Reverse gear: no power....

[PatrolSlave]

Good day Guys and Girls!
I have a problem that has quite a few people stumped here, and I hope one of you can shed some light...!
I have a 2006 4.8 GRX Auto Patrol with about 110 000 on the clock.
Was trying to reverse up a pavement. The pavement and road is inclined about 20 degrees, and I was reversing uphill (ie nose lower than tail), right front wheel was still on the road and had to lift over the curb. The other three wheels had gone up the slipway (ie no curb). With the right front wheel against the curb, in 2-high, pedal to the metal/on the floor, the 4.8 did not move. The engin revs at 2.5, no wheelspin anywhere... and that is it... My 4.8 Patrol cannot drive over a pavement in reverse....
Forward in 2 high: no problem.
Reversing in 4 high: no problem, but not as easy as I can do it with my manual 2.5 TD Mazda bakkie.
Any ideas PLEASE..???? And please do not tell anyone who drives a LC....
Thanks in advance!

[Stefaansie]

Hi Slave,

Just maybe a pointer, have the selector switch sensor checked out. I had a Hardbody manual that had a intermittand(?) power loss. It had a slight jerk in 4th.
I took it to my gearbox specialist(specializes in auto's and tip tronics) and he reconed that if the sensor picks up its in nutral, the ecu gives less fuel, although the car is in gear. Hope this makes sense.

[PatrolSlave]

Thanks Stefaansie!
That sounds like a good possibility! Will ask the mechanic to check that out first thing tomorrow!
Someone on a forum somewhere said something about the ABS sensors not communicating and therefore preventing the torque converter to do its job. But would then the revs not increase instead of being limited to 2.5??
What do you think about that?

[Jorrie]

[Chris Skinner]

Hi,
I was not quite happy with response on my Patrol when trying do short manouvres, especially reverse, with the heavy boat connected.
I then heard about a mod from someone at the Patrol birthday bash at 3 Provinces, which entailed diconnecting the small lever that adjusts the variable vanes in the inlet manifold. I did a little research on the Aussie forums - and they rave about this mod - its supposed to make much more torque available at low revs. I also made a post about it on this forum.
This is a very simple mod that is very easily reversible by just replacing a circlip. I did the mod and immediately noticed an improvement (I actually did a test by trying to reverse up a curb - much as Slave described in his top post here, and there was an improvement). I decided to wait and see over time whether there were any other visible improvements or negative effects - that was 18months ago and I still have not gone back to original setting. The Patrol is very responsive, it seems to have better handling with the boat on beach etc (but this is hard to quantify). I get really good fuel consumption on average when compared to other patrol users reporting om this forum - I average consistently better that 6km/l on long trips with my heavy and larger than std BFG MT's fitted.
Try it - it really can't hurt!

The original Aussie post that convinced me (see post number 21) :
http://www.patrol4x4.com/forum/diy-modi ... ndex2.html

My post: http://patrol4x4.co.za/viewtopic.php?f=50&t=2161

[Peter Connan]

Despite all the other things that may or may not be wrong, 20degrees is actually pretty steep for high range!

If it really was 20 degrees, you should have been in low range.

One thing to note, unlike most vehicles, the Patrol's reverse gear is higher (IE less powerfull) than first gear, thus it will strugle more in reverse under such conditions.

I would think that if the torque converter was holding the engine to 2500rpm, that system was giving all it has to give. There is no shame in using the short lever, so use it and stop abusing your torque converter! (Note, this comment is only vallid if the slope really was approaching 20 degrees. My car will not do slopes greater than 10 degrees in high range.)

[Schalk]

have your gearbox oil levels checked out its a common problem. with the auto patrols spoke to m boet at nissan said you should check it out.
you can also have your valve bank checked out in the gearbox sump. mcarthy woodmead nissan has the right tools to check the levels on the box etc. the right oil for the box is nissan matic S ATF nr. kle22-00004 if you need to change. also check cooler for the gearbox the pipe sometimes burst and also result in no power. pipes go underneath the patrol from the cooler infront of the radiator. hope this helps

[PatrolSlave]

Good morning!
Thank you for your help sofar!
Schalk: The oil has been checked. The level could not be better nor the oil cleaner!
Peter: As the site in question lies on route to drop the kids, I stopped this morning and measured the incline....
I am ashamed to say... its 7.5 degrees... not close to my estimated 20...
That makes the problem worse I am afraid.
Chris: Thanks I will look into it when this issue is resolved. At this stage I do not want to introduce another variable. I agree however: the Aussies do tinker a lot and really come up with very helpfull "inventions"!

[David]

Here is the fault finding sequence from the workshop manual:

reverse.JPG (170.73 KiB) Viewed 4002 times

Hope it helps

[Wheels]

Possible clutch pack in reverse gear.
http://nissan-europe.epc-data.com/patro ... 315/31500/