Seems to be ok in 5th, could this be to do with the fluid level or is it more sinister.
I'm about to take it away on a 500 mile trip so thought I would ask first.

Thanks in advance.

Mark

 

[wireman]

Have the fluid and filter been changed?

 

[alexanderfoti]

Also keep in mind this could be the diff.

Mine made a whooshing noise a low speeds, then the diff packed in

(normally road noise masks it at higher speeds).

 

[Number_Cruncher]

Off the top of my head, I don't know which gear this is on a 722.6, but, usually, one speed in an automatic gearbox locks the gearbox up so it behaves as a simple shaft - no step up or step down of gear ratio.

If the noise disappears completely when the gearbox is in this gear, then, the fault is noise in the mechanical geartrain itself.

For better diagnosis, it is worth checking a schematic of the gear train, and seeing which parts of the gear train locks up in which gear.

 

[alexanderfoti]

Off the top of my head, I don't know which gear this is on a 722.6, but, usually, one speed in an automatic gearbox locks the gearbox up so it behaves as a simple shaft - no step up or step down of gear ratio.

If the noise disappears completely when the gearbox is in this gear, then, the fault is noise in the mechanical geartrain itself.

For better diagnosis, it is worth checking a schematic of the gear train, and seeing which parts of the gear train locks up in which gear.

3rd gear I belive is straight through on the 722.6

 

[Mark Wheeler]

thanks all for your comments. Have been away on business hence the lack of a reply. Now for the curious bit.......started up the beast after a week to find the same louder noise and slightly different pitch as the box went through the gears, however parked up and restarted to find everything back to normal. This would appear to indicate the fault is electrical - yes?

If so where would that point to?

 

[alexanderfoti]

thanks all for your comments. Have been away on business hence the lack of a reply. Now for the curious bit.......started up the beast after a week to find the same louder noise and slightly different pitch as the box went through the gears, however parked up and restarted to find everything back to normal. This would appear to indicate the fault is electrical - yes?

If so where would that point to?

Not sure, it could still be a fluid level issue.

 

[Mark Wheeler]

but did it ever revert to normal like mine has?

 

[Mark Wheeler]

can't see any evidence in the service history and service not due for some 6 months or so. May be worth a try especially as the increase in noise appears to be intermittent, see my earlier comments.

 

[alexanderfoti]

but did it ever revert to normal like mine has?

Mine did not, (but my issue was the diff, not the gearbox, a low fluid level can cause a whining noise)