97' 528i auto trans shifting problem, stuck in 1st
BMW is a 1997 528i, auto transmission about ~180,000 miles. Couple years ago when the car was at 100k miles, tranny was giving me some slipping issues as well as getting stuck in S3/S2 when it would rain/snow. At that time, a shop had added some non slip oil to the trans, which fixed the problem for the most part. Another mechanic had told me that the selector sensor located on the side of the transmission has gone bad, which is why it got stuck in S2/3 when it would rain/snow because moisture in the air would freeze the sensor. Though he sounded right, I never replaced that sensor.
At this time, the BMW will not shift out of 1st gear. For the past couple months, the tranny had been giving me slipping issues again, for example, when I would brake, make a left/right turn, go up/down a hill, or accelerate quickly the car would slip in and out of gear for a couple seconds and then knock back in. From my understanding, this means that the trans fliud is low, since sudden jerks/movements while driving would cause the little fluid thats left in there to shift from side to side, making the gears slip in and out.
Unfortunately I hadn't taken care of that problem since, and now the car will not shift out of 1st gear no matter what. Haven't been able to check the codes yet since the nearest autozone requires driving on the highway, but the check engine light is on (has been on for some time now, even before this problem)
Anyway, while driving if I keep the car in (D) Drive, i'll get halfway up the road and when I hit about 3-4k RPM (in first gear), the tranny will slip and the RPMs will rev very high until I let off the gas. At that point the car will not return to 1st gear, and the Transmission? light will come on (not check engine & not traction control, but it's a yellow light on the far right side that looks like a circle) and I have to shut the car off for about a minute and turn it back on before this light will go off and it'll go back into 1st.
So, instead of putting it in Drive, i'm having to put it in S1, which will obviously not let me go over about 25mph, but, the transmission doesn't slip at 3-4k like it does in D. This way I can avoid having that light come on and turning the car off and on.
Also, shifting into S2/S3 will still not let the car shift out of 1st. Reverse, Park, and Neutral all work normally with the correct letters appearing in the dash.
I'm really hoping that the tranny is not done for good. Being on a college student budget, maintenance for this car has just been eating away at the money i've attempted to save. What should I do in my case? Someone had suggested taking it to a tranny shop, and having them drain and fill the transmission fluid to start off with. Do you think this would solve my problem?