Calling Ferrari 348 Gearbox Experts’

Those ring nuts do not look like they are staked too securely to me. I would do the recommended staking posted by FBB or Ernie and go from there.
I think I read on of FBB posts that indicated he likes to see the metal tear and put the staking ring against the innermost part of the notch. IF you remove the ring nuts ask FBB how to reinstall them. It is apparently very important to have really clean thread surfaces and use lots of Loctite 271 and a special tool to tightne the ring nuts.

BT

 

They kind of give the appearance that the nut has started to back off. Perhaps it's just the way they were staked. Mine was a little worse but caught in time. Cost me $6K in parts alone just to replace my 3rd gear synchro. We did the clutch also which raised the parts price by about 2K. Please secure yours better while you have the opportunity.
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Well since you have it torn down this far, I would go ahead and remove the second cover on the oil pump side of the box. That's the side in your bottom 3 pictures. The side with the phonic wheel for the speedometer sensor. The out side of the bearings can look fine, but behind that second cover can show if the bearing is starting to fail. So remove the second cover and have a look at the bearings underneath it.

 

Yup.

You can take off the second cover. The main and lay shaft will not drop because there are also bearings inside the gear box holding them up. If memory serves me correct you will need to remove the phonic wheel as well as the ring nuts. Just be careful with the little "seal" that is on the end of the shaft where the phonic wheel is. Not the snap ring, but the seal at the tip of the shaft. You can snap off the little hooks, or snap it in half, if you aren't careful.

Lane also posted the other ring nut you'll want to check out. It's on the flywheel side of the gear box. You'll need to remove the clutch bell housing to get to it, but that comes off in one piece. While you are at it I would replace the triple seals, since they will be right there anyway.

When you get to putting the covers back on use some Hondabond HT to seal things up. That's what I used and I have absolutely no leaks from my gear box.

 

They look like they have been changed on the oil pump side... Regardless, if you are there already, you need a 56, ringnut tool and a left and right threaded ringnut. To take the one with the phonic wheel off (don't snap the seal ring) you loosen it clockwise, and the one on the oil pump shaft Counter-clockwise.

When you take those nuts off and loosen the retainer frame for the bearings, then you should be able to pull the bearing cage off with the bearings sliding off the shafts. They will not drop in as they are kept in check by further roller bearings about 1/3 of the way in from both sides. You will get a little lateral play (which is what those bearings are meant to prevent, hence they being thrust bearings).

They don't look like they have backed out. In the disassembly you may find the races jammed onto the shafts andif you pull hard the bearings will open up causing a major mess. I'd opt for pulling out the dimples, tightening the ringnuts up and then staking them so the metal on the face opposite the losening direction is broken right onto the cutout on the shaft. This will prevent them from ever coming off, with or without locktite (but some may argue). Regardless this is in lieu of removing the whole GB and doing a "proper" job where you remove and change the bearings and ringnuts (about USD500 all in and a day's work) thereby ruling them out altogether.

You can pull out the clutch shaft without taking the gearbox out by heating around it and pulling on it with a vise clamp. That has a ringnut and drop gear which if not tight can cause enough movement to collapse the plines requiring a new set of drop gears and a shaft. The assembly will require a complete gearbox take apart to get to. So doing it at this stage is a no brainer...

 

If your're talking about the clutchshaft ring nut it is right hand threaded. Righty-Loosey Lefty-Tighty

 

Oops I meant LH threaded. CW to remove and CCW to tighten.

 

Paul - Not sure where you're at on the gearbox, but if someone used Loctite 271 on threads, you have to heat the Loctite up with something like a propane torch to get the Loctite to loosen up. Or perhaps a hi-temp heat gun. So if you're turning things in the correct direction (look at the threads themselves to see which way they are angled), then you could try a little heat to see if it helps. Try to be careful to watch that something doesn't catch fire... with all the oily surfaces in the gearbox. Hope this helps.

 

hi there could any body tell me where the best place to 348 gearbox fix in the uk or is it best to buy a 2nd had one cheers Andy street