TopDownL79

At least it's not the trans...

Hope everything goes smoothly!
I'm quickly learning why Bill Ball is held in such high regard on this board! It's well deserved.

bigs

Hmmm... It is indeed interesting to see all that damage simply from turning into a parking lot.

You guys all know I'm not a wrench, so feel free to have a little good-natured fun with me, but...

If that were a brand new splintering of the TT, shouldn't the splintered metal be shiny?

Bill Ball

bigs - that is weird, isn't it? I saw that shaft 3 weeks ago. Matt saw it. I wish we had taken pictures. I recall it being a normal looking shaft. The break was yesterday, and I agree it looks rusted. All very strange - that area should not. Somebody else will have to explain that.

Matt and I just discussed this, and we agree the camera shots look worse than the actual shaft, but it needs to be looked at more closely when we get it out. Both of us agree we did not notice corrosion 3 weeks ago. Also, this is not an area that gets wet. Hard to explain.

edco

Just got off the phone with Jim @ 928 International

Torque Tube is on order, will ship today or tomorrow - Thanks Jim

Both Jim & Bill recommended the early "Pre 86" thinner shaft type tube as they don't have this weak point at the neckdown like the one in my photos

I’ll get with Bill tonight and see if I need any additional parts

Shmurzik

I second that (for the tenth time)

bigs

Yeah, and even the pattern of the splintering appears strangely uniform. I don't know how Porsche manufactured the TT, but it almost looks like a bundle of individual strips that were joined together and came apart at the seams. And the edges of all the strips seem to be rusted. Strange.

Is it possible for moisture to get inside the TT and partially rust through some "seams" from the inside, such that it's not visible from the outside? Then, perhaps a small bending or twisting of the TT going over a curb might be the last straw.

Otherwise, I'd hate to think our TT's could be shattered by such minimal stress!

Bill Ball

I'm going to take it easy pulling into parking lots from now on.

I'd like to see some other photos of broken TT shafts. I recall seeing broken manual tranny input shaft photos and the break was ragged but clean and shiny.

This does look to a layman (like me) to be delamination. Some of the metalurgists here can tell us how twisted shafts fail. Even if we just didn't notice the corrosion 3 weeks ago and this thing was trashed and ready to give up, how does that happen in a dry spot in a climate that is free of road salt. Maybe the car sat in flood water at some point, but I don't recall anything else that would indicate that.

Jim bailey - 928 International

The ones I have see have nearly always "delaminated" into a bundle of square long strings then twist off just as shown. One bent torque tube housing did snap the shaft cleanly but that was a different kind of stress metal fatigue. Customer bought a used tube from a wreck (not from us) and only later discovered the tube was bent in the crash.

BC

If they fail this way, then would a nice tight collar around that area not improve the strength and breaking point of these shafts? (lots of owners getting up to 500hp)

bigs

I think it would be fascinating, when you pull the TT off, to inspect the inside for rust. My feeble mind can't imagine any other way you would have this appearance except for rust weakening the laminations from the inside. Cuz it sure does appear to be a laminated tube.

edco

I just went and took a look at it again, the photo makes it look more rusted than it actually is. I will take photos of it up close in natural light when we get the TT pulled. It looks more like it got hot then rusted up close in person

All the parts are now on order, including the torque converter bearings and Sleeve

Jim bailey - 928 International

Generally speaking a collar will simply move the stress to where the collar ends. The shafts are made of "solid" steel but as has been discussed in the past the shafts twist torque under load and the outer diameter moves a different amount than the core of the shaft and that difference in movement seems to allow for the development of the square strings.

Nicole

And I third it...

IcemanG17

I also vote yes on the "Bill Rules" sub topic

Edco
Man that sucks....it weird how it rusted from the inside.....its one of those things "WYAIT"....rear main seal would be easier...torque convertor bearings....you get the idea....

I will volunteer to help out during the TT PARTY!!!!!

Ed Scherer

Well, that certainly looks strangely familiar. Happened to me about 5 years ago.



[Click any of the photos for the big version]

Mine also happened at slow speed. Slowly pulling away from a stop sign in my own neighborhood.