Staffan

My gearbox started to produce a "whining" sound last season at load on all gears.
There where no sound when the gearbox was cold.
Had couple of gearbox experts listening, the cool thing was that they could tell from the sound what the problem was.

I drove with this sound for a few hours on the track, changing oil after each track event just to make sure there wasn't any metal on the plug. Not saying I recommend doing this, but I was told not to worry too much and fix it over winter.

The gearbox is still in pieces so the jury is still out, but it looks like we found the problem. The picture shows one of the two rear bearings on the pinion, as you can tell it's totally gone. The theory is that when the oil got hot the bearing got out of specs making the pinion not aligning well to the ring thus creating the sound.

The interesting part is that after years of track driving the ring and pinion looks good, and so does everything else including syncro rings. So I decided to only change the two rear pinion bearings and hope for the best.

My advice is to really shop around for bearings, prices for the exact same bearing ranges between $50 and $500 usd.

Metal Guru

Staffan, that's good info. Thanks for sharing in the "Turbo 964 for Sale" forum
My big block Corvette had a similar issue which turned out also to be a bad pinion bearing.
Are you doing the work yourself?

Staffan

No I let the pros do this, I hardly seen the inside of a gearbox.
They say the hard part is to adjust so that pinion and ring align correctly.
More difficult compared to other cars unless you have a ton of special and expensive tools, which they don't. So they are going to do this "old school" with marker paint.

Part from that it seems to be pretty "standard".
I think they only spend a couple of hours or so taking it apart.

But the hard part is of course putting everything back and don't have too many bits and pieces left when you close the case

kleinbbc2

Staffan are you rebuilding your LSD. I have rebuilt mine every 30k and have done the bearing change. I'm just glad the gearbox is holding up.

Staffan

No, but perhaps I should while I'm in there.
My long term plan is to get a 996 diff, but I don't have the money now.

How do you decide when to rebuild your LSD, since you do it so often?

Also, when you rebuild do you "only" change the discs, or is it more to it?
Heard it's hard to get the right "tension" (not the right word) in the diff.

Metal Guru

The P.O. of my car had the LSD rebuilt. Apparently it was really noisy, which was the symptom.
Anyway, he went on to say that the Turbo 3.6 discs are the only ones available now. Since they are thicker than the 3.3 discs, they require a 3.6 carrier, which makes the job a lot more expensive.
Jerry, if your reading this, the cost to rebuild the LSD is approximately $4500

kleinbbc2

At 30k I had the bearings fail like you. When the LSD was out placed it on a vise and checked the torque.
60k pulled the LSD and bearings were going but not as bad the first time but the LSD was worn again.
I guess if they are no longer making the disk would buy a guard next time around.

PorscheII

That bearing is actually available in different "grades", which may account for the price difference. There's the standard bearing as pictured, the same bearing but with plastic cage (cheap), and the HD Motorsports version which is very expensive.

Staffan

What I believe you refer to is the ECM and ECP (I think) version, those comes in different version and the latter one has a plastic cage. I refer to what Pelicanpart claim to be the same part, just two different sources, SKF and Porsche.

Check out this link:
http://www.pelicanparts.com/cgi-bin/...20%20%20%20%20

On the lower left side you will find the link for the Genuine Porsche branded version available for another $400 usd. The manufacturers for the different bearings in our gearboxes is SKF and *** (!), I know you can order the SKF bearings from a reseller, probably the same goes with *** bearings.

jeff91C2T

I dropped my trans off to have some work done, to include new plates for the (stock) LSD. Other work performed were new syncro's and 2-5 gears from an /03 trans. A few other odd's and ends done while apart and the out the door price was $3k (which inluded a new pp and clutch disk). Labor was ~$1k of this price as I recall.

PorscheII

That Pelican link is to the roller bearing alongside the ball bearing that you have pictured.

The ball bearing pictured is 999.052.164.00, which is available with brass cage for $150-200, or plastic cage for under $100 (lower grade sold by some major parts distributors).

This thrust bearing arrangement is pitifully underdesigned. Failure of this bearing in a sequential quite often will toast half the transmission, due to resulting misalignment of the shafts. When this became apparent in '03, Porsche Motorsports came up with a HD version, 999.052.227.00 ... same poor design, but perhaps a bit more durable. This is the version costing $400+.

Staffan

Thanks, very interesting information
Just to verify, the 999.052.227.00 is a replacement for 999.052.164.00, correct?

I'm changing both bearings, so you are right the one in the picture is not the one I bought for $67 usd manufactured by SKF. The one in the picture was $224 usd at Pelican (manufactured by ***).

Thanks again, great stuff!
Do you know a good way of aligning the pinion and ring without the use of the mega expensive Porsche tools?

Staffan

Thanks Jeff!
No problems sourcing the LSD plates?

PorscheII

Yes, the 227 replaces the 164 for Motorsports (racing) use ... but I can't say for certain that it's that much better.

I suspect you purchased the plastic caged bearing at that price, which could require a shim change. The original type brass caged bearing probably would have measured out the same as your original.

The standard set-up tools are the only way to re-check pinion depth with the enclosed type diff housing with complete accuracy.

jeff91C2T

Hi Staffan...no problem on the plates. I believe Leif used Sunset in Oregon. The guy who did my work is below;

Woodinville, WA 98072
Leif Johnson
425-788-3476
autowerksnw@msn.com

BTW...the gear change to 2-5 /03 ratio's was a nice improvement. If you can find those used for a good price (I found mine for $400 out of a low mileage regear trans) it's certainly worth considering.