supercedar

Bill,

Might want to consider keeping the damper in the tube along with two Constantine bearings. Looks like Porsche wants it there.
Thomas

hb4

It does raise that question, doesn't it?

Black Sea RD

About the vibration dampener.

We designed the Super Bearings so that three replace the weight of the vibration dampner which shouldn't be re-used with our Super Bearings. The vibration dampener can come apart with age and cause more problems in the long run.

Our website has a section just about this very issue and pictures of a broken apart vibration dampener.

Cheers,

supercedar

Are you saying we should not attempt a NEW dampner with two Supers?
Thomas

Black Sea RD

Three Supers is the better way to go.

The drive shaft will also be supported better.

supercedar

I love Super!

hb4

Well, we removed the transmission last night and had a chance to look at things.

1. We found that by spinning the flex plate after removing the TC cover that the flex plate shaft (TC cover) bushings were noisy and rough. Would that cause the 3K vibration, or should I expect the vibration at all RPMs?

2. With the TC cover removed but the pump still in place, when we spin the input shaft we hear a rubbing sound near the front of the transmission (inner shaft in photo below). It is also 'loose' radially in that the end can move around a little. Could this be the K1 clutch rubbing on the B1 band since it's impossible to spin it exactly concentrically?

3. Looking into the back of the TT, the vibration damper is about 4" back from the face of the TT flange, and appears in great condition. The shaft is firm in the Tube, and the damper seem seems tight. In the last photo you can see a smooth, clean area on the inside of the TT just aft of the damper. Would that indicate the the damper has been moving? It's hard to imagine a scenario where the damper was installed too far from the front and driven back to the present location. Wouldn't it have been installed from the rear? (This is a replacement TT, 33K and 10 yrs ago.)

We're going to remove the pan today and see if there's any debris, plus disconnect the front flex plate to spin the shaft and listen for any bearing noise.

Bill Ball

Possibly. Replacing the two bearings is straightforward and should be done.

Correct - you cannot evaluate it this way. You need to stand the tranny on its hind end to seat the input shaft assembly, then spin it. Since it is not supported at the front right now, expect some play. I gather you are going to pull the primary pump and do its o-ring and seal. You should measure the end clearance in the K1 pack - should be about 1mm - then take it apart and examine the friction plates for wear and the metal plates for burn spots. Replace as needed. Examine the brake band as well. Even at 239K miles, and not babied miles, my friction plates were good, but I replaced them anyway. The metal plates had very few burn marks so I left them alone, and the brake band was fine. I've seen a much lower mile tranny where this was not true.

Constantine should answer this. It sure looks fresh in there. So, you did not remove the TT from the bellhousing. I suppose you can still evaluate the bearings. The shaft should spin quietly with some drag from bearing grease (not freewheeling or noisy). It should spin true. There is a runout and play spec in the WSM. Mine was still remarkably firm, quiet and perfectly centered even at 239K miles. - I know that is an exception.

dr bob

On similar but non-928 cars, I've seen the driveshaft bent slightly when it isn't R&R'd carefully. It's way yoo easy to let one end of the tube hang by just the driveshaft at the other end. Since you have the shaft out on the floor, put a dial indicator on each end and look at radial runout numbers. It doesn't take much at all to generate the vibrations you describe.

hb4

We removed the Primary Pump and see some things that don't look right. In the photos below.....

1. 'Dashed' marks on spindle

2. Wear marks on end of spindle. Is this the thrust washer? If not, is it shown or missing?

3. 'Dashed' marks on piston

Black Sea RD

The vibration dampener is a too far toward the transmission side, it should be approximately 15+ inches from the transmission end, toward the engine.

The good news is the dampener is the newer style which seem to hold up a bit better than the older style.

The not so good news is that they are not as easy to move around with the drive shaft in the way. The outer rubber is a bit softer and tends to rip and/or come off the vibration dampener if not done carefully.

Good to hear the TT is in overall good shape!

Good luck with the transmission investigation.

Cheers,

supercedar

Bump

hb4

Now that the transmission is out of the car, the answer to my 'what's next' question is......

1. The Torque Converter is going to the rebuilder tomorrow for inspection and possible re-build.

2. We're looking at the primary pump and hoping for some feedback from some RLers on the 'dashed' markings. Could these point to the source of vibrations?

3. We found the TT damper out of position but in good shape.It (or was misplaced) 4" from the trans flange rather than what I've heard should be something like 12". Would this cause a vibration? Tangentially , does anyone have the correct dimensions for the placement of the bearings and damper for a later automatic?

4. Measuring the runout of the driveshaft is next on our list.

hb4

Think this would cause a 3K vibration?

jcorenman

OMG, You've let all the magic out!!

Seriously, What is that, that we are looking at??

Cheers,