Hey guys just a quick question, maybe you've run into this before....
My 850 runs like a top now, except for the rear seal leak....
When I put the car into drive/reverse, the engine compartment makes
a louder sound. Almost like a rattling exhaust pipe....As soon as you take it out
of gear the noise goes away. In park I can rev the engine and no noise.

 

Greetings from Chicagoland.

Just a guess, but have you checked the engine mounts? The pax-side mount gets weak before other mounts do. When the tranny is engaged, the engine is under load and may get "twisted" a little, and engine might be rubbing against the sub-frame.

Take a look at FCP Groton's parts illustration. The part #9135178 is what I'm referring to (in fact, I just replaced it a few days ago).

http://www.fcpgroton.com/volvo850mounts.htm

The mount actually has a wear indicator. There is a probe sticking out of the holes on the side. If the probe is low (closer to the sub-frame), you need to replace it.

If this isn't the case, have someone look at the engine compartment while you shift into gear (use park-brake and wheel chocks to avoid running over the person).

Best wishes,



JPN