Originally Posted by JMLavoie

Adker:
How much would a job like this, cost you approximately, if you are so inclined to mention it?
My #2 and #4 synchro rings are not notchy and although not in a rush, I need to start planning to do something about it. Thanks!
Martin

Originally Posted by 450knotOffice

My 996 has 137,000 miles on it, mostly on the freeway (although it has had a few track and autocross days thrown in for good measure). About 35,000 miles ago, I began to notice a faint whine - similar to the sound that straight cut gears in racing transmissions make - emanating from my transmission area. It would present itself mostly while load was applied - either through acceleration, or deceleration - and would quiet down during coasting.

I eventually had my friend/Porsche mechanic take a look at it, and he told me it was either the Pinion bearing, which has a history of drying out and failing with these transmissions, or possibly the Carrier bearings, which can make a similar noise, but are a lot cheaper and a lot easier to replace.

He was about to pull the transmission for a clutch replacement and while in there was going to replace the original IMS with the updated LN Engineering version and also replace the RMS. We figured - while the box was out - why not replace the cheaper Carrier bearings first and see if that solved the problem.

Well, it didn't.

I was up to my eyeballs in expenses at the time and the last thing I could afford was a full transmission teardown to replace the obviously worn Pinion bearing - at least for a while anyway (without putting it on my credit card, which I'm hesitant to do these days because I paid off my cards a few years ago want to keep myself off of that crack pot for good). He mentioned that the transmission would almost certainly NOT self destruct over the short term - it would just get louder and louder. So I put it off.

And I put it off.

For about 30,000 more miles.

Well, it got SO loud that eventually it became deafening at highway speeds. It was awful. I mean, I couldn't even hear the engine over that racket. Interestingly, it never lost its shifting smoothness through all of that. At least until it got so bad that I decided I was playing with fire and decided to park it. The final straw was that I was feeling a weird vibration in the stick in second gear and the lever did not slot in on the upshift to second without a little hesitation and shudder. Uh Oh! Ok. I give up. Time to park this thing.

So, I called my friend and told him it was parked until he rebuilt the transmission (which he gave me an AWESOME labor deal on, btw). A few weeks later, I drove it to the shop he uses for his little side jobs (a place run by another friend of ours) and we immediately tore into it. In no time, the transmission was out.

He sent it to another guy he knows who has the equipment to press the gears and bearing off of and on to the tapered shafts. He called me a week later and told me that they had NEVER seen a bearing as trashed as mine! I was not surprised. Look at the pictures below... The ball bearing cage was coming apart. The ***** themselves were so worn they weren't even round anymore, and the inner races were scored beyond belief. Take a look at how much metal sludge is on the magnet. There was so much bearing material floating around that the carrier bearing he replaced the first time were trashed again, so I had to buy new ones - again. In fact, I decided to buy all new bearings for the transmission and differential. If it was a bearing, I replaced it. In all, I spent about $1350 on bearing alone.

Luckily, the gears and syncros were all unscathed. They were all in nearly perfect as-new condition, thank God. The Spider gears, which apparently have a tendency to become pitted over time, were perfect. No pitting whatsoever

Considering that the Pinion and Input shaft bearings are sealed units similar to the infamous IMS bearing, with the same inherent issue - namely the grease eventually exits the bearing, yet the transmission oil can't seem to get back in very well to lubricate the bearing - my mechanic decided to pull the seal off the new bearings in order to allow the transmission oil to lubricate the bearings, just as it does all of the other internals.

He's in the process of putting it all back together and I should have the car back on the road by the end of the weekend. I'm looking forward to the peace and quiet again.

A few things to be gained by this episode. One, unfortunately, due to the design of the bearings for this transmission, it seems that more and more of these units will begin to exhibit the same bearing failures we all know so well with the IMS issue. Two, DO NOT wait as long as I did to tear into the transmission once you begin to hear that whine or howl. Luckily for me, it seems that this transmission is quite robust - even when doofus me neglects it to the point that I should probably have my Porsche card permanently taken away from me. For an unreal number of miles, it soldiered on as I continued to drive it with a failing bearing. Amazing, really.

Here are some pictures:

Originally Posted by joshb217

I'm having some similar issues and have a question regarding symptoms. I have a whine/howl going on when I'm in gear or nuetral regardless of clutch position or in gear or out of gear. The pitch changes with rpms. It has gotten worse over the last 5-10 k miles. I did remove the belt and the whine/howl was still there. My car is a manuall with 70k miles. Is it likely I could have this pinnion bearing transmission problem while I'm in neutral and not using the clutch at all? What all bearings are in motion when you start the car and do nothing but rev it? The sound seems loudest behind the oil pan area imo. I just changed the oil and not a single sparkle in the filter. My goal for this comment is to either rule out or confirm this could possibly be the problem. I will give any information I can. The shop i visited today wasn't sure and didn't want to jump the gun on it being the trans because the car is very clean underneath and there are 0 shifting issues.

Originally Posted by am

Do you have that noise when the car is not moving or only on the road either the clutch engaged or not?

Originally Posted by AWDGuy

this howl in every gear?

Originally Posted by joshb217

Every gear including out of gear.

Originally Posted by AWDGuy

this howl in every gear?

Originally Posted by am

I think your noise comes from the engine or pilot bearing. Not from transmission.