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borsonie

'99 996 tiptronic differential

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I'm a newbie here, but hoping the community has some good advice.

I recently purchased a 99 996 tiptronic coup from an established Porsche dealer outside Washington DC. 89k miles, but looked solid and the price was good. I walked out the door with a 30 day/1000 mile warranty. Literally, right after 1000 miles, I get a transmission issue. I stop immediately and have it taken to a nearby Porsche dealer. They do a cursory inspection and conclude I need a new tranny....$10k. I then have the car taken down the street to a local Porsche specialist in Baltimore, MD. They do a more detailed inspection and feel it may be a reparable differential bearing. They pull the tranny, open the differential and NO OIL! There had been prior evidence of a leak and even when I had the roadside issue, no fluid on the ground. The tech's opinion was that someone had serviced the the tranny and forgot to replace the oil. The dealer confirmed they checked all fluids (performed an "extensive inspection").

So, I called the dealer to try and get to the bottom of the issue...track down when the tranny service was done, who could have made this mistake, etc. ZERO RESPONSE from anyone. They called me like crazy before the purchase, now I can't get a call back. The shop can fit a rebuilt tranny for about $4k. Questions:

1. Could I have totally missed a leak?

2. Would the car have driven okay without oil in the differential (at least for the 1000 miles)

3. I am considering a letter to Porsche Cars North America, has anyone found them responsive?

4. Should I have the local shop repair the car and then pursue resolution with Porsche?

Any other thoughts would be appreciated.

Eric

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:welcome:

Sorry, but could you clarify... the Tiptronic uses Porsche ATF - the differential uses gear oil.

Which was without out oil?

The differential was without oil. Sorry if I was not clear.

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What is the car doing? Symptoms?

There was a hesitation and a slight grab...no grinding, or other unusual noises....felt bad, so I stopped and had it taken to the shop.

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:welcome:

Sorry, but could you clarify... the Tiptronic uses Porsche ATF - the differential uses gear oil.

Which was without out oil?

The differential was without oil. Sorry if I was not clear.

The differential in a Tiptronic car only holds 0.9 liter so they might want to double check that it was empty.

I also doubt that a differential problem would hurt the transmission unless it totally locked up.

I would get another opinion from a known good Porsche shop. That's my 2 cents from what you have told us...

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:welcome:

Sorry, but could you clarify... the Tiptronic uses Porsche ATF - the differential uses gear oil.

Which was without out oil?

The differential was without oil. Sorry if I was not clear.

The differential in a Tiptronic car only holds 0.9 liter so they might want to double check that it was empty.

I also doubt that a differential problem would hurt the transmission unless it totally locked up.

I would get another opinion from a known good Porsche shop. That's my 2 cents from what you have told us...

I got it out of the dealer and to a Porsche specialist. They made the call on the new trans and the empty differential. Differential bearing failed and resulted in a chewed up differential housing. This is what I understand so far...been out of town and have not been able to see the box. The differential is integral with the transmission box, correct? Still learning, so thank you for your input/comments.

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Eric, Sorry to hear your difficulties. I had to replace the seal on my differential last year as it was leaking. It didn't leak much but boy did it make a mess. The oll had gotten everywhere and collected gobs of dirt. I spent FAR more time cleaning the bottom half of my engine compartment than replacing the seal. In short, I can't imagine missing a leak.

FYI, There is no drain plug on the diff. So for regular maintenance/inspection, you just open the filler plug (near the middle of the unit) and check/top off. I forget the servicing interval (90k miles?) for the diff but for that you suck the oil out and replace it.

In my simple mind, there is no, repeat, no way in the world you can miss a diff leak (or any other type of lubricant leak) on these cars. The evidence is all over the bottom of the engine....

I can't say how far a diff will make it without oil but, remember, they probably didn't/couldn't suck it dry. What was left was enough to get you 1000 miles. That is my guess.

If you don't see an oily mess under your car, I'd say the dealer's mechanic sucked the oil out and forgot to replace it.

I'd take lots of pictures and statements from your shop. I'd approach the GM of the dealership. Review your situation. Tell him that you'd like to give him an opportunity to make things right before you a) head to claims court AND B) write to Porsche USA. I'd stress both actions to the GM.

Again, sorry to see your Porsche experience start this way.

Good luck,

GA

  • Upvote 1

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UPDATE.

My car is repaired and the tranny is great. I lucked out and the shop find a gently used tip for about 3800 bucks. Total repair was about 5k after labor, replacing seals, and fluids. I kept all the old part a as evidence. I had been attempting to work with the GM of the Porsche dealership in Rockville, MD. It's like pulling teeth....never returns calls or returns email unless I pester him. I asked for a reimbursement for the cost of the used tranny....I offered to suck up the install. No answer..bugged him...he offered $1000. I indicated I would not let this go and would take it to PCNA and court if necessary. He came back with $2k. I reiterated I simply wanted them to do the right thing and at least pay for the transmission. After all, they failed to properly inspect or fill the differential...and all but admitted it by offering me $2k. They went silent. I sent a letter to CEO of PCNA and my wife (an attorney) has begun to prep to take this to small claims court. I'm not sure what to expect now, but it's kinda sad...I really wanted to have a better first experience.

I have been surprised how little expertise exists in the dealership...they don't repair much of anything...just do component replacement and then charge a fortune. The one good thing oit of this...I found a great shop staffed with craftsmen.

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Sorry to hear of your issues.

Quick related question: I have a 99 Tip also. I requested that my Tip and Differential fluid be changed at the Porsche dealer a couple of years ago. But when I got it back, the dealer told me the differential is sealed and so they only changed the Tip fluid. They said only later 996s had refillable differentials? Can anyone confirm that the 1999 does indeed have a separate diff fill hole? where is the fill hole, my porsche manual doesn't mention it at all.

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Dammad, I saw your original post on this. Did you look at the DIY that Loren pointed you to? Lot of good info there. To answer your specific questions. Yes, your 99 Tip is just like Eric's as well as mine (a 2000). Your differential is separate from the transmission. The differential is on the drivers side of the transmission. If you get under the car. Looking at the transmission from the drivers side. The differential is the housing that is between the transmission and the drivers side rear wheel drive shaft. The differential housing is round, about 12 inches in diameter. If you look at the 9 o'clock area of the face of the housing, you'll see a plug with an allen head cut into it. That is the fill plug for your differential. There is no drain plug. You change the fluid by sucking it out and then refilling it.

I've attached the page from the shop manual that describes the diff fluid change. The picture/drawing in the middle of the page is looking at the transmission from the drivers side of the car from in front of the rear tire.

This is not covered in your owners manual.

GA

Tipronid differential fluid change.pdf

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Eric glad your back on the road, very unfortunate turn of events.I am surprised they offered you 2K.

Gator thanks for the info, going to service both the ATF and differential soon any tips on the fluids 75W-90 synthetic? what brand of ATF fluid. ATF LT 71141 not easy to find, My dealer is quoting $12.00 a liter but comes on a 20 liter container. Izzy posted the use of Pennzoil don't want to chance this on a 10k transmission.

Edited by jayi836

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Hey guys, I changed the diff fluid in my 99 tip. It was really pretty easy. I purchased a suction tool at Autozone and a quart of Royal Purple 75w90. I put her up and pulled the left rear tire off. I think the hex was a 8mm short. Pulled the drain/check bolt and sucked out as much fluid as I could then I pumped fluid untill it was at the same level as before-even with the drain.

I spent a lot of time letting the fluid settle to make sure it was full. easy job.

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Hey guys, I changed the diff fluid in my 99 tip. It was really pretty easy. I purchased a suction tool at Autozone and a quart of Royal Purple 75w90. I put her up and pulled the left rear tire off. I think the hex was a 8mm short. Pulled the drain/check bolt and sucked out as much fluid as I could then I pumped fluid untill it was at the same level as before-even with the drain.

I spent a lot of time letting the fluid settle to make sure it was full. easy job.

I did mine today and it was easy, but while before I had a slow drip, now I have a relatively major leak.  Did  you experience any leaks due to possible overfilling?  I filled mine to .9l when it started coming out of the hole.

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I have had no leaks, so far. where is some wood to knock on....

Is your leak coming from an overflow tube? It has been a while since I posted this so I can not remember if it has an over flow tube.

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Last night I replaced the Rear Diff seal for the output flange.  I would say that changing this was a 'moderate' job.  The seal was about 40 dollars. Time about 2hrs.  Key tools were

 

1) ball head hex wrenches to remove the axle from the diff,

2) 32mm socket to remove the axle bolt (may not be necessary)

3) Air hammer to free the axle shaft after it was separated from the diff (may not have needed this)

4) Impact wrenches (just to speed things up)

5) A seal setting tool

6) New seal W0133-1934070

 

 

Unfortunately I did not take pictures so these steps may not be exact but will get you there.

  1. Remove the drivers rear wheel.
  2. Using the ball head hex wrenches remove the hex bolts holding the axle to the diff (#20 in suspension diagrams)
  3. You will now be able to slide the axle away from the diff.  It is a tight space. We found that moving it to the lower left gave the most space
  4. Now you can see the assembly behind the axle this is held in place by a single allen bolt
  5. Remove the allen bolt.
  6. It is likely you will not be able to pull the plate because the axle is in the way.
  7. Here we had to remove the 2 upper control arm bolts (#10 in control arm diagams).  This allowed us to lower rear assembly without removing it.
  8. Here we used the air hammer to loosen the axle from the rotor assembly but this may not have been necessary it just gave us more play to work with when trying to move the axle out of the way.  The expectation is that this should not affect alignment since capser and camber are on the lowery control arms, but we will see.
  9. With the axle positioned out of the way, remove the plate from the diff
  10. You will see a seal in the diff, you will need to pop this out. It is held in by a tension spring around the inner seal
  11. Place the new seal and using a seal tool or other, put it in place and make sure the inner spring has engaged to seat it.  (it may be worth buying 2 seals incase you pop the spring on the first)
  12. Once in place reverse steps from above
  13. Fill diff fluid
  14. Take her for a spin, park your baby, put some cardboard under her belly and check for leaks.

 

Really the most difficult parts were

  1. Since the wheel assembly was not removed,  the axel could not be removed so finding space to offset it to remove the diff plate
  2. Seating the seal – Just due to being over cautious.

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