Greetings everyone - while I know this question has been addressed in other post I have yet to see anyone post the fix ... so here is my troubles and maybe someone could help.

1994 940 Turbo wagon 198000 miles ...

I can floor board the car and not experience this fluttering from rear end if there is only two people in the car. If I have more people in the back seats or heavy load of stuff in cargo rear the noise will show up.

The noise feels like someone is hitting the rear of the car with a rubber hammer .. it is not a metal sound ... and it only does it when pulling off from a stop .. at some periods it will show itself more making a right hand turn .. but mainly from pulling off from a stop.

Also, when coming to a stop and letting off the brake I get a thud sound hard to explain but I am sure this also is related in nature to my other problem

I hope someone has some idea or maybe had the same troubles and could post what repair I need ...

Thanks in advance.

 

Either you or a mechanic will need to physically examine the underside of the car. The noise could any or a combination of the following...and possibly some other issues I've left out. Someone will no doubt add to the list.
1. Sagged motor/transmission mounts allowing the exhaust line to contact the body. Could also be failed exhaust line mounts towards the rear of the car.
2. Bad trailing arm bushings.
3. worn center drive shaft carrier bearing mount.
4. Bad U joints.
5. Failing rear differential.

 

I vote for #3.

 

It seems like it has to do with suspension height .. more weight lowers the angle perhaps of the drive line ... but with only two people .. you can go from a dead stop to wide open and no flutter .. but you add weight and it starts .. I guess from what I have read the support shouldn't have much movement, correct? should be pretty stable?

 

Correct. The rubber doughnut fails and splits/cracks and allows more motion than needed. Aftermarket seems to use inferior rubber; IMO go w/ genuine Volvo. Still, failed engine or trans mounts can alter driveline angle as well.