4wd Problems?

[GTR-80Y]

Can anyone help? Started having some problems with the gearbox or transfer case. When i drop the clutch a little harsh theres a loud crunching/grinding noise. Happens in any gear if u pop the clutch too quick.

Also not sure if this is related but the 4wd torque split guage reads a slight amount of power being sent to the front wheels when cruising at speeds over 60kph.

Any ideas?

[T04GTR]

normal

[ebola]

Also not sure if this is related but the 4wd torque split guage reads a slight amount of power being sent to the front wheels when cruising at speeds over 60kph.

Any ideas?

NOT normal. I cruise at 110 (ish) for hours at a time... I'd wear out my centre clutch if it did this

check your tyre diameters - they should be the same. The fact that this only happens at speed makes it likley this is the issue.

rsvp

[JonesyGTR]

NOT normal. I cruise at 110 (ish) for hours at a time... I'd wear out my centre clutch if it did this

check your tyre diameters - they should be the same. The fact that this only happens at speed makes it likley this is the issue.

rsvp

When I am cruising, my torque gauge always reads that there is some split to the front as well. If you accelerate, the amount becomes more. I was under the impression that this was meant to be the case. Can anyone confirm this, or set the record straight?

My tyre's are all equal - not differing sizes.

Cheers,

Dan

Edited October 16, 2006 by R32 GTR PWR

[Duncan]

Definately not normal to have torque cruising in a straight line....front torque is based on either difference in wheel speed (ie wheel slip, different sized wheels or maybe different wear front to rear) or the reading from the longitudinal accelerometer....ie when you are accelerating strongly.

We have never really measured what "strong" acceleration is for the standard computer, but if the sensor was not mounted straight (ie on an angle) or the rear of the car was lower than the front, it might read as acceleration all the time.

[JonesyGTR]

Definately not normal to have torque cruising in a straight line....front torque is based on either difference in wheel speed (ie wheel slip, different sized wheels or maybe different wear front to rear) or the reading from the longitudinal accelerometer....ie when you are accelerating strongly.

We have never really measured what "strong" acceleration is for the standard computer, but if the sensor was not mounted straight (ie on an angle) or the rear of the car was lower than the front, it might read as acceleration all the time.

If it is not normal, and I am to assume that there is a fault with something on my car (ie sensor mounted incorrectly) what is the best way to confirm this? Can you help as to where the sensor is and how it should look/be mounted? Or perhaps someone/somewhere that would know?

Thanks in advance,

Dan

[saliya]

Hey,

on my 32 GTR, there's no drive to the front while cruising. I understand that because of preload

the 33s and 34s are different.

Note that even if there _is_ drive to the front wheels (say, 50%) as long as all the wheels are

rotating at the same speed there should be no wear on the clutch packs...

Regards,

Saliya

[den001]

there shouldnt be any movement oin the torque guage while cruising, its was intended to reduce rear wheel traction loss, thus it doesnt engage massivly, only gradually unless the clutch is dumped.

ive noticed if u r cruising and u hit a big bump or somthin on the road, it engages the fronts and stays like that until u let the accelerator go. then it drops

[ebola]

Note that even if there _is_ drive to the front wheels (say, 50%) as long as all the wheels are

rotating at the same speed there should be no wear on the clutch packs...

Unless you want to turn the front wheels to any angle other than 0 degrees... then there is wear, be the diff open, limited slip or locked (??).

[saliya]

Unless you want to turn the front wheels to any angle other than 0 degrees... then there is wear, be the diff open, limited slip or locked (??).

(...in which case all the wheels won't be rotating at the same speed... )

Regards,

Saliya

[GTR-26R]

ive noticed if u r cruising and u hit a big bump or somthin on the road, it engages the fronts and stays like that until u let the accelerator go. then it drops

all R32 GTR's iv been in have all done this mine included! not sure why

[JonesyGTR]

all R32 GTR's iv been in have all done this mine included! not sure why

Where abouts does the needle on the ones you have been in sit when you are cruising at highway speeds?

Dan

[gun32gtr]

yeh my 32 does this also

[PhilGTR]

Mine had this too a while back when my front tyres were more worn than the rears, but I just got 4 new tyres that were even and no more torque split unless I gun it.

[GTsauRus]

When I am cruising, my torque gauge always reads that there is some split to the front as well. If you accelerate, the amount becomes more. I was under the impression that this was meant to be the case. Can anyone confirm this, or set the record straight?

My tyre's are all equal - not differing sizes.

Cheers,

Dan

when I put new tyres on the front took it for a hiway run and at 100k I could feel the car surging, looked at the torque meter and it was pulsing up to about 10% same frequency as the surging, went back to town and took notice of the torque, on gentle acceleration big torque was dialing up so drove to the tyre place and got new rears, viola back to normal no surging and only see torque under hard acceleration or wet roads never on cruise.

the manual quotes the maximum tyre diameter difference allowed i will look it up i ur interested.

[GTsauRus]

Mine had this too a while back when my front tyres were more worn than the rears, but I just got 4 new tyres that were even and no more torque split unless I gun it.

it happened on mine when the fronts were bigger than rears. new rears fixed it

[gts4diehard]

my R32 GTS4 always showed zero when cruising, only ever showed torque to the front when accelerating or rears spinning. Never had any probs with the 4wd system in the 180,000kms the car had put up by the time I sold it.

Perhaps the additional power/heat generated by the GTR is reducing the performance of the transfer case fluid. Don't the AU sold GTRs have additional coolers fitted for the transfer case?

Test Scenario;

1 - gauge is incorrect

2- clutch pack activated too early

- incorrect transfer fluid viscosity

- old/contaminated fluid

- wrong fluid

- insufficient fluid level

- attessa pump system not releasing pressure from previous

activation

- G-force sensors giving wrong readings causing early activation

- Tyre diameters don't match giving computer impression wheels are

spinning.

Maybe its the gauge playing up, you could try removing the 4wd fuse which will cut out the 4wd and the abs for a bit to make sure the gauge can read Zero. Check the site for particulars on doing it.

IF the gauge is working correctly then somehow the car is activating the the FWD - maybe fluid is old and thicker and changed viscosity is activating the clutch packs - a fluid change is in order for the transfer case.

maybe there is the wrong fluid type in transfer case which is activating the clutches due to incorrect viscosity.

maybe fluid level is low and clutch packs are heating up and gripping

Is the attessa fluid level correct - check the resovoir in the boot (RHS) with the ignition on. See workshop manual for correct operation.

Other than that remove the centre console and have a look at the g-force sensors, from memory they will show if they have been subjected to a hard knock - see workshop manual for particulars.

A bit too check but the gauge should be zero when just cruising.

[JonesyGTR]

Thanks for the helpful input guys, this is what I have found so far:

With 4WD fuse out the car reads 0 (as you would expect).

The tyres are all 17's HOWEVER, they are differing brands with, you guessed it, slightly different diameters.

So know I am going to try and get two changed to the same size, or put 4 tyres the same on to test.

The smaller ones are at the rear. If I put them to the front, would that help/change the situation?

Cheers guys, I keep you updated on progress.

Dan

[PhilGTR]

Actually I did at one stage put new tyres at the front and and old tyres at the back and i had no problem. But with old at front new at back i had the problem. You can try swapping them around first

Thanks for the helpful input guys, this is what I have found so far:

With 4WD fuse out the car reads 0 (as you would expect).

The tyres are all 17's HOWEVER, they are differing brands with, you guessed it, slightly different diameters.

So know I am going to try and get two changed to the same size, or put 4 tyres the same on to test.

The smaller ones are at the rear. If I put them to the front, would that help/change the situation?

Cheers guys, I keep you updated on progress.

Dan

[godzl1975]

mine does this for some reason too...after changing to a new set of rims...i think it could be the tyre diameters arnt the same...not as in width but diameter, will have to check. Had track day not long ago and put on the old rims with semi slick on the rears and didnt show a reading at all while just cruising.

Would this be really bad for the clutch pack in the transfer case with it having some load on it while cruising?