Good evening. Just thought I'd post this up as Im scratching my head trying to fathom it out. The problem I have is that I only did about 50 miles in the car after purchase before embarking on a full rear end restoration so Im not sure if the noise was there before or not. Anyway, to me it seems that when its running in 4th and 5th gear, there's a chattering noise but only when in lower revs. I have it up on a lift at the moment so if I run through the gears, 1st, 2nd, 3rd no issues, 4th gets noisier and then 5th the worst. If I increase the revs it disappears and and when running at say 3000 rpm / 60-70mph the noise in question disappears again. I did an oil change and also took the inspection cover off and I can't feel any excessive movement on the 4th and 5th gear shaft, no more than would be expected to allow tolerance. The syncro ring and floating rings have movement but I guess thats normal? What Ive also noticed is that if I let the car tick over out of gear and let the clutch up very quickly, I get a (difficult to describe) mechanical churning noise...if that makes any sense (new complete clutch fitted and delivered as a complete unit by specialist) Before I now embark on a gearbox out job, does anyone have any pointers, or in fact want tell me this is normal for a 348? Thanks
This is the ring I was talking about that has movement, but its not a bearing http://www.ferrarichat.com/forum/attachment.php?attachmentid=2088679&stc=1&d=1434740705 Image Unavailable, Please Login
The synchro rings being "loose" when in neutral is normal. The described noise could be just the flywheel rattle. Did you replace the flywheel grease when you changed the clutch?
Yes, all re-packed. The pumpkin housing all came back as one unit. I have to say it does sound like its coming from somewhere around the point between the flywheel and gearbox but not sure why it would be worse in 4th and 5th
If your flywheel was re-packed with Kluber grease than it should not be the cause. Perhaps you should try different gearbox oil. My Getrag 265 box (BMW E30 M3) was making rattling noise when hot and idling in neutral. The rattle would disappear when I just press the clutch and engage any gear (without moving the car). I switched to Motul GEAR Competition (75W140) fully synthetic and the rattle completely disappeared (and this box sees heavy stress as this is my race car).
I just realised that you noticed the rattling while running the engine with the wheels lifted up. You should not test the transmission in this way - almost every transmission will make rattling noise in higher gears if run at low revs with the wheels up. Do a driving test.
If it sounds loudest with a mechanics stethescope just aft of where clutch fluid lines enter the top of the case you might have loose clutchshaft ring nut that on initial hearing could be though of as a T/O bearing. That was the early failure that killed 348 boxes first seen in the challenge cars. Some of those rings where literally not staked by the factory. These cars are very old now and thus a rare failure because all the cars with this problem already had them fixed. It was not a design flaw but an assembly flaw.
I did check the ring nut when I did the clutch and all seems ok, its the type with the locking tab on. I will give it a road test later today and report back. Thanks for all your input so far http://www.ferrarichat.com/forum/attachment.php?attachmentid=2089773&stc=1&d=1434971758 Image Unavailable, Please Login
These topics are interesting, as i think im having some sort of wear/failure in some part of tranny. Symptoms are, 1st, 2nd and 3rd gears produce slight whine when driving light load. 4th and 5th gears are way less noisier. Theres no noises when idling and clutch doesnt affect the sound. I was supposed to check it last winter but didnt had time for it and it didnt change when putting about 3k miles on it this summer. Car has 67k miles on it so dunno if its some normal wear but it does annoy me. I do have some experience about trannys from skyline gtr platform so im pretty comfortable about taking it apart. Guestion is, would you take it apart and inspect the hole unit? Atleast im going to open those side covers and inspection cover to have a minor look I know heres a few guys that have done many these boxes so do you guys have a feel what it could be? Theres no other flaw than that whine i described Cheers guys
STOP driving it and pull the gearbox! If you're not aware, these gearboxes have issues. Take it from me and a lot more on this forum. My 348 is undergoing the same thing right now. 2nd and 3rd gear are getting replaced, along with new bevel gear, synchros, bearings and a new clutch. I have a thread on here which I will be updating along with pics I took at my mechanics shop. Just haven't had the time to do so. If you don't think you can do this job yourself, then bring it to a very well known Ferrari mechanic. Best of luck to you, Vince
Yep, i have read a lot of topics about these issues. And i think i have some part failing in my tranny, im guessing a bearing that affects most to lower gears contact (makes noise) as theres no noise in 4th or 5th gear. Also theres no noise in idle Car is on my garage and i will get it checked, but meanwhile its nice to guess Curious to see what u post ur topic
Went to drain tranny oils and opened inspection plate. Nothing obvious came up, but theres obviously something going on judging by that magnet Image Unavailable, Please Login
Just an FYI, my plug was totally clean. No metal on the plug. The only reason we discovered my issue is that I was hearing some noises in 3rd and after my mechanic riding with me and identifying what I was hearing was possibly an issue, we went ahead and took out the gearbox. Only then did we find the problems You just need to pull out that gearbox and inspect the gears. My car has 35k miles on it.
Will do that. Have u posted pics of your damage anywhere? Would be nice if the gears machined in the shafts were in decent condition, but many times thats just ridiculous hopes
Not yet, might do that later tonight though if I get home from work at a decent time. Haha yes, would be nice
And boom. The ringnut had backed out so much that i could just pull the hole shaft out. Havent seen the gears but dont know, believe they are gone. Well, have to keep stripping Image Unavailable, Please Login
Work progresses, slowly. Has factory used timken bearings or has this box been rebuilt? Im quite surprised that theres not so much damage despite that cutch shaft lockring had loosened fully Image Unavailable, Please Login
Yes, theres some damage at clutch shaft gear. Splines are obviously worn and other face of the gear has rubbed in the casing, gear teeth are surprisingly fine (alto i dont know how much i have lost material of that gear hitting in casing)
Can someone who has un worn gear measure the thickness of it, or just remembers. I would then know how much mine has lost thickness Image Unavailable, Please Login
Have searched alot ot pics and threads but havent found a pic of one of those layshaft bearings (part no: 131334). Issue is mine doesnt have roller cage in it, as 3 other center bearings has. Manual speaks at some tool that keeps rollers place or whatever, so question is has the cage gone south or is it just some weird design not to have cage? Lets keep rollin