996 Transmission Pinion Bearing Issue

Hello Everybody, I am chasing my tail trying to get to the bottom of this issue. I brought to my mechanic my 2001 Carrera 4 to get the IMS bearing done, RMS as well as a new clutch (6 speed manual). When I went to pick up the car it had an awful scratching sound in the transmission when in gear (but not while its in neutral). He is saying now that the Transmission Pinion Bearing is the issue and that it is just bad luck on my part. He also said that nothing he did would have caused this. Question: Is he correct in saying that doing the IMS./RMS/Clutch would not have damaged the transmission at all? I do not know enough about these cars to make a conclusion which is why I am reaching out to you guys.I can't drive it until this is fixed but who is supposed to pay for this? Me or the shop?

Done correctly, nothing about a clutch, RMS, IMS job would cause a transmission issue. All of the work is done on the engine side of the assembly. I can't imagine how it could possibly impact the pinion bearing.

Quotes source post: 15054824

I've never heard a car making a scratching sound before, do you have a video? Pinion failing is usually worse in 3rd gear and happens gradually, getting worse over time. Not suddenly after work

Perhaps it could be something else? Maybe a pilot bearing or a broken spring?

Did they drain the transmission fluid and forget to put it back in? Is it a reputable shop? Meaning...is it possible they put YOUR transmission back in?

Sadly, these gearboxes indeed are susceptible to pinion bearing failures. This thread shows a good picture of the failed sealed 6204 single row bearing, same as the IMS bearing in the 00-05 model year vehicles: https://rennlist.com/forums/996-foru...ring-race.html Was the flywheel replaced? Was the fluid changed in the gearbox? There is a pilot bearing in it as well and the flywheels in my experience most always are bad and need to be replaced. However I cannot see this being IMS bearing related - just want to clear the air on that since everyone always jumps to the IMS bearing as being the culprit.

Car wasn't making a scratching sound when it went it, but was when you got it back ... Hmmm ... Did they (as I'd expect a reputable Porsche indy to do) do a road test before starting work and after completion?

This noise you hear when in gear but not in neutral, is the car sitting still? The reason I ask is if the car is sitting still and in gear, there is nothing moving INSIDE the transmission, therefore could not be a pinion bearing noise.. IF this noise is happening at a certain speed or gear, that changes everything. A very detailed description of symptoms is needed here.

The noise only happens while the car is in gear and moving. It makes a consistent shhhh ...shhhh sound while in any gear at any speed. However, if I put it in neutral while I am moving....the sound goes away. If I am not moving there is no noise, whether or not it is in gear. Overall, the clutch feels great and the car drives fine.....but the noise is annoying. If the windows are open and the radio or a/c is on...it is not that easy to hear. I suspect when they road tested my car, they did not hear it due to these possible reasons. So my next question is this. Is the shop on the hook for this repair or not? It did happen while they were working on the car, and they had to pull the transmission down. Coincidence? They said it was 'bad luck'. But is it my bad luck or their bad luck. Who pays for this? Now if they were fixing something unrelated like the passenger door window, I would agree that it was my bad luck. I asked the shop what they can do for me, and they simply said that they could rebuild the transmission and it will be very expensive. Ouch! Thoughts?

It seems to me you are looking for a internet crowd to support you in blaming a shop for some malady that we can�t possibly diagnose remotely, given the information you�ve shared. Personally, I don�t see how their work (as you�ve described it), could result in the pinion bearing issues you�ve identified. Without better information, this is between you and your mechanic.

I think its possible to aggrivate the front bearing by pulling and reinstalling, if is was going bad. Even with alignment pins the trans will never go back i exactly the same place. Normally a good bearing wouldnt care but if it was failing it could push it over the edge. I do a ton of gear swaps on jeeps. Sometimes an axle seal leaks or a wheel bearing goes bad shortly after. Its just the way it goes when things r pulled apart and put back together.

Quotes source post: 15056434

cds72911, I am way to old to need an "internet crowd" to support blaming a shop. If i wanted to blame the shop I would have simply called Chase and disputed the credit card charge. Rather, I am trying to educate myself to try and understand the reason why this noise suddenly started right after the work was completed in the transmission area. My mechanic said it was "bad luck" (and he may well be correct), but I was hoping for a bit more clarity, hence this thread. I am also thinking that maybe the transmission is not even the issue, maybe it's the new IMS bearing (or something else outside of the transmission). The scrapping noise is only there while driving in gear (no noise while coasting in neutral and no noise while in park) . Question: What are the moving parts between the engine and transmission while in gear and the car is moving? Also, I am also going to take it to another shop for a second opinion today and I will report back their findings here. Basically, I am trying to avoid spending $4K unnecessarily for a new transmission.

Quotes source post: 15057927

If the sound goes away in neutral when coasting or in park, it's not the IMS bearing. The IMS bearing is in constant operation regardless of whether or not the transmission is engaged.

A second opinion is wise but i think the trans has to be pulled to really diagnose the problem.

What clutch parts were replaced when they did this job? Pilot bearing, DMF, clutch plate, spring pressure plate, throw out bearing, new upgraded release lever, etc.? Are the half-shafts bolted up evenly? Can you grab them and see if there is any play? I know you said in neutral, moving or not moving, you do not get the noise. Just trying to get some other ideas out there.

michaelo, I thought you already figured out with your mechanic that this is a differential noise. What changed? https://rennlist.com/forums/996-foru...l#post15027934

Quotes source post: 15058000

Update: I had dropped my car off at an independent transmission shop to diagnose the scratching noise that I was hearing from the transmission (I did not tell them about the new clutch or new IMS bearing). So I went to pick up my car an hour ago and the shop tells me that it's definitely not the transmission, rather it's the IMS bearing (or something right in that area). I then asked him why I don't hear the noise while in neutral and he said the noise is there but it's hard to hear, but you will hear it more while its in gear. He said that is the culprit in his opinion. Well this was certainly a surprising revelation on many levels. A few possibilities to consider: 1. Maybe he is wrong 2. Perhaps he doesn't want to bother fixing a Porsche and just wants me to go away 3. Maybe its a combination of both the IMS and the transmission and both mechanics are right 4. Maybe he is right and it's the IMS So I went back to the original shop who did the clutch and IMS and told them my findings and had both shops talk the phone. After the phone call they agreed to redo the IMS under warranty to ease my curiosity. If it works, great. If not, I will have to put in a new transmission. However, they did say they have never heard of this and this is a very odd occurrence. On the other hand, they also said that they never heard this noise before either. I will keep you posted.

Quotes source posts: 15058000, 15058610, 15027934

I had them rebuild the differential and it didn't fix the noise. In all fairness, they had my car on the lift and with the stethoscope they had me listen in and sure enough it really appeared to be coming from the differential more than any other area. So I gave them the OK to rebuild it. But it did not fix it. Damn noise was still there.

Sounds like you had several low level bearing type noises in your car previously, that you had subconsciously "tuned out" , but then after doing extensive preventative maintenance procedures, had an increased awareness of these noises.. I can't really blame the shop for not reporting these if in fact they had even noticed them. They would to have had to "sell" you on diagnosis of a problem that you haven't even noticed. But of course if it had been to a level of safety, or to a level of causing collateral damage, they would have had a duty to report the issue to you and let you decide on your course of action. Low level noises are commonly masked by high level noises, and the "squeakyist wheel gets the grease first"..I have seen many low level bearing noises masked by "cupped tires" making high level noise, once the tires are replaced and road noise quitened, then you can hear the low level noises.. I think you're just in the process of restoring a nearly 20 year old car, and are not enjoying it.

Quotes source post: 15058777

This is not my first rodeo with old cars, but this one for sure is testing my limits. But once it's all said and done, I am hoping to have a fully sorted car that I can enjoy for many years.

Quotes source post: 15058968

I have no doubt on any of this, but my gut(and some statements from the transmission shop) tells me the IMSB will prove to be fine, and that the pinion bearing is making some noise. How much did they quote you for transmission replacement/repair?

Quotes source post: 15059293

The transmission shop would not give me a quote because they said there is nothing wrong with the transmission, hence nothing to fix there. Question: what test can be done to verify that the pinion bearing is making some noise?

Was this a Porsche specific transmission shop or AAMCO (or similar)? Best to have a specialist give a second opinion experienced in this generation Porsche.

Quotes source post: 15060440

This was an independent shop that only does transmissions. They don't specialize in any particular make or model.

Quotes source post: 15060458

Yup, we have those around us as well. They work on everything and specialize in nothing. Find a Porsche shop to look at it.

Quotes source post: 15060431

Unfortunately there is no specific test to verify a noisey pinion bearing, It's buried deep within the trans. Like Charles indicated , experience with these particular transmissions is the best equipment/test for this diagnosis, but a quality set of " Electronic Bluetooth Chassis Ears" can give some insight.

Quotes source post: 15060793

Good suggestion.

Quotes source post: 15061325

The best suggestion. These arent f150s that every shop has worked on. You need to find someone who specializes in german cars, hopefully specializes in Porsches. Doing anything else results with the exact dilemma you are in now.

Quotes source post: 15062206

The original shop that put in the IMS/RMS & clutch is a German car Porsche specialist and here we are today with this thread. But they are working with me to try to resolve this and i am hoping for the best.

Quotes source post: 15063145

And this is the shop that that found the noise in the front differential, and then diagnosed the pinion bearing noise? they haven't given you a quote on the pinion bearing?

If it were me the trans would already be out and on the floor. The suspence of not knowing would be killing me. a quick question though, if u pull the trans cant u run the motor to see if the noise is there. If not i would say the ims is fine and its in the clutch or trans.

Any update on this?

It could be the flywheel centre bearing , could have been damaged when putting the trans in as the drive shaft from the trans has a little centring shaft on the end which is a tight fit going back in and the trans has to be perfectly lined up and the clutch plate perfectly in place, just another option for you. If the noise wasn't there before and it is now, your mechanic should pull the trans off to check his work, I would do that as a courtesy !!

Here is where I am today. I could pay to have the shop take down the transmission and send it out for a re-build. However, if it comes back with an issue- neither the shop, nor the re-builder will take responsibility. They will simply blame each other for poor work and I will be stuck with the problem again and out of money. On the other hand if I take it to a shop that will do both (drop the transmission and do the rebuild) - the warranty they offer is just not good enough for what they are charging. It will probably fail the day after the warranty expires (doesn't it always) and I will be out of money again. Bottom line is either option is very expensive and not worth pursuing because the car does not have enough value. In addition, I have yet to see a transmission ever get repaired right. Lesson learned: I should have just enjoyed the car as it was and left the IMS alone. "If it ain't broken, don't fix it" I won't be making that mistake again.

Why would you send the trans out for rebuild when you don't even know if its the trans that has the issue? Maybe I missed something and need to go back and read again? Has the throwout bearing ever been replaced (noise change when clutch pressed)? Dropping the trans is not a difficult job and can be done by you, saving a bunch of money!

^^ Agree, dropping the transmission isn't that hard. So why won't your indy shop should be willing to pull it for you and check? I agree with Noz... It's a lot easier for them to do it on a lift with lots of experience than it is for you to do it in a garage, seriously like an hour of real labor for an experienced tech. Once the transmission is off rechecking the throwout bearing and lever is easy. If you have to pull the pressure plate for some reason even that isn't hard and only costs a few bucks for new screws. When I did my IMS I did the pilot, arm etc... all the parts in the transmission bell along with the clutch/flywheel/RMS/Master Clutch/Slave Clutch, so everything was great when I was done. Also used LN bearing, thanks Charles. I regret not knowing about the free tool rental, or I wouldn't have bought through Pelican. I made my own tool. For what it's worth, fixing these G60 transmissions can get expensive thanks to the parts (or so some of the Porsche specialty transmission guys have told me, like GBox). When mine started popping out of second gear I called around checking prices and options. Eventually, I decided to take a chance on a low mile transmission from a trusted source. It cost less than repairing mine. I plan to learn how to do the repair myself (hopefully) so I've kept the original transmission for a future project. I feel for you, I did my IMS bearing because I was replacing the transmission anyway, would have sucked if I did the IMS then had to swap the transmission.