Ticking Noise Only In Drive

[jkoebel]

My car has, for a few months, had this fairly loud and relatively annoying tick-tick-tick-tick-tick which only happens with the car in drive. It's louder while accelerating, does not happen while coasting, and is barely audible at constant speed. The car is a 1983 240D Automatic, 227K miles.

If I free-rev the car in park or neutral, the noise does not occur. I can't tell off the top of my head if it happens in reverse, but the fact that not in neutral or park seems to indicate to me that it's a part of the transmission.

The tranny hasn't been acting any stranger than normal (still flares 2-3, 3-4 for about 1-2 seconds each, and it'll flare slightly 1-2 if I can get it to engage 1st gear) but the noise is still there.

Any ideas what it could be? It sounds like it's coming from the back of my engine, like right behind my climate control panel, possibly towards my feet. I.e., where I think the transmission meets the engine.

edit:

Exhaust leak from the exhaust manifold gasket. New gasket fixed the problem.

[rrgrassi]

Does it vary in relation to accelerating? CV joints can do that as well. Also check the flex disks and center support bearing

[barry123400]

Try different forward gears if the ticking sound is the exact same speed. Suspect a cv joint.

[jkoebel]

It's always the same interval, varies in loudness only. Constant frequency.

Will try different gears and report back.