vibration on grades

[pammiesuesguy]

Hello, I'm new to the forum.
I drive from Northern California to Medford Oregon twice a month over the Siskiyou pass. About 1\2 way up the grade either way a low moaning vibration will happen. It sounds as if it is behind me but can be felt throuout the car. If I drop down a gear it quiets down but is still apparent. As soon as you top the pass and start down hill it disappears. At no other speed or situation does this happen, only when driving on a long uphill grade.
The car is an 06 Turbo automatic transmission with 105K miles.
Rich

[bajaguy]

Sounds like what I had with my U-joints. Unter load or torque it would be more appearent. They were just old and didn't move freely.

[pammiesuesguy]

Do you mean the ujoints in the driveline to the rear axle?
Rich

[bajaguy]

Yes. It's worth looking in to.