Can anyone offer any ideas how I could test the auto box on a 740i E38 (1998) BMW. I've read that they are "sealed for life" by BMW so even if you have a full BMW SH they never change the fluid but specialists do it ever 60k. If its not changed they can fail at 120 to 150k miles. This car has less than this but I don't know that much about automatic transmissions so any specific / generic tests to assess its health would be really appreciated.

TIA.

The only real way is in drive with h/brake and foot brake applied and take it to 2500rpm for 20 secs, in neutral for 20 on tickover then same in revervse. If it the drives okay immediatly after then it is okay, if it's sluggish or hesitant then it's not okay.

I believe its fitted with a ZF auto box, something to be wary of.

Never rev it in neutal or park, this can blow out the input front seal..... If you have a google lots of warnings about this as some states MOT type tests require high revs which got very bad press. Some refused to do this element !

Yes you can change the fluid, they take dextron III, should be the same as fitted in p38 rangerovers (except of course it will not have a transfer box bolted on the back) so you can get filters etc.

60,000 sounds about right for all fluids, when I did mine the car became quieter and smoother, as its a partly electronic box normal tests such as handbrake on do not apply to such a degree, if its always a harsh change this could be a poor connection.

Regards Mark

If its a '98 then it is a fully electronic box. I have a '98 728 with the 5 speed ZF box (148K miles). Its fully electronic and the only problems I have had have been due to a faulty engine sensor. Using the 'steptronic' shift it had no problems, in 'D' it would change down when the engine misfired. Every change up/ down is the result of the transmission ecu evaluating the (many) sensors.

You can also tell alot about a auto box by the oil colour, if its a nice clean red colour then there is a good chance that all is well, if its black and smells orrible then all is not well.
Steve.