V8 tranny in limp mode

[Zsolt]

I am posting this for a friend who has a couple 90 V8 Audis.
Any suggestions?
Thanks,
  Zsolt

Well the car sometimes goes into "Limp" mode , only stays in 3rd gear.  It only does this when the engine is very hot and I let it sit for a few minutes i.e parked.  When I start it up again and continue on, it goes into limp mode.  If I turn off the car, and restart it, everything is back to normal for a few minutes, then limp. If the car sits for a long time (cools off I guess) its fine.

I replaced the bulb in the switch a few months ago and wonder if I "loosened" or buggered something. I read with interest Joe Griffith's thread on the Audifans site on July 03, 2002.

Same problem, but no results were posted. http://www.audifans.com/pipermail/v8/2002-July/008642.html
I'm assuming that i can take it out and clean it, but as a last resort I'd like to know how much these units cost.