hb4

Grade 10. I'll check with the machine shop about the red Loctite - that was the instructions.

Edit: Yes, red Loctite was applied.

checkmate1996

I've posted on this way long time ago...same exact range...replaced TT with Constantine super bearings...problem goes away...

hb4

In somewhat of the tenor of Bill Ball's 'I'm Screwed' thread, I can update the tale for our Gentle Readers.

After finishing with the replacement of Primary Pump seals, O-rings, and torque converter, and reinstalling the trans and suspension we filled the trans; running the engine between reservoir filling.

The first thing we noticed was trans fluid dripping slowly from the tc cover.

The second thing we noticed was that the 3K vibration was still there.

Somehow, the new main seal, PP O-ring, or PP gasket is leaking. So today, with the invaluable help of Thomas, we are taking it all back apart again to try and figure out what happened to cause the leak. We will look for leak paths once we remove the tc, check the OD of the tc snout relative to the ID of the main seal, check for a torn PP gasket, and examine the PP O-ring. Is there anything else that we should look at in there?


After finding the bent vanes in the old stall converter, we figured we found a source for the vibration. Not so, it seems. The only other causes we can imagine are the Torque Tube or, somehow, tuning/bad plug wires. It's hard to imagine that there's something that far out of balance in the transmission itself; it's a pretty hard vibration. Since it's right at 3K, is there any way that the flappy could be causing this?

checkmate1996

Forgive me, but I'm not sure why you have not rebuilt the TT yet. I had the same problem ... put constantine's bearings in and everything was dandy!!

hb4

From Constantine in an earlier post.......

With the botched-up stall converter, I figured we had found the problem, and the condition of the damper, placement of the bearings, runout of the driveshaft (in place), and Constantine's comment all pointed to a good TT.

I was wrong, it wasn't the TC. We will be addressing the TT now.

Black Sea RD

Bill,

Sorry to hear it wasn't the TC after all. Your Supers are being built and we hope they will cure the vibrations.


Brad,

Thank you for the affirmation of our products! Sweet avatar by the way...

Cheers,

hb4

OK, back in and have removed the suspension, trans, and TT. First step was to pull the bearings and damper out of the TT:

Went looking for parts to follow Dwayne's method and found a substitute for the wood spool at Ballard Hardware - the supplier to the Fishing Industry and everyone else in the industrial neighborhood of the ship canal here in Seattle and the antithesis of Home Despot. It's a 2-1/4" coupling and a 2-1/4 to 1/2" bushing. Just right for the TT at 3-5/8" and the bushing passes a 5/8 threaded rod.


Lots of cranking and out they came! The coupling was wrapped with tape to protect the inside of the TT.


The outside rubber part of the bearing holders are like brand new, but the leading damper rubber got distressed by the clamp access hole in the TT. Both bearings sounded gravelly when spun by hand, so I'm hoping this is finally it. I have Constantine's great replacements in hand and will use the same method for installation, one at a time.

Mrmerlin

I would install the damper as well if the rubbers on the ends are good.
Also consider pinning the damper once its installed drill a small hole then install a screw or rivet to just out side of either end of the damper, so it can move but only just..
I know Constantine recommends the damper be removed ,
however I suspect it cant hurt top have it in the tube.
Of course you can install this any way you want

hb4

Well, that's a new option. Here are some of my considerations....

Others' experience with Constantine's bearings alone have indicated success correcting a 3K vibration. Has anyone installed the damper with C's bearings? Did it correct a vibration?

On the other hand, the factory damper seems to be there to take specific frequency vibrations out of the TT by slinging a weight around that has a carefully engineered rubber dampening connection. If the vibrations are caused by the dynamic performance of the driveshaft in the TT, do C's bearings accomplish the same thing in a different manner; i.e., wider bearings, more of them, and a different rubber composition?

Which solution is most likely to avoid having to take the TT back out to correct a vibration, installing Constantine's bearings with the damper, or without it? Do I really want to experiment at this point?

The photo of the extracted damper above shows some distortion of the leading rubber, almost certainly caused by the extraction process. There's also a cut in the rubber where it pooched out of the clamp hole and then back in to make it the rest of the way out of the TT. So there's some reason to reject this damper for re-use in any event.

supercedar

There is no charm in a 3rd time removing the TT. Go with the manufacturer's recommendation and install 3 Super's in the correct location and it will be GREAT! The 3rd bearing replace's the damper for your model car.. The support it gives to that end of the drive shaft will be lost if replaced with the damper. I would like to see a diagram of placement with both damper and 3 Super's if Stan would be kind enough to show.

Thomas

checkmate1996

I didn't have the damper since mine is the long TT setup for a manual transmission... Just 3 bearings to replace. So I can't comment. I would suggest that if it came it with it, I would replace it since you have an auto.

jcorenman

Bill, I would go whatever Constantine recommends. He's looked at this very carefully, and certainly three bearings vs. two changes the situation with respect to resonance. If you were going to simply refresh the two factory bearings, then keeping the ballast-- correction, damper-- in place makes sense. But you are changing the type and number of bearings, so whatever resonance the damper was designed to damp is changed also, and likely not there at all.

Cheers, Jim

hb4

I would never consider leaving out the third 'C' bearing given all of the reports of success with the Constantine product and method.

I can see the logic of Stan's suggestion given that Porsche added the damper to control a vibration of the 4" TT, whereas C's bearings control harmonic whip vibration by shortening the driveshaft's unsupported length and raising its resonant frequency beyond redline.

If the weight of the damper (rather than the dampening effect of its rubber coupling) contributes to controlling vibration, then C's bearings compensate by being the same weight as the replaced bearings and damper. I don't understand how or if adding the additional weight of the damper to C's bearings will affect anything one way or the other.

Having felt the (lack of) vibration in a car with C's bearings and no damper, I suspect that the amount of vibration controlled by the Porsche damper is equivalent to a pea in the princess' mattress. It may be that removing this pea was what Porsche felt was necessary to make the 928 a world class touring car. I will be happy if I can eliminate what is a much stronger vibration at this point.

Mrmerlin

maybe I can say this another way, you will have more dampening available if you fit the factory damper.
Once you get the drive shaft out,
clean it then roll it on a flat surface,
see if its bent,
if its bent then you need another drive shaft

Black Sea RD

We designed the Super Bearings to eliminate the vibration dampener from the TT, dampen felt vibrations and better support the drive shaft. The reason to eliminate the vibe dampener is that they usually break apart with age and cause more problems later.

Putting the vibe dampener back into your TT is your decision. If you do want to put it back in, then you need to place the vibe dampener between the middle and last (trans end) Super Bearings.

Best,