it does not make this noise when the engine is cranking over and the car has no loss of power ...but the noise is very intimidating ;as in loud! it is an automatic....any ideas?...thanks,Kris

Check bracket - Tranny to Exhaust pipe. First horizontal section after the pipe goes down.

Will bang like crazy if it's loose.
You can see the bracket if you look straight down, leaning over passenger side of rear of engine compartment.

Then crawl under and try tug on it.
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[aka Sophie's Maintainer] Sven: '89 245, IPD sways, E-fan conversion, 28+ mpg - auto tranny. 850 mi/week commute.

As bliss said it could be center shaft bearing or U joint or check the exhaust pipe at the heatshield. Mine once broke free and slid back under the trans crossmember and thumped like a dogs tail on start up, in rev or at cruise speed..

thanks for the input everyone,this is another $50.00 car ,i feel it has at least that much in parts ,but i want to avoid the tow toll,and am thinking of driving it home,,,,wish me luck...oh, in other volvo news i put the i.p.d. sway bars on my 89 240 and ,oh yeah!, now i know what you guys have been so excited about....kris

I hope it's an exhaust manifold leak. That would be loud.
And less expensive to fix than this story...

I had a loud knock from engine in my '86 245 at about 350K miles.
Turned out to be a head gasked leak from cyl #1 to cyl #2.
Coolant + oil passages were not involved - this was cylinder to cylinder.

Combustion pressure was crossing between #1 + #2 attempting to force the piston against its normal travel. Not good. Probably caused by overheating years earlier; it finally broke through the gasket. Cured with a head gasket + head replacement.
--
[aka Sophie's Maintainer] Sven: '89 245, IPD sways, E-fan conversion, 28+ mpg - auto tranny. 850 mi/week commute.

Does it make this noise when it's idling or when you're driving or both?
steve

both!

Likely a bad center support bearing or really bad U-joint
--
'81 GLT 245 @ 259K; '83 DL 175K