Transmission issues

[acspecialists]

Ever since I changed the oil and filter in my transmission last year it does not shift right. I have since changed the oil a second time to correct the problem. The first time the oil was redline from FCP euro. the second time it was castrol. Both had the correct ratting.

From my research it seems like the torque converter it not locking up. During part throttle acceleration at about 3000rpm the car falls on its face for a few seconds when it should pull hard and smooth. I have added shift modifier both times.

My first and easiest next move would be to as best as possible to fill the transmission with factory fluid? My next move would be to have the transmission and torque converter replaced? My last idea would be to get a low milage 540i sport and put a six speed in?

I love the car but the transmission issue is driving me crazy. If anyone can weigh in on the manual details that would be great. I'm not sure how tough the job would be. I recommendation to a good tranny shop in western washington would also help.

[XAlt]

Check the level very well, could be overfilled.

[jclausen]

It's hard to fill the fluid if the car is not racked and the fluid can only be filled up to a certain temperature. I don't know if the e38 has transmission adaptation values like the newer transmissions, if it did they could be reset.

[acspecialists]

Level is good, I have checked it several times and placed a level on the transmission pan when doing so.

[Old525i]

Was the engine on and the fluid warm when you checked it?

[asianvenom]

I use red line on my 740il with 40k on it and 750il with 10k on it. No issues at all

[Cosmic E38]

I have a sport automatic transmission I pulled from my car to do a six speed swap. Works perfectly.