Vibration when power Send to the Front

[JoKeR33GTR]

Hello, 

Im from germany and i can‘t find the Solution for my Vibration.

I Drive an Nissan Sklyine R33 GTR and i have Vibration when i accelerate .

The Vibration Comes only when power Send to the Front ( Front Torque gauge More than 15%) 

Things i changed already:

new propeller shaft ( Front ) 

new drive shafts ( Front ) 

New transmission bearing 

new oil gearbox , transfer case , Front diff , rear diff

atessa vented 

I Hope someone can help me ..?

 

Good Regards from Germany

Thanks ! 

 

[joshuaho96]

What vibration? You lack specificity in describing the symptoms. The only thing I can imagine causing this is driveline binding from incorrectly sized tires.

[Old man 32 GTR]

I was getting a shudder under acceleration in my 32, ended up being two of the gearbox crossmember bolts were threaded. 

[JoKeR33GTR]

Hello sorry ..

its Hard to describe 

You can feel the Vibration in the steering Wheel and pedals. it comes from the Front / middle to the Front of the car.
the vibrations are always at the same frequency no matter what gear I'm in and only when power is given to the front axle.  I would describe the vibration as pulsing.

[TXSquirrel]

Hmm I would guess that is the LSD chatter.  That means your front diff could be an aftermarket LSD and not the factory open diff, and it's not slipping properly.  Trying adding some friction modifier to the front diff and see if that helps.

[joshuaho96]

It’s possible it is LSD chatter, the driveshaft and everything else in the AWD system is always turning regardless of whether the transfer case is locking up. So whatever issue you’re experiencing is only happening under torque transfer.

[JoKeR33GTR]

Hello Tranks for Your answers!
 

I checked the Front an rear diff ratio and they are both identical. When i checked the Ratio I found that the front diff should be an open one

Tires are new and I also tried another set of tires with different rims and unfortunately it's still the same …

Maybe could it be the Atessa Clutch Packs in the Transfer case ?

( Cars mileage 173.000 km ) 

thanks for helping me ! 

[GTSBoy]

On 4/7/2022 at 7:00 PM, JoKeR33GTR said:

Maybe could it be the Atessa Clutch Packs in the Transfer case ?

I was going to say earlier that the transfer case is a serious contributor to such problems.

[joshuaho96]

On 4/7/2022 at 3:43 PM, GTSBoy said:

I was going to say earlier that the transfer case is a serious contributor to such problems.

What would be the causative mechanism though? I can picture potential issues but everything is spinning whether the clutchpacks are engaged or not. 

[GTSBoy]

Shagged clutches. Chain wear.

[BK]

Lotta plates in there - 19 to be exact between the pressure plates all at 2.0mm thick. Doesn't take much wear across that many plates to cause an issues.

That said I had a problem like this about 10 - 12 years ago in the blue 32. Same thing, developed a noise under load somewhere that we couldn't pinpoint for ages.

On a clutch change we found it by accident when on the hoist - completely stuffed front diff crown wheel and pinion. Happens eventually to most GTR when running the quite ridiculous standard 80w-90 weight front diff oil recommendation, as it causes quite a bit of wear over time.

[djr81]

I had something similar.  Vibration under load.  So give the thing a squirt and see if you can match the front torque gauge to the vibration.

Mine was a pinion/crown wheel on the front diff.

[JoKeR33GTR]

Hello Tranks for Your answers!
 

I'll check the front diff in the next few days.  Yes, the vibrations only come from 25% force going to the front axle.  Maybe the clutch discs are worn out and sometimes not engaging and that's what's causing this pulsating vibration.  What do you all mean ?

[JoKeR33GTR]

With the clutch discs, I mean that they grip, don't grip, grip and all of this at a very fast speed and this creates this frequency because the vibrations are in every gear at the same frequency even at higher speeds

[BK]

I highly doubt it is going to be the transfer case actually. 

[JoKeR33GTR]

BK so you Would Rather say its the Front diff?

[BK]

Look I'm not saying I'm telling you exactly where it is, but you'd have to have done something pretty serious for it to be the transfer. It still might be, but the front crown wheel and pinion worn out or the front pinion bearing are more likely to cause grief before the transfer.

The transfer case internals are pretty over engineered, and had quite a few down for modification before. There are 19 plates inside the clutch - 7 friction and 12 steels in the factory configuration all at a thickness of 2.0mm. I've never ever seen a steel wear out personally and any friction plate wear I've seen has been always been no more than 0.05mm.  Regarding the chain, it is one heavy duty mofo. Definitely seen differences in chain stretch between cases but nothing that was out of factory tolerances - you absolutely would never break one normally.

The only time I've heard of a transfer case friction plate wear out is for 3 reasons - incorrect assembly, no fluid / wrong fluid type used or the most common when torque split controllers are used. Too much torque sent to the front for too long seems to definety kill the friction plates, as the setup was never designed to run with full time 4WD. In this case there are some well documented cases where people have ripped the oeganic friction material clean off the friction plate. Only way this generally happens is from the plate being dry with no fluid, but can happen from prolonged front torque in scenarios where there should be no front torque applied. 1.8 litres of dex III ATF is usually the minimum, but full synthetic ATF like Castrol Transmax Z is a better choice for minimising plate wear. So unless you've been running the transfer dry / low on oil or using a torque split controller set very aggressively there should be no reason for the transfer clutch plates to fail.

Which comes back to the fluids used - what do you use in the drivetrain sections ? The front diff crown wheel and pinion will wear out eventually with a light oil, even with moderate power levels. The pinion bearing can even just randomly fail over time - It's a lot easier inspect the front diff than it is to remove and completely dissemble the transfer case for inspection, so go have a look there first.

I suggest you go for a drive without the front shaft in for a start and see if it goes away.

[Duncan]

without disagreeing about the above, and the risk of being a little off topic....there was that one time I snapped the xfer case chain at Targa in 2007. We put it down to assembly error, made a hell of a bang. AND it stopped me changing gears because it mangled the selector gate so I couldn't eve continue in 2wd

 

[BK]

On 10/04/2022 at 12:53 PM, Duncan said:

without disagreeing about the above, and the risk of being a little off topic....there was that one time I snapped the xfer case chain at Targa in 2007. We put it down to assembly error, made a hell of a bang. AND it stopped me changing gears because it mangled the selector gate so I couldn't eve continue in 2wd

 

Thats gold ! Jesus christ Duncan, how in the hell could you possibly do that ?! That would've made a mess, the only way that could happen is the transfer had to have literally locked up and stop rotating to snap a chain ! There's no way you're breaking one under any normal operation, even with mega power.

Still said it could be transfer as you don't know without inspection, but if it is, it has been caused by what was mentioned. There's some good pics on SAU of a couple of people ripping the friction material clean off, but that is not a common occurrence.

[JoKeR33GTR]

Thank you BK!  Of course I realize that you can't tell me exactly where it comes from, but your tips have already helped me a lot!  I've had the car since 2019 and of course I can't say what the previous owner in Japan did with it.  But everything is series except suspension, rims and exhaust.  One thing came to my mind… I also have vibrations at ~1500 rpm from the Front. When i Hold the rpm at 1500 approx ( car stands and no difference With pushed clutch ) . Last winter i installed a fluid damper without much success... .  During a short ride yesterday, however, I noticed that the frequency of the vibrations is very similar to the other vibrations.