Tranny Done Blowd Up

When I bought my 348, the tranny was "broken", with a couple of teeth chipped on the drop gear, thus junk in the lube. Fortunately, the trash did not spread, so the other gears were all untouched. Upon disassembly, I found what I believe to be the root cause. The bearings supporting the lay and main shafts on the drivers' side were BALL bearings, and had failed. Perhaps this could have been checked by putting the car in the air and running the trans through the gears (engine running) while listening with a screwdriver to your ear and against the tranny? I don't know for sure.

 

YES!!!!!!!!!

That sounds like EXACTLY like what happend to mine.

It is just about ready to come out. I took off the bumper yesterday, and today I removed the exhaust and the stabalizer bar. Let met tell you, the dual can muffler is HEAVY!!! I bet it weighs at least 65/lbs, easy.

The other thing I found out was why I was having suck a pain in the ass time getting my car to pass smog last year. I bet you can already guess what it was. Yup one of my cats was hollow. But I did get some fun out of it. Since I had the exhaust off, I decided that I wanted to hear that Ferrari music LOUD and CLEAR. Heheheheheee. So I fired it up. YEAH BABY!!!!!! Formula 1 in my garage, on jack stands. LOL!

 

yee hawww !

 

I was close.

I was currious as how heavy they actually are. So I weighed the mufflers and they were 61/lbs!!!! Freekin-A that is a heavy system.

 

Bruce,

Why do you think this? I have a hard time deciding iif a bearing is gone unless it has blown up. Someitmes they feel right in your hand but are just out of spec to make noise when under working load. Thus if I carck the case I replace the bearings. If you take them out of a race and measure sometimes you destory the bearing so a moot point. The lay and main are supported by two huge outer case bearing and two smaller bearing of the same diameter in the webing of the case. These are not likely to fail since they are well supported or foul with other metal from another failure. What makes you suspect this is the source of failure? Also the drop gears are on the clutch shaft and transfer to the pinion drive gear (bevel gear) then to the main and lay. IMO the problem is the stake ring not being properly torqued and locktited allowing movement of the drop gear on the clutch shaft thus destroying the companion gear. This was first reported to me on 4 348C's that were raced. In my case the stake ring was not even staked! I complained to Ferrari and they did not even have the courtesy of answering me. They are big and powerful and I'm just a fat POS. In Ernie's case he reports bevel gear damage just like Byron's 348C had. IMO this damage is probably from improper shimming of the bevel gear or wear in the bevel gear shim that allows the bevel gear to move and thus crack itself or its companion. IMO regular maintenance during a major service would be to open the inspection plate and use prusian blue to ensure gear mating is still proper and that the factory tolerances are still there. If not the problem is a simple fix through the bell house access plate with clutch pumpkin off. Once here you remove the stake ring and place proper spacer and you are back in spec.. It will be interesting to see when I get Ernies G-box if the bevel gear is out of spec in its fore aft position. This issue is much like the preload from crush washers we use on Chevy diferentials. Get it wrong and you get short diff life. Get it right they last forever. I guess I did o.k. I have raced my G-box for 5 years so far.

 

Okay dangit, this car is starting to irritate me. I have EVERYTHING disconnected and the trany doesn't wanna come off of the back of the block. I though for sure I would have it out today.

I removed the 8 bolts holding it to the engine. 4 on the top and 4 on the bottom. The only thing holding it in place right now is the bolt that attaches the tranny to the subframe. Everything else is disconnected, everything. I even when as far as to remove the oil line feeding the sump, coming from the oil tank, just to get it out of the way.

Should I remove the clutch housing and flywheel?

For right now I'm gonna stop cause I'm getting frustrated. It's just better to stop before I make a mistake by working when I'm irritated. That and the winds have kicked up again today. I HATE the winds. They make a mess of everything, and blow dust all over the place. So I think its time for lunch.

 

Magnaflux(ing) is typically done to engines, but, you could do it to any metal component. I will show areas of stress/cracks....etc that you just cant see with the human eye. (ie. before you do a major rebuild into a housing that could potentially be damaged before you start again).

 

How do I write that up for the 348 Repair Tips guide so that we don't all overlook this problem?

Perhaps you and Ernie could take a couple of pictures during his gbox restoration that would illustrate your above comments and suggestions??

 

So we do have a tranny filter in our 348's after all??

 

348 transmission filter, Tav 28, item 32, part #115538, according to the parts book.

I'm looking forward to reading about the repairs and seeing the pictures, but I'm sorry about your breakdowns.

 

FBB, this is a common failure in a 355 and another mechanic I worked with and I believe we found out why.

With a new drop gear and shaft the fit on the splines is tight enough that a great deal of pressure is required to fully seat the gear against the shoulder. We found evidence that at least occasionally the guys in the gear box department were getting lazy and not fully pressing on the gear and instead were relying on the nut to fully seat it. Wrong, the nut will come to torque slightly before the gear is fully down so there is no clamping pressure. Only the size and strength of the splines keep them running as long as many of them do. Once the splines start getting a little worn and the gear starts working back and forth the nut often follows. If proper attention is paid at clutch replacement time it is often found before very serious damage is done, but even just replacing the input shaft and gear alone is $$$$$. Have seen this scenario many times.

 

How do we pay proper attention to the gear being seated fully against the shoulder (at clutch change or flywheel grease packing time)?

Maybe we need our own "Service Bulletin" section on the 348 Repair/Maintenance Tips home page...

 

Ahhhh. Lunch was just what the doctor order'd.

After my break I took off the clutch and flywheel. There is a shaft that runs through the tranny and attaches to the back of the engine. I pulled the shaft out and that made it easier to wiggle the transmission loose. That and with the flywheel and clutch off it made it lighter. Once I saw a little gap between the transmission and engine block I wedged the tranny off little by little. I had a floor jack under it, and once it was off I lower'd it and rolled it out. Then I put it on a dolly to sit for the weekend. I didn't think it would be a good idea to leave it balanced on the floorjack. It wasn't too heavy, but it wasn't light either. I'm gonna guess, without the flywheel and clutch, it weighs about 150 pounds.

Well next stop will be at fatboys place. But that will have to be next week cause I will be busy this weekend.

 

At clutch replacement time if you really understand what you are looking for you can feel it through the shaft.

 

Before you reassemble the gear box with new parts, I'd magaflux each and every component, and look at the gear teeth with a magnifying glass. Any gears with cracks on the teeth should either be refinished or replaced. The gears are good metal, with a hard face on them. Once that hard face starts to go, the gear is going to fail. The surface can get injured because of the loose metal in the oil.

Art

 

Right...except, I don't know what to look for...or even what to tell a mechanic to examine.

I need visual aids! I suspect that there are more 348 owners like me, unaware that a serious ($8,500) tranny problem could specifically be detected/prevented with some sort of proper inspection/re-seating, too...

 

Good advice (you sound like my A&P for my Mooney).

http://www.magnaflux.com/magnaglo.stm

 

If you have a good mechanic he will know what to examine.

You should be paying him for what he knows, not what he does.

 

Aye...I can't disagree with that...though in our non-ideal world I've found that being specific, say, with a list...better, a list that has pictures...tends to garner better results than merely telling a worker "you know what to look for."

 

JJ,

Maybe I can rebuild your G-box and you can fab me a cops conversion? You pay for your parts and I'll pay for my cops parts? I had one FEDex by the heavy weight divsion. I haev no idea what that costs to ship.

 

Excellent tip Rifledriver! I had not considered this nor did I notice any problem when I seat the drop gear to clutch shaft the few times I have done it. In my personal case my stake ring was never staked! It was just torqued and maybe loctited and later backed out. Anyway, I'll pay extra attention to fully seating the drop gear. Thanks for the tip.

 

Gee...I don't really know how you can do that. The shaft is single shear mounted on a large bearing with very little effective play (double shear to the flywheel). Also the clutch shaft drop gear would help to stabilize the play since the bearing can only move fore and aft on the splined shaft that cannot move fore and aft. Thus the only way I can see inspecting for this is perhaps if I could see a mismatch in the clutch shaft gear vs the drop gear on the bevel gear shaft via the inspection hole. I can't remember if that can be done. To do it only by hand on the clutch shaft you would have to have a good feel and experience for a number of cars with this exact failure. I'll check this area out more completely next week on Ernie's G-box before I take it apart. We will try to take some pictures for yawl. So IMO the only reliable way to check this is to remove the clutch shaft which is pretty easy with torch and slidehammer. However, I do not think this should ever be a problem once visually inspected or if the car makes it into the higher mileage like 20K and up. If it hasn't happened by then it may be O.K. unless Rifledriver (a real mechanic) is seeing this failure on 348/355's at various mileages with no particular pattern.

 

Mate, when you order yours order one for me too, for $3000, make it two!