It depends on what options the 98 and 97 have. If you get the vin # on both cars and call BMW they can tell you for sure if it will fit.
98 BMW maps for dipstick on car free
The 98 Cabrio has a sealed transmission, it does not have a dipstick.
no dip stick. sealed transmission
You normally fill the transmission by way of the dipstick tube.
I know this is not your question, but I bought a 2000 528i with 68K miles in almost perfect condition. So with a 1998 I really would not but anything with more than 90K miles...
the dipstick for the engine is right in front of it, has a yellow handle. there is no dipstick for the transmission.
The automatic trans is a sealed unit with no trans dipstick.
How do I check transmition fluid n 98 vw jetta vr6 2.8
Motorcraft MERCON - V - automatic transmission fluid ( I believe it is stamped into the automatic transmission dipstick )
It's between the battery and the exhaust system, usually it has an yellow handle.
In the same place as the dipstick is located. Use a funnel.