Unusual 4wd Problem

[deadly32gtr]

Yer. Im a bit lost now. Should I still get the 265/35/18 front and back this week.

Or should I look into the rims size and all that some more??

And how come Supadan's tyre sizes have never given him this problem? Is his rolling diameter the same on all four corners??

[djr81]

Yer. Im a bit lost now. Should I still get the 265/35/18 front and back this week.

Or should I look into the rims size and all that some more??

And how come Supadan's tyre sizes have never given him this problem? Is his rolling diameter the same on all four corners??

Why don't you just do what has been suggested, pull the fuse on the 4wd system then go for a drive. This will tell you if it is the problem or not.

As a rule you should use the same tyres front and rear on a GT-R. There is no good reason, none at all, for using different sizes.

As for Supadan well chances are his ATTESSA clutch is fkd. Like a lot of old GT-R's.

[supadan]

the rolling diameter is like 2% differance and apparently it with in the limmits off the atezza

[deadly32gtr]

Alright then. Im just going to fit the 265/35/18 front and rear. And hope for the best.

Thanks.

[supadan]

yerthats sounds to be the goods

iam going to 245 40 18 alround but my rim sizes are 8 on the front and 9 on the rear so how much diff would the streching make

[blind_elk]

Thats nearly the same as what deadlygtr32 had!!!! Thats a bit confusing...

deadly had 245/40, supadan has 235/40. It seems to be enough to make no difference to ATTESSA.

Still, you can save a lot of grief by fitting the same size tyres on the same size rims on all 4 corners.

[deadly32gtr]

hey guys...

further to this topic.

after changing my tyres...n got the 4wd switch back on

it started running properly...however after going past 4-5k revs...theres a slight jolt which probably only the driver will feel..and the torque readings on the guage r quite bizzare at times on 1st n 2nd gear.

and also when trying to reverse... the car is getting stuck (locking up) and not moving back...its like something is lockin front wheels from reversing...and this only happenz when im reversing by steering left or right...it reverses in a straight line fine!! The oil is at the right level in my front diff and transfer case!!

my mechanic rekons the front diff transfer case is fu*kd...And even if it is...did it get stuffed because of my tires being the wrong rolling diameter etc..

what you guys rekon?

Thanks for your help!!!

[blind_elk]

and also when trying to reverse... the car is getting stuck (locking up) and not moving back...its like something is lockin front wheels from reversing...and this only happenz when im reversing by steering left or right...it reverses in a straight line fine!! The oil is at the right level in my front diff and transfer case!!

I had a similar thing happen in my GTS4. I can't remember exactly what it was caused by. It was either some sort of fault in the TPS, or it was a poor connection on the alternator.

The ATTESA also activates because it senses some sort of G-force, either through acceleration or cornering. The sensors are located under the centre armrest / glovebox.

[deadly32gtr]

so u rekon the front diff is not stuffed??

And also i forgot to mention...when takin conors and accelerating..the car jerks and makes a slight knockin noise..which is coming from the front wheels..

I just want to know that if my original problem of running the car wid inccorrect rolling diameter tyres etc...has caused this problem.

[blind_elk]

I don't think the original problem has damaged the diff. The R32 seems to be fairly forgiving in this respect. (But, I'm no expert)

The knocking might be something like a failing CV joint. Have you checked all the suspension bushes?

When the ATTESSA pump was replaced, did they bleed the system correctly? And the correct fluid level in the reservoir is checked with IGN = ON.

On a slightly different tack, how old is the battery? Because Skylines are notoriously sensitive to crappy battery voltages (from crappy old batteries).

[deadly32gtr]

Yea iit was bled properly with all correct fluid levels etc.

And the battery is fairly new..only a 5 months old.

its just not only knocking...the car jerks aswell...

my mechanics checked the cv joints boots etc etc..and theyre all fine!!!

The only reason im thinkin that my original problem could stuff up the front diff/transfer is from anotha topic i waz reading under "Drivetrain and Transmission" form with title ""R32 Gtr Front Diff Torque"". Sounds very similar to mine, and mentions in there that by drivin with incorrect rolling diamter can stuff up the transfer case as the it is running all the time, when its not meant to.. and doin so constantly overheats and wears out the clutch plates in the transfer case.

[djr81]

I had some issues with my ATTESSA system.

Turns out the front diff was stuffed.

As were the propshaft uni joints.

And the clutch pack.

And a heap of bearings.

Cost: $3k+ to fix it properly.

Availability of parts: Ex Japan at two weeks (average) except you need two goes because the ATTESSA clutch pack needs a final shim which Nissan Australia don't stock.

First thing to do is to disengage the AWD system & see if this changes the problem.

but the bottom line is you need to take it to a mechanic & get it up on a hoist.

Check the front diff for oil condition & backlash.

Check the front drive shafts & particularly the CV joints. Also the wheel bearings etc.

Check the propshaft.

For my 10 cents worth if the above shows nothing then it sounds like an issue in the transfer case. Which is a pain in the arse to find & fix. Take it to a good/informed/intelligent mechanic & don't expect a cheap bill.

[LAT3RZ]

holy F*CK...ok thanks for all that info djr81.

But can you tell me if all the above uve stated can or couldv been caused by my orginal issue of this topic..of drivin on tyres with a different rolling diameter... i need to confirm that. thanks.

[Godzilla32]

I would highly doubt that different wheel/tyre size could damage any of the mentioned driveline components. Check for metal on the magnetic drain plugs. That will tell a pretty good story of the condition.

In my experience, stick with the same size wheels/tyres on a gtr. Although i have heard of people doing that purposly, something about giving more front torque earlier?!?

[bnr#@]

It will give more front tourque earlier but as the transfer case isnt desighned to work for prolonged periods of time it overheats and wears out. It can happen fairly fast to if its only a small % of power going to the front and not 50/50 as the clutches in the transfer case are sliping to achive that, with 50/50 they would be locked together and not wearing as much

[djr81]

The transfer case has a total of seven clutch plates in it plus the equivalent number of stator plates. When put back together there is supposed to be a small 0.2 mm to 0.5mm clearance when measured as per the manual. When they wear, however, this number can get to over 1mm or worse. This obviously affects the functioning of the 4WD system. You can't tell (other than by seeing how much the car oversteers) how bad it is without pulling the whole gearbox/transfer case apart.

The point I was making was start at the outside at the front & work in. So check brakes, wheel bearings, cv joints, diff etc etc. Go through the system & eliminate the parts from being an issue. Then do the gearbox/transfer case. This is the bit that costs.

[deadly32gtr]

thats what im scared off... The costs. The deal is that when I got tyres to start with. The tyre shop made me put on those tyres even though i told em to put the same tyres as back to the front. And they said it was unroadworthy etc etc. because the tyres were 265's.

From then on the joltin started and since then the 4wd got fu48kd UP!!!! and i changed the 4wd pump and all.. and made up change my rear tyres. The tyre ppl covered all my expenses, coz it was theyre fault. For the 2 new dunlop tyres and 4wd pump and labour.

Now I want to get them to cover my costs for this transfer case or diff, whatever the problem is of my 4WD....But i Need hard prrooof that they're tyre f*k*rz did stuff up my 4wd. To get all my costs covered.

Cheers

[Godzilla32]

It will give more front tourque earlier but as the transfer case isnt desighned to work for prolonged periods of time it overheats and wears out. It can happen fairly fast to if its only a small % of power going to the front and not 50/50 as the clutches in the transfer case are sliping to achive that, with 50/50 they would be locked together and not wearing as much

Yeah i figured it probably would trick the system into thinking there was traction loss in the front.

The Attessa Ets system does work gradually, its designed to operate in a progressive manner. Its not all or nothing. Its anything from no front torque to upto 50% front torque. So what your saying doesnt sound right to me.

[deadly32gtr]

thanks guys. i'l investigate further and give feedback!!!

Cheers.

[b52]

one question, i know we must use same tyre sizes and all for GTR, but what abotu same tyre , same rims, same width, but diff offseT??