Dr_Strangelove

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

michaelo

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.

michaelo

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.

Porschetech3

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.

michaelo

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.

Porschetech3

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?

michaelo

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?

Charles Navarro

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.

michaelo

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

Charles Navarro

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

Porschetech3

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.

michaelo

Good suggestion.

RngTrtl

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.

michaelo

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.

Porschetech3

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?