I have a 1999 Chevy Lumina with 70k miles on it. One day on my way to work I noticed that when I accelerated after stopping at a light the car would not move for a moment, then violently kick into gear. I tried manually shifting the gears, and it drove just fine.

I drove it for a few days shifting the gears manually while I waited for my paycheck and looked around for a good place to get the transmission looked at. When I had the money, I started driving my car out to the shop, but halfway there my car stopped shifting gears entirely, and I had to have it towed the rest of the way.

Today I got my car back, and they told me they rebuilt the transmission. I noticed immediately that it was not automatically shifting when in drive, but was shifting manually just like it had before it totally quit working. The mechanic told me it was just the governor, and it should unstick if I drove it around manually for a bit.

Because this is exactly what it was doing just before the transmission went out completely, I am worried that driving it around manually is just going to make the transmission go out again and I will be back to square one.

Is there any validity to what he is suggesting? Should I just drive it around for a bit, and trust it will take care of itself, or is this just a bunch of BS from a bad mechanic?