97 740iL engine noise

Recently bought 97 740 iL. Knew it needed valve cover gaskets and a repair of a vacuum problem. Both fixed. I'm getting a whine which seems to come from the front portion of the engine, but is difficult to pinpoint. Sound is more pronounced in D than P. Goes away in N. Also goes away when engine speed goes about 1 K RPM.

I've read a rear main oil seal failure can cause a similar sound, and I've tried opening the oil filler cap when sound is present. This did not make the sound go away.

Suspecting fan clutch, hydraulic pump or power steering pump. Any ideas would be greatly appreciated. Worst case, I'm concerned this could be a transmission problem - - the sound doesn't bother me too much unless its a sign of a significant problem.

Again, thanks in advance for any help or ideas anyone can provide.

Not that I know, but it appears to me that this might be a tranny issue. Have you had it checked?

There is a filter at the firewall between the engine and transmission. It's very hard to get to. If it is clogged, it will cause your transmission to make a loise. It can get really loud. I had mine changed and was greatfull it was not the transmission.