Mark, Were you able to locate those weights somewhere to purchase? Sent from my iPhone using Tapatalk
Hi Chip, Unfortunately not, DK Engineering who discovered the weights missing simply invoiced me for 12 Pce bushing without quoting a Ferrari part no. If it would help, I'll go back to them and ask for the details. I did spend a small fortune with them so perhaps they would treat my request positively. Let me know Mark See attached paperwork Image Unavailable, Please Login
Hi Chip and Mark Ive just spent a couple of weeks replacing the TT bearings on my car. I couldn’t find anything wrong with them which was disappointing, but somehow hoped new bearing would fix it. Well it didn’t, it still has the same bearing noise from the TT in P or N together with an occasional rattle when driving and vibration when revving the engine in N. Complete waste of time, but determined to find out what causes it still. Is it engine or gearbox end? Surely someone at the factory knows exactly what it is….
Mark, did the weights help the vibration? I assume they had to take off the flywheel to balance it? Steve
Hi Steve, Apologies for this tardy reply. In all honesty I don't know if they removed the Flywheel or not, all I was told was they found a load of plastic inserts in the bottom of the housing and they had fallen out because the glue had hardened. Regards the reduction in vibration, I initially thought there was a reduction in the vibration and rattle, however, I now think that was more a perception driven from the size of the repair bill than fact..... If and when I decide to tackle the issue again, I will for sure have the flywheel re-balanced. I'll also uprate the engine mounts to ensure there is no vibration coming from the front. Regards Mark
Resurrecting a classic thread… Has there been any breakthrough or discovery with regard to repairing or refurbishment of these automatic boxes? I notice values are still relatively low, so I’m assuming a failed gearbox is still a death sentence for a 456 GTA… Sent from my iPad using FerrariChat.com mobile app
I don't know if there has been a repair "breakthrough" or not with regard to these gearboxes, however, from what I can deduce, they are generally a very reliable unit. That said, you need to look after them like you would with any other mechanical rotating item. I've owned my 456M for 12 years, in this time the gearbox has given me absolutely no issues, until last year, it had only one previous full service in my ownership. I must add I don't do a great mileage as work commitments prevent enjoying the car as much as I should. Despite the low mileage (19,700), I went to the length of having the gearbox oil analysed to see if there was anything untoward happening. The analysis did indicate there was a presence of lead that requires further monitoring, as a mechanical / reliability engineer, I'm not worried with this finding as the lead elements would have acrrued over 20 years in the sump. There is also the possibility the chap who took the sample did so from the bottom of the sump thereby dragging up some rubbish so it may not be totally representative of the units condition. Never the less, I dropped the sump, changed all 3 filters, cleaned everything, and replenished with the recommended Shell oil. I'll sample again after a further 1000 miles to ensure all is well. In my humble opinion, spending £60 pound on oil analysis is a small price to pay to gain an understanding of the condition of your gearbox. I hope this is helpful
It was based on a robust GM unit and shares many of the same parts. I have been into mine fairly deep just to look around and I have changed the rear solenoids and had a look close at the pump. The pump is in the rear since it was modeled after the one used in front wheel drive cars like Northstar setups. I don’t know of any that have failed. Mine has 56k miles on it. I think as long as it is serviced and not abused it should last. Just my opinion though. Sent from my iPhone using Tapatalk
Chip and WMW.....I've just returned from a 1600 mile trip to Scotland and back in my M GTA. The rattle at idle is always there, sometimes really loud and sometimes not so - maybe temperature dependant? There is also general transmission vibration during acceleration at 1750 and 2500 RPM and a noticeable rattle at 1750 rpm when driving gently but not accelerating. I think all these things are connected and I think it's due to the drive line being unbalanced. The rattles I think may be where the front of the torque tube shaft interfaces with the spline coming out of the back of the engine....I may be wrong but if the flywheel is unbalanced and shakes, then this male/female spline joint could rattle due to a small amount of wear. This is just a guess. I'm going to pull the gearbox and torque tube for a second time and remove the flywheel for balancing. Mine also has no anti vibration plugs remaining as far as I can see from underneath. They are listed on ferrari parts stores and look like rubber push in plugs. It lists 6 required although I think there are 12 holes in the flywheel, so every other hole? Not sure if fitting 6 rubber plugs help reduce vibration or you fit them in positions to balance the flywheel....someone must know? The other thing I found is that if gear 3 is selected, it's a bit smoother and more responsive, but in D, the kick down takes a big hard, deep press on the gas pedal to do anything. Is this normal? Lastly, in D on the motorway at say 70 mph, medium to heavy acceleration produces what I would describe as a drumming or judder from the rear of the car. Off the gas pedal and it immediately stops. Gentle acceleration in D is fine, so it doesn't like hard loading on the torque converter?? Going to check fluid level, but may end up pulling the TC for inspection. Frustrating....!!
Let me know on the plugs. I have also wondered about them and if they were set up or actually somehow balanced at the factory. I have had my Torque tube down 3 times so I probably won’t get into it again unless it gets bad. It may be possible to put those plugs in from the opening under the small plate on the bottom of the bell housing if I made a tool to do it. On 3 vs D, I have read that the M’s actually change all the shift points if they are in 3 in a “sport” mode. Unsure since mine is not a M. Sent from my iPhone using Tapatalk
Like you I'm perplexed to understand why Ferrari chose to insert plastic balance weights in the flywheel when most engineering houses would simply grind off metal or drill a few small holes in the flywheel to reduce the unbalanced mass. FYI - I recently took my 456 to a Ferrari Challenge Race day at my local circuit (Snetterton - Norfolk), with the opportunity to take the car on the track, I drove it quite hard for 5 or 6 laps in gear 3 and had a great time. The real bonus however was the torque tube rattle has since disappeared!!! I'm at a complete loss to explain how, or why, the vibration has gone, but it has. The pleasure I now get in driving the car on normal roads and even when stationary at traffic lights in D is like night & day, it feels and drives like a different car. On the few occasions I've driven the car since attending Snetterton, I've had the windows down at every opportunity to see if I can detect a rattle, and I can't even when I'm in D at the traffic lights........I keeping my finger crossed I'm not talking this up and it comes back!!! Regarding the shudder and drumming noise, it sounds like you may have an issue with the TC. If you do decide to pull this down, you may have to send the unit to the USA for strip and repair as I couldn't find anyone here in the UK willing to take on a Ferrari TC overhaul. I'd love to hear how you get on, indeed if you are not too far from Norfolk, I'd happily come over to discuss / view the TT and TC removal Mark
The conversation was all around it being a GM unit, however, here in the UK the even the GM brand isn't as popular as it is in the states. The donar car the gearbox and TC originate from are enigma's to most, if not all UK specialists. I have actually fitted all GM filters to my gearbox which I obtained from a specialist in mainland Europe.
The filters (there are 3) are GM as well as all the solenoids- the shift ones in the bottom and the ones in the back. The pump internals are GM too. All of those can be found on the internet. Sent from my iPhone using Tapatalk
Yes, I managed to secure all the filters from a specialist in Europe and at a reasonable cost too. There was no need for me to delve into the pump as all appeared to be OK, I'm saving that pleasure for the next decade of ownership!!! Dropping the rear valance to gain access to the rear filter was a pain in the bum, however, its done now so I can relax knowing all were changed.
So, I've just stripped the car down again (much faster second time around!) - gearbox out, T Tube out and for the first time, bell housing out and flywheel (flex plate) out along with the splined shaft bolted to the flexplate/crankshaft. Took me a day working on my own. Observations: Having removed the foot long splined shaft from the flex plate, I was then able to insert it by hand into the T tube and feels for any play. Unlike the gearbox end which includes a clamp, the shaft is quite "loose" and there is plenty of play. Inserted as far as it will go, and then shoaling it up and down or side to side I was able to replicate a rattle. This is surely not how it was from new! The TT shaft runs nicely on its bearings and the play is definitely between the TT shaft (female) and the flex plate shaft (male). This end either needs a clamp or a better fit - maybe the splines are worn. Inserting the short shaft into the gearbox end of the TT (the wrong end) produces a much better fit. I may need a "new" short male shaft to a new long female TT shaft..... Of course, it probably wouldn't rattle unless there was vibration in the system (which I can feel), question is where is the vibration coming from? The flex plate has been factory drilled to offset the deliberate lack of crank position sensor "teeth" on one side of the flex plate, but that doesn't mean its balanced. The 12 "lightening" holes around the plate show clear evidence that there where 6 anti vibration plugs once fitted but now missing. As there were 6, I believe they must be anti vibe dampers rather than balancing weights. I'm going to have to find some stock although they list at £60 each for a little rubber/plastic plug about a inch diameter. I'd really like to check balance the flexplate to see if that's the obvious culprit before fitting the vibration plugs. Of course the vibration may be coming from the gearbox end, specifically the torque convertor, who knows.
Thanks for keeping us posted. I have chased this rattle for many years so I am very interested, especially about those 6 plugs. Sent from my iPhone using Tapatalk
Clear witness marks showing where vibration plugs were fitted in every other hole Image Unavailable, Please Login
Thanks for the comprehensive narrative on your investigations, do you have a picture of the splines you mention could be worn? On your ability to re-create the rattle, don't forget the three TT centering bearings have a flexible outer sheath which may allow the TT shaft to move if you apply side to side pressure from the long foot splined shaft. Its good the TT appeared to rotate freely and without any undue noise. I'd expect there to be little lateral free movement between the male splined shaft and the receiving female end. It should however be free to move longitudinally to accommodate thermal growth. If you have "wiggle room" then I suggest one or both could be worn. If Ferrari had truly considered reliability in their design, they would make one spline sacrificial, by that I mean one spline takes all the wear, this is usually the easier & cheaper to replace. I would sincerely hope the splines have been hardened given all the power is transmitted through these so unless there has been some serious misalignment, or your car has travelled "spaceship" miles I can't see these being badly worn. I'm still of the opinion the 6 rubber / plastic plugs are balance weights, however, quite why they appear to have been distributed evenly across every other hole baffles me as normally balance weights are added to counter heavy spots in the rotating element. I have a friend who was a NVH (Noise, Vibration and Harshness) Engineer with the Ford Motor Company in the UK, I'll ask his opinion on the arrangment. At the end of the day to truly irradicate the rattle we must eliminate or be sure we don't have: Parallel misalignment: The shaft centre lines are parallel but are not in line. This can be both horizontal and vertical. The shafts meet at a point, but are not parallel. This can be both on the horizontal and vertical axis. Angular misalignment is also known as gap misalignment. Combined parallel-angular misalignment: A combination of both parallel and angular misalignment. Combined parallel-angular misalignment is the most common misalignment. It would take no misalignment at all to create the condition where vibration is generated, add the possibility of having unablanced rotating elements, and you can see why identifying the root cause is so difficult to most uninformed owners. Once I hear from my friend I'l feedback his comments Good luck with the work and remember....a picture is worth a thousand words
Just as a follow up on my previous reply, if you have stripped the bell housing down, I would as a matter of course change the bearing in the drawing below. Its £20 + VAT in the UK so really a no-brainer to fit a new one thereby potentially eliminating another source of vibration. Image Unavailable, Please Login
It will be interested to hear what your friend says about the anti vibration bush as some websites call it. I can't see that they are balance weights as they are all the same and the flywheel/flexplate is evidently balanced by means of drilling material from the circumference. I have sourced 5 new old stock so far and they are on their way to me. I'm expecting a rubber bush with or without a mass moulded inside to dampen vibration. Rather than take the car apart several more times I've taken the decision to change as much as I can in one go....! I already have a new, unused flex plate which has revealed something of interest already. The plate has 2 or 3 crank sensor castellations ground off during manufacture for whatever reason and this asymmetry needs to be offset by drilling a hole or partial holes on the opposite side.....or so you would think. My original plate with the ground off area at "12 o'clock" has been drilled at 8 o'clock, whilst the new one has been drilled at 5.30....this to me says there is significant variation in manufacturing to warrant such wildly different balancing positions. The movement between the 2 parts that I replicated by hand on the bench by wiggling the short male shaft is definitely not to do with the TT bearings. You can feel very easily with very light force that its the splined parts being a "loose" fit. I'm also sourcing new old stock of the inner prop shaft (TT) and engine splined shaft. When they arrive I can compare the fit with the fit of the ones I took off. If they are similar then I may have wasted my money. If, when it all goes back together, the vibration is still there, then I will have grounds to suspect the TC. And yes, I've fitted a new bearing to the bell housing I'll try to attach a short video - turn up the sound and you will hear the rain!! then the rattle
Your point about the spine arrangement allowing for thermal growth is interesting....I agree with you, however why did Ferrari decide to use a clamp on the gearbox end? Was this to ease assembly and was it meant to be tightened fully to lock the splines at that end on assembly or tightened just sufficently to create a good fit? I need to decide which before I reassemble, but who would know the answer I wonder.
A brief update - whilst waiting for parts to arrive for the torque tube, I thought that I'd better check the rear axle drive shaft CV joints as they felt a bit worn when I manipulated them as part of the gearbox removal. On the bench they didn't see very smooth to articulate and physically were quite rusty. I decided to take one of the apart, having found one new one available from a dealer. As you can see from the photo's the central ball carrier was very distressed at both ends of the shaft. In fact both sides were like this and needed replacement. This could have contributed to the rear vibration felt under acceleration (separate from the TT rumble)
