Tod

Just learned that after 65k my "bullet proof" 993 tranny is gone. "Never seen before" bearing failure inside the differential. The bearing cage came apart and the bearings ran around the inside of the tranny until it jammed up the shifter, never a sound, never a performance change just finally it would not shift into the lower part of the tree.

Close to $5,000 for the rebuild. How much would a new transmission cost? Everyone told me the 993 was bullet proof and now I see that this is not so.

This is part vent - part discussion:

Do we have a design flaw?

Only explanation I've heard is that if the car was driven with the spare tire it might have caused the differential to fail. Now, would Porsche design a car where if you have a flat tire you need to rebuild the transmission?

Anyone have a tranny for sale?

Seriously, if the differential is so stressed when a spare is used - why was this designed this way?

Martin S.

Eric Cyranski aka Eric from Chicago has a transmission for sale, or did have a transmission for sale. Eric is a very reputable guy...you won't have to worry about sending money to him.

Just check the postings over the past week on the 993 List, you'll find Eric. Or, Create a Where are you Eric? Post. He'll pop up!

By the way, you can rebuild your tranny with trick close ratio gears, steel synchros, heavy duty shifter fork for about $8,000...see Mark Hergesheimer at Hergesheimer Motorsports, Lake Forest, CA

Eric in Chicago

Martin, thanks for the kind words!
Tod, I am very sorry to hear about your trans <img src="graemlins/crying.gif" border="0" alt="[crying]" /> I just sold my trans (this weekend) to Powerhouse II. After trying to sell the damm thing for 6 months I sold it very cheap.
Give Roger @PHII a call. I sold it for 1600.00 and it was in great condition with 30K miles. If Roger did not rip it apart yet, you may be able to buy it with a slight mark up as is. Roger can be contacted at 641 469 3063. Tell him that I sent you and you have an idea what he paid. Used trans for our car go for 2000.00 to 2900.00. Depending if you have funds aval, the G50/21 upgrade to a stock trans should run about 4-5K. Maybe ask Roger if he would take your bad trans in for trade??? Good Luck

os993

[quote]Originally posted by Tod:
[QB]...bearing failure inside the differential. The bearing cage came apart and the bearings ran around the inside of the tranny until it jammed up the shifter, never a sound, never a performance change just finally it would not shift into the lower part of the tree. QB]<hr></blockquote>

First, my complete sympathy to your situation..but
bearings inside differential? What bearings...as I understand our OEM differentials are nothing more the a stack of discs that "slip" when the differential is engaged...and isn't the differential isolated from the tranny fluid/gear section of tranny, ie I don't think there's fluid within the differential, so how could bearings get inside the gear box?

I've heard the shift fork could break...this wasn't the problem?

Lastly, this is the first time I've heard of such a total 993 tranny failure. For the most part, these trannies are much better than almost all other trannies out there...

Tom W

My transmission failed earlier this year. Once torn apart it was dicovered that a few metal chips had broken off one of the shafts (I think it is called a spider shaft). The differential could not be moved by hand probably because it had a chip wedged in it somewhere. The car ran great up until one of the chips made its way to the bottom of the transmission and obsructed the linkage. This prevented me from shifting into 2nd, 4th or 6th.

This was my start down the steep, slippery slope. I had the transmission regeared to close to the /21 ratios, added a limited slip and replaced the flywheel/clutch with the lightweight RS version. I'm happy with the end result as it definetly makes for a quicker car. I had some problems with stalling due to the LWF until I adjusted the ISV which completely eliminated the problem.

The only downside is that if you autocross the changes bump you into Np class ...and your not really competative in the class until you slide farther down the slope and re-do the suspension, and rechip the car and ...

Tod

Looks like there is a pattern that might be worth investigation.

So far I've found 4 cases of this specific problem happening. Here is the situation as I understand it:

While building US cars Porsche for some reason put Euro spec parts into the differential (so far 95 Cab only). It appears that these Euro spec parts fail (specifically bearing cage inside differential) after reasonably low mileage of street usage. It is unlikely that this was designed this way or intended to be a weak point and must be an unrealized conflict on US cars with Euro parts.

We assume as this point that Porsche knew what is was doing changing out the parts in the manufacturing process but we also know the documentation never got updated. The result being that the mechanics doing the rebuild must search over several years of parts books to find all the parts to replace the Euro parts in these cars.

My mechanic tells that three have shown up in Silicon Valley area, one at CT Automotive, one at the dealer and mine. Also I've heard from the same situation in Toronto area.

Anyone have the same sitation or friends who have seen this? If we get enough similar cases maybe we can ask Porsche what the deal is.

laurence '97 C4S

Tod-
If I read your last post correctly, you are saying that based upon your research (so far) the problem you describe is limited to the '95 model year?

PeanutinCA

Tod,
purely a question, not a poke with a stick. Do you really envisage that Porsche are going to come to the party on a 7 year (about to turn 8 year) old car? I'm Porsche, I ask you, how did you drive the car over those 7 years? Were you a gear grinder, a drag stripper, a racer? Did you perform all services, take every precaution? I know it's a "parts" failure but, 4 or so cases is still limited. The wiring harness issue could have destroyed cars and at a minimum endangered lives, don't see them stepping up for that one? <img src="graemlins/crying.gif" border="0" alt="[crying]" />

Good Luck on the crusade.

Cheers,
Dylan.

Tom W

I can't address the Euro spec of my transmission, but I can add that the guy that did the rebuild was surprised to find that my main shaft had both 1st and 2nd gears fixed on the shaft (like the '96+ model years). I ended up costing me more to reagear because I needed the shaft with only 1st. My car is a late build (July '95). It had about 25k miles on it when the transmission failed.

Greg Fishman

I think almost all 968's suffered from premature Ring and Pinion failures and Porsche didn't help out. this was about a $2500 repair. I wouldn't hold my breath on this but if you don't ask...

Eric in Chicago

All us spec trannys have 1st and 2nd gear fixed to the shaft. Euro G50/21's have a free 2nd gear not fixed to the shaft. I have a real G50/21-2 and the 2nd gear is replaceable without impacting 1st...

Greg Fishman

That is why you will see (or at least I have) 993's with only 3-6 gears changed out. And usually 5th is moved to six so they only needed to buy 3 gears.

Paul

There is a design flaw in the open diff. The two spider gears are installed on a crosshaft and rotate on a set of loose needles. Eventually, the crosshaft wears in the area of the needles. The spider gears then **** ever so slightly, pinching and cracking the spacer which separates the two sets of needles.

When the spacer cracks, the loose needles spill out and go everywhere in the R&P area, and then onward to the main gear cluster. The first clue is usually a needle getting caught in the shift rail bore, causing difficulty in engaging 2nd gear. (not to be confused with a bad 2nd gear synchro)

There is a straightforward fix that we recommend any time the 993 transmission is out for any reason. I would be happy to mail a flyer to anyone who would care to see this simple fix.

Paul Guard
Guard Transmission