IRS thump on throttle

[nathanVY]

Hey guys, wondering if anyone can help me figure out what this is. It's been doing this since I bought the car and still hasn't gone away. changed plugs and leads, serviced the trans, etc.

you can hear a muffled thump coming from the rear (auto trans or diff or something in the driveshaft??)
when giving it throttle, either going down a hill or when travelling around 40-60km/h and accelerating.

any ideas?

vs calais with IRS, 180 000 kms.

[VR_Acclaim]

could be diff cradle,unis. gearbox mount

[nathanVY]

how do I check the cradle?