Sorry if I missed it but after several searches I could not find anything on point.

The Problem - When I shift into reverse and begin to back up, the transmission will 'jump' out of reverse and suddenly bang back in and sometimes out again.

I notice this quite a bit. I took it to a Transmission Specialist place and after a road trip the symptom could not produce. Problem continued to occur.

I was at an independent 'fix anything' type garage and the guy noticed while this symptom presented that the reverse indicator would flicker. He said it was an electronic switch located on the transaxle that was the culprit. He said the part alone was about $125 and to leave it until it breaks.

Does anyone know what part he's talking about?
Does this sound like a cause of the problem?
Is this something a DIY could undertake?
Is this something Auto Zone etc. carries?
And lastly, is this a common problem?

I'm counting on you guys!

'01 ES300 93k recent 90k service

 

Usually you guys jump right on things but this time I got skunked. No suggestions?

 

I don't know if this transmission uses a cable, a linkage or both to connect the shifter to the transmission, but it sounds that it is out of adjustment, not permitting it to enter reverse fully.

The could also cause your back up lights to flicker. I assume your garage was talking about the backup light switch, and I'm also assuming its an Automatic transmission.

If I'm right, than its just a simple adjustment.

Phil