Drivetrain vibration

davy83

Member
Messages
2,809
A 3200 story. I have been suffering with drivetrain vibration for some years and have been gradually working my way through the whole system, starting with the back axle area, 18 months ago I could feel some slack in the rear drive shafts, so I replaced the wheel bearings and drive shafts and had both rear shock's re-furbished. I inspected the diff and was fairly sure its not the source of the vibration so I left it alone at that point. After this work it was better but not solved. So I got under it again and decided that the center bearing that supports the prop shaft seemed to have a bit of movement and so the prop shaft would need replacing. After picking myself up off the floor at the price of a new one, I got a low mileage second hand one from Ireland. I recently got round to changing this and once I got it all apart it was clear that the final drive shaft bearing in the gearbox extension housing was also gone, and i was surprised to find the nut holding the drive coupling to the gearbox had come off completely. I managed to get a replacement bearing and a new shaft nut, but not the oil seal on the extension housing output. I got a seal company to make one up to order and after a couple of aborted attempts got an oil seal to fit. rebuilt the whole thing (prop shaft, exhaust, steering rack, ARB) and it was running so smooth. I was in heaven. And then I took it for a run. The special made oil seal was not made of a high temperature material and softened and started to leak! So luckily after some searching McGraths found a genuine Maserati Oil seal for the gear box and within the next 10 days I will tear it all apart again and replace the oil seal.
Not sure there is a moral to this story other than these cars can try your patience, and if that oil seal on the gearbox of the auto goes, Maserati don't make them anymore so make sure the seal is rated for 220C, the seal size is R40X67X7, and must be FPM or Viton not Nitrile.

rear wheel assy.jpgIMG_20180501_114516.jpg

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safrane

Member
Messages
16,748
So sad to read that simple parts are NLA from the factory.

At least in this case you can get one remanufactured.

Pleased however to see you are on the road again.
 

Gp79

Member
Messages
1,393
Well done for perseverance!

That is a fair amount of work, as above shame maserati don’t try to support older models like the Germans do, but at least parts can be found / matched to keep them on the road.
 

davy83

Member
Messages
2,809
That is a fair amount of work

Well yes it is a fair amount of work and I must admit to not being well pleased that to get the right oil seal in place I am now going to have to do it all again!!! I will post a report with a few photos of this next strip and rebuild for anyone else unlucky enough to hit this problem.
 

highlander

Member
Messages
5,214
Kudos for sticking to it Davy, nice work. Think when marci got the gearbox changed last September Phil mentioned that was the last of the seals he found........Maserati should hang their head in shame not even producing simple seals never mind the more complex bits, shame on them.
 

davy83

Member
Messages
2,809
Well its back together. its running a lot better, and no oil leaks, had a run down to St Cyrus to my brothers place and no problems, so i may have finally got it done. A little vibration at higher speeds but this may be wheel balance or geometry with luck, I would not have noticed with the amount of vibration I had before :) Some pictures Gbox mounting replaced.jpgseal closer.pngseal finally in.pngcentre prop bearing.pngfront coupling.png
 

davy83

Member
Messages
2,809
I should also add that the seal I had made was slightly shallower than the one I got from McGraths. So I suspect if you need a seal made you need R40X67X9, and must be FPM or Viton not Nitrile. The 7mm seal will work but I suspect an 8 or 9 mm depth will be a better fit. I got the special seal from Seal Express and it looks as if it would do the job. Clearly I have not actually tried it in the car because I got the real Maserati one, but I am pretty sure it would work, having compared these two and now knowing about the material temperature spec, I think it would work. Hope this may help some one down the line

Seal Express contact
Richard Jones | Technical sales adviser

Tel: 0121 544 4440 Email:
richard@sealxpress.co.uk
 

davy83

Member
Messages
2,809
For any one who is not bored shitless with this tale, its not over yet. I now have a throbbing vibration (quite different to the initial problem) and to some degree a lot worse and at all speeds, which i presume is coming from the drivetrain, so I got a whole 3 days of driving out of that fix without issues, drove roughly 150 miles, and it all seemed good. I have no idea whats causing this new problem, and I am now more or less resigned to taking it all to bits again and hope some thing obvious turns up. I have been underneath looking for loose bolts and so on and it all looks great. I also this morning dismantled the handbrake assemblies thinking one of the shoes might have separated, and that was not the problem either. I would welcome any suggestions from any one who has experience of the prop shaft or the gearbox extension housing, as to what i might have done wrong here. I may do a quick inspection of the front wheels just in case, but i am pretty sure some thing is up with the new prop, or the replacement bearing and seal on the gear box extension housing.
 

Moz1000

Member
Messages
820
Just a thought - did you mark the propshaft before removing so it went back in the same place? What I'm getting at is is it balanced?
Moz
 

davy83

Member
Messages
2,809
Well i replaced the prop shaft so it was not the same one going back on. IT came off a low mileage car with 32k miles on it. The problem i have now is not balance related i am pretty sure as it ran for 150 miles with little or no vibration up so fairly high speed, and this new throbbing vibration is probably more of an impact or contact sort of feeling and you can here it and feel it even at 5mph its there all the time. My best guess right now is that some thing is wrong at the final drive coupling on the output of the gearbox and i have metal contact some where in there, causing this. Trouble is if i lean on the gear stick i dont feel anything and i would have expected to feel that quite strongly through the gearstick. The really **** thing is to have a look at the gearbox final drive i have to remove everything again and its a bugger of a job.

Just a thought - did you mark the propshaft before removing so it went back in the same place? What I'm getting at is is it balanced?
Moz
 

Lozzer

Member
Messages
2,280
Bugger, You've done 150 miles of it being OK? How bad was the original gearbox bearing? Not bad enough to damage the output shaft I hope. Sounds like something has gone awry pretty rapidly, has it come on all of a sudden or crept in and gradually got worse? . My first thought too was rear brakes as I had it before I changed them, they were partially siezed on the rear, an infrared thermometer confirmed that. If not brakes I would be checking the new bearing to make sure its still ok. Hope it turns out OK.
 
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Rex B

Member
Messages
657
Davy have you looked at the propshaft working angles as it is possible that these could need adjusting (there are some good videos on google which explain).as it is possible that over time these can change due to play in the engine,gearbox and diff mountings, and also if the shimms on the centre bearing were put back differently when the clutch was changed ( manual only) keep up the good work.

Rex B
Manual 3200
 

davy83

Member
Messages
2,809
Hi Rex, yes going to have a look at the angles, i did do my best to set it up but have bought a nifty angle measurement doodad which will get that set up accurately.
 

TimR

Member
Messages
2,656
Did you get this sorted ?
My 4200 has way too much backlash in the drive train for my liking...!
Interested to learn how they can be trouble and tweaked...!
 

davy83

Member
Messages
2,809
Yes i got it sorted it didnt make sense and so the solution was some bolts i had not tightened. stupid really. running quite nicely now. I have bought a proper digital inclination meter so i can line up the two sections of the prop shaft properly and plan to do that in the next week or so.