engine reving too hard at 100km

[sheer1]

hi all, new to this. Have a 1987 BMW 735i, auto.( australia) It is reving at 3000rpm at 100 km, or 60 mph. I had gearbox serviced and they said it was all ok, car is driven in econ mode but is still reving way too high, any ideas why this might be. im sure this cant be right, thought it should be reving at around 2000rpm.any help is appreciated

[lincolnmaster80]

My V12 at 110 KM/h (about 70mph if I'm not mistaken) rev's at about 2500RMP. It'll go up to about 3000-3500 RPM when I pull the SEM switch into M at that speed.

All I can suggest is count each gear change from stop to highway speeds. If you count two changes, it is in 3rd gear. 3 changes means 4th gear (overdrive) is engaged and the transmission is working fine.

When you back off the throttle, does it decelerate as per normal?

[sheer1]

Originally Posted by lincolnmaster80

My V12 at 110 KM/h (about 70mph if I'm not mistaken) rev's at about 2500RMP. It'll go up to about 3000-3500 RPM when I pull the SEM switch into M at that speed.

All I can suggest is count each gear change from stop to highway speeds. If you count two changes, it is in 3rd gear. 3 changes means 4th gear (overdrive) is engaged and the transmission is working fine.

When you back off the throttle, does it decelerate as per normal?

thanks for that, worked out it is not changing to 4th when hard on throttle. Also told to disconnect battery for 20 min so resets trans computer etc, seems much better now, think trans computer was part of this problem, i dont drive car hard so happy as it is now thanks.

[lincolnmaster80]

Originally Posted by sheer1

thanks for that, worked out it is not changing to 4th when hard on throttle. Also told to disconnect battery for 20 min so resets trans computer etc, seems much better now, think trans computer was part of this problem, i dont drive car hard so happy as it is now thanks.

If the magic reset worked, then it's due to two things...well, three actually. The first two are week alternator (or voltage regulator if that is just replaceable) or battery needs replacing. The third is sometimes the car can get itself into a sort of lull... In that case it would be good to pull the codes and see what's going on cuz sometimes a small part isn't functioning properly and the issue MAY arrise again.