Auto 'box sticking

[davog]

I have an '89 530i auto. It has started to stick in 1st when its cold and wont change up. If you put it in manual and move the selecor, it tries to change but then goes back to 1st again. After a few minutes of this, it will change up and be fine for the rest of the day.
Are there any sensors/switches i should check?
Thanks

[632 Regal]

sounds like the slushbox is giving up the ghost on you.

If I was you I would change the filter and add the right fluid til its full again, no flush no messing around and see if that helps. USE THE CORRECT FLUID!!!

If it does help then later after about 5-10k miles drain the pan and add again, no sooner or you could waste the trans if it isnt already toast.