I have strange problem with my transmission. After driving away from a store it never shifted into O/D. Which was strange because it was working before i parked to go inside. Then, after about 10 minutes on my way home, it had to rev up to about 3000 for the transmission to shift at all. I let it sit overnight, hoping that maby it would work temporarily in the morning (before the transmission fluid became hot) to make it to an appointment. However it still needed to reach 3000 rpm to shift, which did not surprise me. What did surprise me was that on my way home I went over some railroad tracks, and the transmission started to shift normally again.

Now, I do not know much about transmissions, but I have a few ideas what it could be and would like some input.

- Possible loose vaccume line.
- Poor ground wire.
- Clogged transmission filter.
- Loose sensor wire.

The transmission fluid is still a good colour, and was changed within the last 15 000 kilometers.

Thank you in advance for any help.