I'm curious...At what mileage does the TT usually goes bad? Is it more of an age related problem or a mileage problem? Azir's started at 90K where as mine started at 75,000. From what I've read, it seems most do go around 80 - 90K. Anyone else want to post their TT problem mileage??? My car sat for a long time (basically abandoned) before I got it so I think that may have something to do with mine going at 75,000.

 

My TT noise was evident around 110kmiles.

 

TT noise seems to occur typically between 80,000 miles and 120,000 miles lowest was about 60,000 miles and the car belonged to Mark Anderson at the time . It is probably RPM related so cruising the interstate in 4th gear at 2,500 rpm is much different than hitting redline in second gear . We have no definitive answers about how and why simply deal with the results ; offer the rebuilt tubes for $495 exchange . We always recommend changing the torque convertor bearings $26 times two while the transmission is out of the car and sometimes it is these bearings which fail first and transfers more load and vibration to the torque tube bearings , carriers and shims . The driveshaft inside the central tube can be moved rather easily and this can occur during shipping a couple taps with a rubber mallet easily relocates it .

 

Thanks Jim.

Hi Sharks,

From what I can find, there are no stops for the bearings. The TT looks to be perfectly cylindrical. Therefore, you just tap the bearings down the TT to a position where the old bearings were. Until someone provides more procedures and specifications, that is my best guess. See the following link for TT rebuild procedure. I see no mention of greater clarification.
<a href="http://home.attbi.com/~gq-beej/928/ttrebuild.htm" target="_blank">http://home.attbi.com/~gq-beej/928/ttrebuild.htm</a>

Anyone have anything more specific?
<img border="0" alt="[burnout]" title="" src="graemlins/burnout.gif" /> <img border="0" alt="[jumper]" title="" src="graemlins/jumper.gif" /> <img border="0" alt="[burnout]" title="" src="graemlins/burnout.gif" />

 

OK Guys, I have the exhaust unbolted from the headers but the O2 sensor cable is so short that I can't get a spanner to the sensor to unscrew it. How do I locate and unhook the O2 wire from the passenger side footwell so that I can get some slack ? Does the cable come into the car ?

Thanks. Azir.

 

Hi Azir,

I would keep the exhaust jacked up as high as possible to keep from fowling up your sensor connections until you detach the sensor. The attached wires are special heat resistant types. You should not cut or splice them close to the exhaust. My mechanic had a special slotted socket to remove the sensor. At $113 be very careful with the sensor. The Big 3 should know about and/or have the socket.

The connections go toward the fuse panel. But, I do not know how to identify them.

<img border="0" alt="[hiha]" title="" src="graemlins/roflmao.gif" />

 

Thom,

Which fuse panel ? Is it the pabel on the passenger side foot well ?

87, 928S4, Auto.

 

passenger floor, behind carpet, at lower firewall, only fuse panel

 

Just because the noise is from the torque tube area doesn't mean it is the torque tube! My '83 started noises and it sounded like the torque tube. My mechanic says it is very difficult to diagnose because bearing noises travel along the tube.

In my case, it WASN'T the torque tube; it was the two bearings that are just behind the torque tube (in the front part of the transmission and one that is pressed on the shaft just in front of the flex plate that connects to the torque converter). The torque tube bearings spun smooth and had no noise.

The labor is more, because it is a pain to remove the front of the transmission, but the bearings are relatively inexpensive (~ $55.00 for the pair).

So if the torque tube bearings aren't bad this is the next place to check. Also, since you're that deep into the drivetrain, you may as well replace those bearings while you're at it.

Good luck ...

 

Hi Thom,

You seem to be familiar with this, how do I identify the sensor wire in the foot well ? is it the one with the round long connector resembling an radio antenna connector ?

Azir, 97, 928S4, Auto

 

Azir, Do not do the repair without doing the converter bearings!!!! You may ask why....I had to do this job twice as the first time I was in such a rush that I didnt bother to find someone with a press to put the bearings on the torque converter. The sound DEFINITELY travels the length of the tube as it sounded like it was coming from the front bellhousing. Live and learn but do both jobs while youre in there...Good luck.

 

Hey Azir,
Just cut the wires to the O2 sensor as close as possible to the sensor itself, being sure to leave enough cable to properly solder and heatshrink the wiring back together afterwards. Trying to fish out and fish back in the cable is a PITA. I changed my O2 sensor and thats what I did - no probs...
I also used a universal sensor I bought from 928Inter. for small change so don't be too alarmed if it gets FUBAR....

FYI - Remove the lower part of the fuse panel (thin strip of wood held on by 2 phillips head screws). The sensor connector lives close to the floorboard and yes, it does resemble an antenna connector.....

Cheers

 

Update !

Both Transmission and TT are out of the car as of one hour ago, The Torque Converter bearings are the culprit, however the TT bearings are not too far behind. Tomorrow I will take both the TT and the Converter Housing to a local transmission shop, hope they will be able to put in a set of new bearings.

Azir. 87, 928S4, Auto.

 

What makes TT Bearings fail? Heat and age.

The grease goes stiff and the transmission (heat) and the front bearing (Cat heat) are most susceptible.

The bearings are not sealed. They are shielded, both sides, like an inline skate bearing. It is possible to lube them, but why? They are in the range of $25 each new. They do not have provision for greasing (Perhaps they should - retrofit) Then again fresh bearings every 10-15 years is not such a bad deal.

My GTS had a new tube installed for ridiculous cost at 50,000 miles.

The AT tube "steady" bearings & holders are equally spaced (roughly) between the front and rear drvshaft connection points. There is a damper a deadweight at the end of the shaft to counter low freq resonance.

Rebuild is easy, but you'll work up a sweat - takes about 2 hours to do once you've done one. I've done 3 here, and many shops are happy to do it for you, if they have the knowledge. Some don't. A rebuild kit would be great since it would save a lot on shipping heavy tubes and the delay factor. There are little metal/rubber bearing bushings that can wreck in the process, then you have to get creative. A kit with jigs, documentation & bearings could be marketed for &lt; $99.

 

Hehe, I was going to chime in and recommend the write-up on the TT rebuild procedure, but PeteS somehow already had my link? I'm glad that its getting use though, and a VERY special thanks to David for documenting his work so we can copy it and save ourselves some $$$. Azir, I hope you get it squared away soon! It really sucks not being able to drive your 928, I think we all know from experience. Thanks PeteS for posting the link!