I had a similar problem with my 95 northstar seville, VIN Y, before it completely died on me. I have no idea what the problem is, but I wouldn't drive it that much unless you want to put a new tranny in (way cheaper in your case...) I also have the invalid signal to TCC code and now the car wont move at all. Of course, the caddy dealership wants $3000 for a tranny with 100k+ miles on it. Im sure you can probably find a nice used tranny for about $200. In my case, I can rarely find one under $1000. If I do find one cheaper, I am skeptikal to buy. I found a tranny on ebay for around $500 including shipping and 1 year warranty ($400 with only 3mo warranty). Does anyone think it would be a good tranny? It only has 55k miles, comes from a deville that was rear ended and was checked before it was pulled out. The seller has great feedback, but I know feedback can be deceiving... I think you should take that thing to the shop unless you are good under the hood. = ) Thats just my opinion though.