Porsche Repair: 944 S2 Torque Tube Repair, devil s advocate, torque tube

Question
Dave, I just picked up a 90' 944 S2 Cab. 51k.  During the initial check up at my local shop my mechanic indicated the bearings in the torque tube are shot.  What are my options?  Can the bearings just be replaced or do you do the whole tube.  What can I expect either in labor hours or dollars from this job?  Thanks so much for your time and expertise.  Drew

Answer
Drew, first...what a gorgeous car.  Great choice!  Second...good job.  You've asked a question I hadn't gotten before; and even though my daughter owned a '91 S2, I hadn't had the "opportunity" to make this repair for her.  

Obviously you're asking these questions with the machanic's repair estimate in your hand...I'll bet it's a staggering number....especially for someone who expected a car with 51,000 miles to be "like new".

Let's review:

The torque tube is basically a rigid housing comnnecting the 944's bellhousing (clutch housing) to the transaxle at the rtear wheels.  Inside the housing is a driveshaft supported by three or four ball  bearings. Over time these bearings can expire and require replacement.

First, I'm somewhat surprised the bearings are 'shot' at this mileage.  But could happen I suppose.  Second, I wonder how the mechanic made this diagnosis.  This is the part I hate.  Your trusted mechanic, who has seen and touched your car is over there.. and I'm over here second guessing.  Not nice.  But sometimes it's fun.  So, I mean no diseaspect to your mechanic, but as a devil's advocate...think about this:

From a good source: "Check the condition of the torque tube bearings while the torque tube is pulled back by placing the trans in neutral and spinning the input shaft with your hand. The shaft should spin freely without any "grinding" sensation; if there is a grinding  sensation like a worn bearing, then the 3 bearings in which the shaft is supported are probably bad and will need to be replaced."

So your mechanic had the car on the hoist and so far apart that he (or she) was able to make this test???  Spinning the input shaft in the torque tube?  How much did your inspection cost you?  Just how did he come to this diagnosis?  Another possible way would be the "marbles in the rear end test".  When you drive the car there are very noticeable clacking sounds of metal ball bearings slapping at each other.  This could very well be the torque tube bearings, as diagnosed, or it actually could be a couple other very bad things...but do you hear and does your mechanic hear the marbles when driving the car?

I have some specific instructions how to replace the torque tube bearings, if they are bad.  I'll save those for another e-mail.  Suffice to say the bearings are cheap compared to buying a rebuilt torque tube.

You have two problems.  First, the labor costs.  I haven't done this task myself, to know if there's a better way, but imagine getting under the car, disconnecting, moving, and removing just about everything that goes round and round.  Then disconnect and move out of the way many of the things that go up and down.  Then pull out the torque tube.  Many hours, Many dollars.

The second problem is my wife's favorite.  She calls it "cancer", I call it the Prudent Mechanic's Rule:  While you're there, and everything's exposed anyway, let's check and replace the______________ (fill in the blank).  Very prudent.  Many more hours.  Many more dollars.  And just imagine, with the 944's underside completely exposed, just how many things will NOT fall under this rule?

Drew, after all this, I don't have THE answers you are looking for.  I have more questions than answers, obviously.  If it were me I'd get a second opinion.

Let's do this.  Give the issue some thought, and if you'd like, write back to me using the follow-up feature of All-experts, and let's see where we go from here.  Next time go ahead and give me some more context, especially information like what exactly did you expect from this car...a perfectly preserved 1990?...or a car that's basically sat around for 14 years dieing to be driven FAST.  In the meantime it's melting away from disuse?

And what did you want to do with it.  Not spend a dime and keep it preserved for posterity,...or a complete ground up restoration  'cause it's the cleanest, straightest one you've ever seen?

Looking forward to your next contact.

Dave