I have a weird whine that comes from drive train as I let the clutch out. It goes away when clutch is engaged. It has been there a long time but is getting worse.
(I have looked at belts, harmonic balance, clutch already.)

I am going to replace the drive line mount.
What size do I need?

Also the Flex joint? Is this an upgrade to some older part? Or should I replace it also?

And also the universal joints. I am not sure what size I need for the the universal joints.

Do I have to measure these parts or can it be figured out from the model?

1990 740 Turbo Sedan Manual Transmission.

Thanks in advance.

The whine is likely the throwout bearing.
Driveline mount; prolly mean the center bearing. I think these came in two sizes and a 90 likely has the larger, mine did.
Flex joint; ??? Do you have a rubber donut behind the trans? I know some cars had those but not many. Ah, stick shift; I think that's the tell.
Ujoints; match listings for the center bearing I believe.

Maybe try some parts places and see what are listed, then ask if not certain?

I had the clutch replaced recently - they did the bearings - as I did have that kind of whine/noise.

When I say whine, it is like rubbing/shudder/squeak - that is what has put me in the direction of the drive line and the center mount and bearing. And universal joints.

Appreciate your thoughts.

It could also be the rear bushings - the Trailing Arm Bushings (TAB's) are notorious and do not last unless you replace them with poly, which some people have bad experiences with.

Anyway, the torque rod bushings could definitely be to blame. I have a looot of slop in my driveline and the Torque rod bushings helped a lot. They connect the top of the differential to the frame to prevent pivot up and down.

Good Luck!

Is it possible that worn rear bushings could create this sound up near the transmission?

I hear this slipping/vibrational rubbing sound (but there is no significant vibration) as I take off in first - and some times changing into second. Just when the load is on and while the clutch releases. I had the clutch and clutch bearings replaced - it was there before and after clutch was replaced.

The sound comes from the transmission area - the front section of the drive line.
I have looked at the universals and center bearing and they seem pretty good.

The gears change good.

Could I need a fluid flush of the transmission?

I have a 740 Turbo manual transmission that has a flex joint - that looks good - and two universals after the center bearing.

I don't think rear bushings are producing what's going on. I think maybe taking the car to another shop that specializes in clutch work and get a test drive, is in order.

I found a transmission specialist who took it for a drive. He felt it was actually the clutch plate squeaking a little - though when he drove it he used the clutch a little differently and the squeak was no where near as noticeable. Probably due to the flywheel needed some attention when I had the clutch changed. He felt no big deal.

Good idea. I will do that.

I found the topic in the FAQ and will work it out.