Gearbox autopsy...UDDATE

Man, that is scary!!! Three bearings in less than 40K miles? I don't know much about 348s, but what is up with this design? Lars, I am really glad that you caught this before............$$$$$ Ernie, FBB, et al., as usual, were right.

 

OMG, I thought this was from your original post problem! I think it's time to call an Exorcist.

 

Sorry. I thought your box broke on 2 separate occasions. BTW, Lars you should really be very proud of yourself and your mechanical abilities. There is probably only a handful of people on FChat that would tackle this problem on their own. I don't know that I would have the bal_s to do this in my garage. You da man!

 

That is not factory ferrari silicone. Don't blame the 348 gearbox. Someone was in that gearbox before you! Who knows what they did or did not do.

 

Lars look at http://www.ferrarichat.com/forum/showthread.php?t=207294&page=2 I enclose pictures of my bearing damage, which is exactly as is in your case, just not as far progressed. While you are there, you may as well check the ringnut in the clutch control diagram, and the plug at the end of the mainshaft which ensures the pressurized gearbox oil makes it up to the differential (which mine did not).


I want to practice some Danish...

Lars, de to lejre på begge sider er sat op som par. De to på oljepump siden er "thrust bearings", og de to på den anded side er "roller bearings". Thrust bearings has både funktionen at holde akslene i linje med hinanden (derfor er det så vigtig at "ring nuts" er stramme, så akslen kan ikke flytte fra side til side, mens roller lejrene har kun et rullende funktion.

Når bilen bevæger sig, saa er der en del drejemoment der prøver at flytte hovedskaften til venstre og "lay" skaften til højre (du kan se hvordan selver gærne er sat op. De to "thrust" lejre holder dem i ligning samt med den normale rulning af skaftet.


Now I give up and go back to English...
You may be able to get them from SKF - I did get them from there for about GBP 68.00 a pair plus VAT.

If the Danish folks at SKF are a pain, try these guys (where I got them) Acorn Industrials (+441709789999), ask for a lady called Lynn. The Original Ferrari bearings were part number BA2B633912 with a C3 designation (hardness and precision) - these have been replaced by BA2B636151A also with C3. The dimensions are : outer race 76mm ø, inner race 35 mm ø and bearing width is 28mm - I don't remember the thrust angle, but I do remember it matches the original (don't know why 43.5 degrees rings a bell). I got them for about DKK 300 each (yes 300... - GBP 34) + VAT and shipping and they got delivered in 3 days.

Marco
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If you have a clunk when you turn the shaft underneath the one going from the engine to the clutch, you also have a loose ringnut on the drop gear. Look at the link I posted just above, I had that too. The solution is either a new SET of drop gears (megabucks / Kroner) or if the splined shaft (see clutch control diagram) is not too damaged, you can clean it, put a bunch of special bearing/axle adhesive (similar to loctite but stronger) on the splines, put some Loctite one the ringnut and tighten the "lort" out of it. Let it set overnight, then reassemble. The clunk is now gone in my car. Incidentally, that is the gearing that Michelotto tunes for the different race profiles, and also the main difference between the 348 gearbox and the Mondial t.

Marco

 

Marco:

You are a true "renaissance man" - Ferrari mechanic, fabrication expert, linguist.... You are really an intelligent man and you certainly impress the hell out of me.

Scott

 

Great thread!

 

I am going to take my gear box apart this winter..........better safe than sound.

Just to check that everything is in order........just to prevent what you have gone through.

Would it be possible for you to give me a hand..........whenever it suits you of course.

Where do you live??? Which town I mean?

//B//

 

When fatbillybob and I put my ring nuts back on, one of us held the the shaft on the other side of the box while the other tightened down the ring nut.

You need to use Loctite 271

In my shop manual it gives a torque rating of 22 daNm.

If I'm remembering correctly I think we put mine back on using couple of blips from an impact wrench? We wanted to make sure that the ring nuts were on there good and TIGHT, if you know what I mean. Then I beat the crap out of the ring nut to make sure it was staked on there GOOD.

The shop manual spec for the oil pump cover is listed at 2 daNm. I put mine back on by feel.

The intermediate cover is the one you want to pay attention to because that is the one holding the bearings. I tightened that one down by hand also. The manual doesn't give the torque specs for the intermediate cover. But what I did find was the specs for the differential flange covers and that is listed at 2.8 daNm. So, I really have no idea what the specs are for the intermediate cover on the oil pump side of the gear box. Like I said I put mine back on by hand.

Try hitting up fatbillybob, he may have the specs for those, because I can't find anything for that one in my book.

Again did it by hand.

The manuals are missing sooooo much information.

As you have probably found out the CV joint bolts are on there TIGHT! I had to use a cheater bar on the end of my long handle ratchet to get them to come loose. So when I put them back on I just tightened them back down as tight as I could by hand.

However,

I ran a search of the archive and found the torque specs for the 328 CV joints and those specs are, 8 Kg-m (57.5 ft-lbs) for the cv bolts.



I hope that helps Lars? Sorry I couldn't give you the rest of the specs, my manual just does not have that info in it. Maybe someone else has that information but I don't. If I had the information you know I would give it to you. Hopefully if someone else has the info they will share it.

 

Okay now,

About that failed bearing. I am assuming that is the one on the oil pump side of the main shaft, that was on the back side of the intermediate cover, right?

Which brings me to my next train of thought.

Fatbillybob was sure it was loose ring nuts, and he was correct. However, I was sure it was bad bearing design. By the looks of it I am also correct. Because it is evident that the bearings will still fail even though the ring nuts are on properly. We now know this thanks to you posting the pictures of your main/lay shaft outer ring nuts being on tight and staked properly. Then when you posted the video of your oil pump bearing ball bearing retainer having play it, that demonstrated what I had been advocating all this time. And that is that, the bearing is not up to handling the lateral loads being imposed on it by the transmission.

Now what we need to do is figure out what bearing design will work best with our application, so that we can prevent this this from continually happening.

 

You should have bought them from Daniel at Ricambi. Right now the €Euro is more valuable than the $Dollar. Just had a look at the exchange rate and as of this pposting $1 would have only cost you €0.68. In other words you would have gotten a 32% discount for buying it from here in the US just because of the exchange rate. Come on bro, if we are going to save ourselves money we have to think about how to save money anywhere we can. Plus Daniel-son is the man. He has outstanding service, and ships internationally.

 

One more thing.

When I put my gearbox back together I used Hondabond HT to seal it up. The stuff works great. I have absolutely NO leaks coming from my gearbox. Not one drop.

Hey did you ever take up Marco on his offer? He said he had a couple of extra bearings sitting around. Never mind, I guess you didn't since you already ordered from Eurospares.

 

Here is the catch...
The exchange rate has been in to “our” favor for a while now. The problem is that if you buy parts from the US, customs will add ~30% in tax and besides from taking forever to get the parts it isn’t that much cheaper any more :-( This is the way it works in Sweden and in most EU countries as well.

 

Well that SUCKS!!!

 

Lars,

The bearing I mention is behind the panel with the 4 bolts you posted in a previous message. It is the hollow shaft through which the engine shaft runs from the engine to the clutch. When you take the clutch bellhousing off, you can't miss it.

The data in the book is OK, on new kit. Just make sure you go 5-10% above and then use FatBillyBob's method of breaking the ring into the shaft recesses/dimples, to ensure the ring nut does not loosen. Also drown the threads in loctite.

Marco