The tranny and transaxle are the same component. The transaxle is the correct term since it incorporates transmission and the final drive. The front pump is in the transmission. Did you hear the noise before the transmission oil was changed? I would check the oil level. Drive car for 15 to 20 mins to warm the transmission oil. Park on level surface with trans in park and engine running. Remove the transmission dipstick and wipe off the oil. Put dipstick back and wait a couple of seconds and then withdraw. The level must be in the crosshatched area, too low or too high are problematic.
The exhaust moves differently when the car is under load. The engine/tranny/exhaust is rotating forward and backward against the resistance of the mounts which causes a very large amount of movement at the end of the y pipe where it meets the flex pipe. The flex pipe absorbs this excess movement on front wheel drive vehicles. No flex pipe on rear wheel drive vehicles.
The engine mounts are oil filled and susceptable to failure which will allow the engine and exhaust to move a lot under load. You can check for a damaged mount by applying the brakes and accelerating the engine in drive (not too much) while someone watches the engine pitch forward.
Look for loose brackets, heat shields, or the exhaust touching something. | 
