1991 525i with hard shift after trans rebuild. What a story.

[stavronis]

I bought a ’91 525I from a small local dealer. After I got it home, I noticed the transmission was leaking. I took it back several times to fix the leak. After several attempts to find the leak, a quarter-sized hole was discovered at the top of the trans.
The owner of the dealership agreed to split the cost of having the transmission rebuilt or replaced. He had it in his shop for a little over a month. During that time, he ordered a rebuilt transmission, installed the transmission, and sent it to the local BMW dealer for programming. He told me it would shift hard for about 300 miles and then smooth out because of the new springs, etc in the rebuilt transmission. It did what he said, but after a few more miles, I noticed it was leaking again.
I took it back to my dealer. He took it to one of the satellite shops of the transmission shop where he bought the transmission. They didn’t find a problem and gave it back to me. The leak was gone (I don’t know how that happened), but it was shifting hard again. I let it go for a few hundred miles to see if it would smooth out again and it didn’t. I took it back to my dealer again.
He contacted the main shop and they agreed to look at it. They found my dealer ordered and installed the wrong transmission. The transmission shop got the original transmission back and rebuilt it. However, after a month and hurricane Charley, they told me it may never shift properly again.
I took it back to my dealer and he said he would look at it. He did and he said a little positive shift isn’t that bad as long as it’s working. It shifts hard (there is a clunk or a bang) going into second, a little harder going into third and when it downshifts to first. When the car is cold, it will stay in first for quite a while before shifting to second.
My question is does anyone have any idea what might be happening? And, if the transmission is rebuilt, why doesn’t it work properly?

[632 Regal]

if its the original trans again and they sent it out for the computer to be reprogrammed, then you probably have to have it reprogrammed back to where it was... confusing story actually but from what I read sounds like it was programmed for the wrong trans.

[stavronis]

This is my first post '80s BMW and the first my first automatic, so I still have a lot to learn about this particular car. Thanks for the advice. I'll talk to the local BMW dealer about getting it reprogrammed.