GU4 4wd selection difficult
Submitted: Thursday, Sep 15, 2005 at 14:07
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26482
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Rokkitt
Hi,
Hoping someone could help me out with some advice regarding 4wd selection in my 2005 Nissan Patrol GU.
4wd is simply difficult to select at first, once it has all lined up it seems fine (after 4wd has been selected once). I am generally unable to get it into 4wd whilst moving, often it gets caught between 2wd and 4wd high, grinding loudly until I stop and select 4wd.
It states in the manufacturers handbook that I should be able to select 4wd h at speeds of up to 40kmh but this is not the case - I have managed to do this once in the 23000kms I have travelled and that one time it just dropped through perfectly.
At each service so far I have made a point of mentioning this but they do not seem keen to investigate instead "greasing the linkages" time and time again which only works as long as it is all lined up. Several k's in 2wd seems to be enough to put it out of alignment and causes the problem to return.
On my last visit to Nissan which was specifically for this problem they advised that I can only select 4wd when the front hubs are locked - not in the auto position; but common sense is telling me that this should not be the case and I should be able select 4wd on the move in either the auto or locked positions.
I am not a mechanic by any means and I am finding it very difficult to resolve this when I am continually fobbed off by Nissan with excuses that seem almost unbelievable - the service personnel advised to lock the hubs before I leave
home so it is ready when I arrive at my destination eg departing
Melbourne to go to
Mansfield which goes against all that I have been advised.
Also I have noticed the car steams up very badly at the first
sign of rain, is this a sure
sign there is a leak - this has also been tested by Nissan on both the 1000 and 10000k servces - to
test it they spray a hose at the windscreen and then advised me there is no problem.
Any advice or information would be very much appreciated. Should I be demanding action and taking this to the highest power possible or are they correct in there advice? has anyone else had similar issues?
Regards
Rokkitt
Reply By: Member - Roachie (SA) - Thursday, Sep 15, 2005 at 14:51
Thursday, Sep 15, 2005 at 14:51
G'day mate,
There is NO WAY you will be able to change from 2wd into 4H "on the fly" unless you have manually locked up the front hubs with the spanner.....not even at low speeds.
Think about what is happening uner there for a minute........As you drive along (even at a modest speed of say 40k/h), the rear tail shaft is spinning at a considerable pace, whilst the front tailshaft hangs around doing sweet fanny adams. So then you reach down and want give the stubby lever a quick jerk to put her into 4x4. That little shaft is expected to go from zero rpm to umpteen rpm (to match the rear tailshaft speed) in a millisecond..........I DON'T THINK SOOOOOO.
The whole idea of the auto locking hubs is in case you find yourself unexpectedly stopped in a mud puddle and going no where.......don't wanna get out and get the old suede shoes all muddy, so (being already stopped totally), THEN you reach down for the stubby lever and rip her back to 4x4 (either 4H or 4L) and have a go at getting out of the shyte. Of course, if you KNOW that you are possibly going to need to get into 4x4 at some stage of a particular trip, it is wise (IMHO) to lock the hubs up and that way you can do it on the fly.
I know the advertising blurb is a bit misleading and they tend to forget to tell you that in order to avail of the shift on the fly feature you MUST have the hubs locked up before-hand.
I am very surprised you say you were able to do it once @ 40k/h.....I reckon your hubs must have been locked in at the time.
Cheers mate
Roachie
AnswerID:
130239
Follow Up By: baza - Thursday, Sep 15, 2005 at 15:02
Thursday, Sep 15, 2005 at 15:02
Have to disagree with you there. Around my property I regularly go from 2H to 4H on the move - about 30k/hr, with the hubs in auto. No grinding etc. Just put some pressure on the stick, lift of the throttle and in she goes. The manual/instructions also indicate you can do it.
FollowupID:
384709
Follow Up By: Exploder - Thursday, Sep 15, 2005 at 18:09
Thursday, Sep 15, 2005 at 18:09
Well I’ll be stuffed; I always thought that is why Nissan had the auto locking hubs on the GU, for switch on the fly operation.
I.E> I can go from 2WD to 4H at anytime at speeds up to 90km/h, however 4L I must come to a complete stop and if I try to select low range at speed or in gear it will simply just not engage.
FollowupID:
384728
Follow Up By: Rokkitt - Thursday, Sep 15, 2005 at 22:40
Thursday, Sep 15, 2005 at 22:40
Exploder,
Is that with the hubs in auto? behind the drivers sun visor it clearly states "shift on the fly" at speeds of up to 40kmh - although I must say I was sure the manual stated otherwise - take the manual on the train tomorrow for a read and see if I can find it.
Just doesn't make sense - why the difference to the label of "locked and free" as a certain other breed.
Rod
FollowupID:
384779
Follow Up By: Rokkitt - Thursday, Sep 15, 2005 at 23:01
Thursday, Sep 15, 2005 at 23:01
In addition:
I may not have made myself clear but after the first difficult "crunching" shift all successive shifts are fine - at least after an attempted first shift on the fly we are forced to stop immediately due to the crunching and select 4wd, could the front shaft continue spinning after going back to 4wd?
Admittedly I have been pushing down with the palm - just tried it.
Thanks
Rokkitt
FollowupID:
384785
Follow Up By: Rokkitt - Thursday, Sep 15, 2005 at 23:05
Thursday, Sep 15, 2005 at 23:05
Oops - I meant "could the front shaft continue spinning after going back to 2wd?"
FollowupID:
384787
Follow Up By: JamieMac - Friday, Sep 16, 2005 at 08:36
Friday, Sep 16, 2005 at 08:36
The Manual states you can shift from 2wd to 4wd with hubs unlocked in auto mode at up to 40kmh and if the hubs are locked it is up to something like 80-90kmh.
I have not been able to do it but I have a mate who assres me he has no trouble. Mind yo I have found it stiff on my car even when completely stopped but have been waiting for it to free up
There must be some synchro type device that gets the propshaft up to the right speed perhaps by using the hubs to accelerate it. It only tkes a half a turn or so of the prop shaft to engage the hubs in auto mode.
Jamie Mac
FollowupID:
384810
Follow Up By: Leroy - Friday, Sep 16, 2005 at 08:59
Friday, Sep 16, 2005 at 08:59
there's no syncro. The front prop shaft won't be spinning unless the hubs are locked. Once the hubs are locked it'seasy to shift between 2h and 4h because both drive lines are spinning at the same speed.
Leroy
FollowupID:
384814
Follow Up By: JamieMac - Friday, Sep 16, 2005 at 10:48
Friday, Sep 16, 2005 at 10:48
Leroy
Classic (old) design of 4x4 would say this is the case. There may
well not be a 'synchro' but something makes it posssible to engage 4wd with hubs in auto as it can be done.
Do you know what type of device it is? A slight turn of the shaft can engage the hubs. Perhaps they have a clutching action to spin the prop shaft up to full speed?
Pajeros do it through a much more comlex setup than I believe the Patrol has. Perhaps those who have the manual for the Patrol could enlighten us further.
Once hubs are locked by manual or auto means it is indeed very easy to go between 2wd and 4wd at speed providing the rear wheels are not slipping too much. This is why a lot of poeple advocate putting the clutch in to do so altghough it is not necessary to do so.
Cheers
Jamie
FollowupID:
384839
Follow Up By: Exploder - Friday, Sep 16, 2005 at 16:48
Friday, Sep 16, 2005 at 16:48
Sorry Rockkitt for slightly misleading you, I don’t have a patrol as the name suggests I have a Explorer, which apparently has a much more complex 4WD system, My hub’s are fully auto and I think they use some sort of spring or electro magnetic system to engage/ disengage them.
The 4WD system will also do some other neat stuff to keep you out of the chit like automatically slip into 4H when the rear tyres loose traction and then disengage once slip is no longer detected.
FollowupID:
384886
Reply By: Member - Duncs - Thursday, Sep 15, 2005 at 15:16
Thursday, Sep 15, 2005 at 15:16
Rokkit,
The easy one first. My 2001 model Gu needs the demister on with A?C at the first hint of rain too, as did my wifes 2000 model SUbie. to solve this problem I simply moved from those horrible wet
places near the coast and now live in
Broken Hill where rain is not a problem (lack of rain is).
Now 4wd Selection. I don't know if you have ever had the front hubs apart on your GU, I am guessing not. On a normal free wheeling hub there are splines on the end of the drive axle which engage with the wheel when you lock the hub. When unlocked and driving along these splines are stationary and the driven part of the wheel is spinning. When you engage 4wd this drives these splines are then droven by the transfer case through the front diff. In my minds eye I see the driven part of the wheel and the splines on the drive axle spinning at different speeds and going crunch as the auto lock hub tries to engage. I would suggest that this is also what is making selecting 4H difficult. I find it is actually easiest to engage when I am almost but not quite stopped and I have my foot on the clutch. I think this is because it allows the splines to find a comfy fit without too much pushing and shoving
When you lock the hub manually you remove this from the equation. This is because with the hubs already locked, the front diff and drive shaft will already be spinning at the same speed as the rear and it is easier for the drive gear in the transfer case to mesh with the out put to the front which is also spinning at the same speed. On my GQ I did many
miles with the front hubs locked and the transfer case in 2wd. This does have a cost in higher fuel consumption but when travelling over constantly changing ground made life easy. In 8 years of ownership the only time that car gave me grief from the hubs was just after they had been serviced, that's another story. On the old GQ I could happily change from 2wd to 4H at speeds of up to 100km/h all I ever had to do was lift my foot off the throttle for a moment and in she went. I have not tried this on the GU but from my basic understanding of how the system works (I am no mechanic either) I can't see it being a problem, provided the front hubs are locked manually before I try it. I do have difficulty occasionally engaging 4wd but it is usually when I am trying to rush things.
Hope this helps but if someone more qualified than me has an opinion I am happy to listen.
Duncs
AnswerID:
130243
Follow Up By: Rokkitt - Thursday, Sep 15, 2005 at 22:36
Thursday, Sep 15, 2005 at 22:36
Hi Duncs,
Thanks for your response, also answered my question about when the clutch should be operated - I guess I am very new to this, I had an auto NH pajero previously and never had a problem shifting. Guess I was kind of expecting the same with the "shift on the fly" advertising.
Your explanation is extremely comprehensive and you claim not to be a mechanic, it all makes perfect sense - actually felt a bit of a dunce as I read through it. As a credit to Nissan - basically as it was explained to me whenever I asked about although not as clear and comprehensive, maybe reading it makes more sense too.
Thanks for you time anyway.
Rokkitt
FollowupID:
384774
Reply By: Rokkitt - Sunday, Sep 18, 2005 at 21:22
Sunday, Sep 18, 2005 at 21:22
Success,
After a day in Lerderderg - Success, dissapointment at being shown the ropes by a prado.....lol.
Their is certainly a "technique" to it.
Many many thanks to all those that responded to this question.
Apply light pressure to the little stick, dethrottle and pop - in she goes, and out time and time again.
Nissan service techs advised this could not be done "without the hubs locked" I will take great pleasure in demonstrating what a special car
mine is and offer them many thanks for the free extra! I can shift with the hubs in the auto position "on the fly"
Thanks again
Rokkitt
AnswerID:
130721
Follow Up By: Leroy - Monday, Sep 19, 2005 at 12:25
Monday, Sep 19, 2005 at 12:25
I had a bit of a play on the weekend also and managed to 'shift on the fly' without the hubs locked but in auto. Not sure if it was becasue I was on an extra slippery surface (snow) or not but had no probs. But I did try a couple of times when i first got the patrol and just got that grinding noise and couldn't ease that stubby stick into 4wd.
Leroy
FollowupID:
385223