348 Main , Layshaft disassemble

Hi,

can anyone explain me how to disassemble the main and layshaft? I removed the 4 ringnuts. The gear selector forks and shafts. And now?

Samy

 

You have to bang it out, unless you have access to a nice big press.

When I took mine apart at fatbillybob's house he had a bunch of metal pieces that we had to hold inside the gearbox to keep the center bearings in place. Then we put a cap on the end of the shaft, with a piece of delrin/plastic inside it, and I banged it out with a sledge hammer.

I dunno if fat boy has any pics of the procedure?

If you have a big press that would work better, but you will still need some way of keeping that center bearing in place so you can bang/press the shaft out of the center race.

 

One more thing I forgot.

If you are looking at the front of the gear box, that's the side that attaches to the back of the engine, it gets pressed/banged out to the left.

Hit up the fat man, or even plugzit, and see what else they have to add.

 

And,

How come you have to remove the main and lay shaft?

 

Thanks for your help. So i have to hammer both shafts to the left / Oilpumpside right?
And how do you hold that bearing inplace didnt the fixed differential gear on the shaft push it out itself anyway?

I have to remove the shafts to get access to the gear wich is driven by the clutch shaft. That one explode somehow and so i got to renew clutch shaft with the gear on it and also the other gear inside the gearbox driven by the clutchshaftgear. The rest looks fine till now, except the small metal bits from he exploded gear everywhere.

 

You hammer on the oil pump side out towards the other end.

As I was saying, fatbillybob had some metal bits that we placed inside the gearbox to hold the bearing in place. We wedged them between the gearbox housing and the bearing race. If you look inside the gearbox you will see some small retainers on either side of the bearings. The retainers are screwed to the gearbox housing via a allen screw. Those retainers are not capable of withstanding the impact of the sledge hammer hitting the shafts. They will bend/break. But they only hold the outer race to the housing, it's the inner bearing race that needs to come off. But, you need to hold them both still. You have to keep the bearings in place so that as you are banging on the shaft it will be getting pushed out of the bearing. The bearing cannot be allowed to move from it's position in the center of the gearbox. The main thing is to keep the center race, that's the part pressed onto the shaft, from moving, you want to hold the race still while you are pressing/banging out the shaft. So what you are going to have to do is figure out how you can wedge some solid pieces of metal, plastic, wood, pipe, or whatever will work to hold the bearing in place.

 

Forgot something.

Before you go trying to get the shaft off the bearing you need to remove the differential. If you haven't removed the differential you'll need to do that first.

 

Here Samy,

Have a look at some of the pictures in this thread http://ferrarichat.com/forum/showthread.php?t=77427 you'll see the retainers I'm talking about on page 5.

 

Thanks the pictures are great. On the pictures i see that they managed to remove the outer bearings without removing the shaft. How do i do that? Do i have to destroy the bearings to get them off?

And the differential do i need to remove the gear ring from it? Because i have it loose but i can't get it out of the gearboxcase because its to big with the layshaft still in it. So i thought i have to remove the layshaft first.

 

Yup.

The roller bearings will fly all over the place.

I'm guessing you are only going to change the ring and pinion gear and not the bearing? I changed out all the bearings when I did mine rebuild.

If you are going to do it that way what you will need to do is, secure the roller bearings in place with Ferrari especial tool #96 (a rubber band). Here is a picture of it here. http://ferrarichat.com/forum/showpost.php?p=135948915&postcount=2 Get the shaft started out, but not all the way. The put "ferrari especial tool" #96 over the bearings. LOL! That way when you take the shaft out all the way they roller bearings don't go everywhere and stay on the inner race.

 

Nope you don't have to remove the ring gear, the differential will come out in one piece.

Hold on let me see if I can if my old post on how I describe getting it out.

 

Found it!

Here is the link to that thread http://ferrarichat.com/forum/showthread.php?t=102751

Now I remember better. Okay here is how the differentials comes out.

Remove both of the hub shafts from the differential. Those are the parts that the inner cv joints get bolted to.
Then remove the cups for the differential bearings on the sides of the gearbox.
Next remove the bearing from the oil pump side of the differential.
Now rotate the differential so that the ring gear is facing out, towards the open/front of the gearbox. You want the oil pump side of the diff to go inside the gearbox (towards the clutch) and the ring gear towards the open face of the tranny.

The diff will come out. You just have to rotate it ever so slightly to get it positioned just right to come out in one piece. Don't get frustrated it does come out in one piece.

 

I think i'm to stupid for it. How do i get the bearing of the diff? And how do i rotate it that much? At the moment the layshaft gears are in the way to rotate the diff much more then maybe 10-20°. Maybe more but never 90° to let the ring gear face the opening of the gearbox.

 

Why with a bearing puller of course.

Once you have the bearing cups off, and the bearings, you'll be able to move the diff just enough to get it out. But you have to have the cups and bearings off to do it.

 

i try to build me such a tool today well maybe it will work then.

I can get the two damaged gears for a good price but they are the old 10 groove spline. Is that spline still available from ferrari or do they only produce the new fine splined one and i will get a problem to buy such a fitting 10 groove spline?

 

The gear box is made by ZF (Zahnradfabrik Friedrichshafen) not Ferrari, and since they are a Deutsch company maybe you'll have some luck with getting a new ring and pinion set directly from them? Soon as you get your pinion gear out have a look at the manufacture number stamped on it and give them a call. I would imagine that the same type ring and pinion set is used in some other automotive application, as I found out the majority of Ferrari's stuff is. So you may be able to get it at a big time discount, that and they seem to be listed as "unobtainium" by Ferrari. So give that a shot and see what happens?

 

I will try that. Without you Ernie i would be lost

Today i found out that my clutch shaft is out of a 355 and was produced 07/2003 the damage occured 09/2005 the ringnut loosen again. They used the old ringnut i see two or even three stakes. But now i'm confused. My broken gear has 26 tooth. And if i look at eurospares there is no 26 tooth gear listed. With the 355 clutch shaft there is only a 25/27 and 25/29 strange. 26/27 is available with 10 groove on the old 348 clutchshaft. I'm confused.... what should i buy to fix my problem. 348 ,355, mondial T ... parts ... i weld my broken gear back together


Here is the broken gear http://img29.imageshack.us/gal.php?g=dscf5024o.jpg

 

On second thought forget about the manufacture number. I dug out my old bevel/pinion gear to have a look at the number, it's just has a hand scribed number, which seems to have been done by whomever put the transmission together. Anyway you can see how my gear was completely gone, and mine is the old 10 spline like yours.
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OOOOOOOOH SNAP!!!

Yeah that thing is broken alright, and I think we are talking about a completely different gear? Is that the transfer gear that is behind the slave cylinder?

 

Sorry about your misfortune but people talk about upgrading their 348 box with 355 small spline shafts. It is obvious that this did not help you. In fact yours is the biggest transfer gear explosion I have ever seen. You will need to rebuilt the entire box.
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Yes that doesn't help if the ringnut comes loose. It maybe makes it worse ! Because the fine spline is more durable so what happens on a fine spline shaft if the ringnut is loose

1. the gear moves
2. the tooth from gear to gear aren't aligned anymore
3. on high engine torque the big tooth of the gear , like on mine, break and the two gears get stuck and one will break in many parts.


on the old 10 groove shaft i think it will happen like that

1. the gear moves
2. the 10 grooves on the shaft can't support the torque and wear fast till they break away complete befor the tooths from the gears break.
3. Less potential danger for the rest of the gearbox from broken parts.



I got my gearbox appart and had luck nothing else get damaged. I only have to change the two transmission torque gears and the clutch shaft with a new ringnut. Can i use any transmission torque kit 25/27 , 26/27 , 25/29 348, 355, mondial T does it all fit inside?

 

YES! but the gears must be paired. Use a new 25/27 for example not a new 25 and an old 27. You know what I mean? The WSM has the available ratios. For a streetcar there is little difference. You can get a bit more gas mileage and lower RPM at speed at one end of the spectrum or an imperceptable amount of extra acceleration with the other extreme.

 

Yes ofcorse all from the same. I will buy a pair because i need both new both are damaged. But all will fit on the bevel thing inside the gearbox shown on ernie's picture? I thought maybe they used a different spline on that too that i first have to look what spline i got in their but if its the same on 348 and 355 gearboxes would make it easier. I thought about buying 70000839 that should be the clutch shaft plus the two gears in 25/27 as a set. I hope.

I'm not looking for gas milage or top speed just acceleration, the engine wouldn't life long on high speed runs so thats a no go.

 

Ok got my transmission completely apart now. It looks like it is in pretty good shape. I found out it was overhault 2004 one year befor i bought it and put it into the garage. So it only has a few miles on it.

But i got a identification problem.
I found out that the clutchshaft and gear on it are from the Ferrari 355. Now i'm wondering if the bevel set (1 in Picture) and the gear (2 in Picture) on the bevelset pinon is from the 348 or 355 or are they interchangeable. Because i like to order now the 10 groove original shaft with its gearset on it. And need to know if they would fit on my bevel set. Sadly there is no part number on the bevel set visible so i can't identify it. I got only a number from the gear on pinion(2 in Picture) 131248 / E4.

http://img111.imageshack.us/i/020029b.jpg/

 

I got the spareparts after many month waiting. Its a F355 fine spline clutchshaft with 25/29 F355 Transmission Torque Gear Ratio plus a new F355 Bearing ->

http://img338.imageshack.us/gal.php?g=dscf6875.jpg

Now all back into the gearbox and go .....