98 528i Auto trans hard shift???

[AkidsDad]

I have a 98 528i that has intermitent transmission problems. If I am heavy on the throttle there seems to be no problems but if I am stuck in traffic and am staying under 30 mph the shift from second to third can be and most likely will be a very hard shift. Sometimes so hard that it will give me a fault code and I will lose first through third gear. I then shut off the car and wait a few minutes before starting again in which the fault code is gone and I have normal operation once again. The shift from second to third is usually at about 20 mph and I know that it will shift hard when it reaches upwards of 25 mph and harder the faster I go before the shift happens. I will usually shift into nuetral and back into drive in order to avoid this if I feel it about to happen. It will only happen under slow acceleration and only from second to third gear.
There have also been a couple of times where the car will shift out of third as if to go into fourth and nothing happens. I can rev the engine and it won't grab so I again will put the car into nuetral and back into drive and it will resume as normal.
I thought perhaps my fluids were low and they weren't so I took off the pan and drained the fluids and replaced it with no luck although I didn't drain the torque converter.
The BMW shop wants 200 dollars just to diagnose and I can get a used transmission right now for 500 dollars. Or should I just remap it? Im lost

[Lord Vader]

First thing I was gonna ask is of you changed your fluid but I see that you did. It seems to me that your issue Might not be that minor. What I recommend is taking the car to get the OBD system scanned for codes. Their are several codes that will indicate trouble with the transmission but not always set off the check engine light. It could be something that's fixable without even removing the transmission.

[AkidsDad]

I had the check engine light come on about 6 months ago and I used a friends scanner. It had said incorrect 3rd gear ratio.. Still I couldn't tell if that was necessarily mechanical or computer seeings how it's intermitent. That code has not come up since

[Lord Vader]

What was the specific code? Do you remember? Any other codes come up?

[AkidsDad]

Code P0733 Gear 3 incorrect Ratio

That was the only code I have gotten

[Lord Vader]

Battery good? Voltage good? Sometimes if the voltage is low it can cause electrical issues. Disconnect the battery for at least an hour to give the car a chance to reset the computer.

Some people have also reported that cleaning off the rear wheel speed sensor has fixed that code. Most people though said a fluid and filter change helped. Upon further reading it is possible a shift solenoid has failed.

If you can get a working transmission for the car i would take it. If none of the above has fixed the issue, a new transmission may be nessicary.

[AkidsDad]

Thanks for your help with this. I will buy a battery tomorrow and try it out. It might take a few days to see if the problem has gone away but with the car sitting and not being used for a month, the battery is very weak. You called it and I hope thats the fix, seeings its the easiest and cheapest. Well next to the speed sensor needing cleaning.

Again thanks for all your help

[Lord Vader]

Your welcome. Let us know if it works.