Engaging low range on the blacktop - Patrol GU -

Submitted: Wednesday, May 28, 2008 at 04:09
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I have a manual 3ltr TD GU Patrol which I use to tow our 2 ton van. As many owners would be aware, the 3ltr has a flat spot in the low revs before the turbo kicks in which puts a bit of strain on the clutch when taking off on hills.

What I normally do is slip the clutch to get things moving but am concerned that this will only lead to clutch damage in the long run.

I mentioned this problem to my mechanic who said to engage low gear and use that to get moving. I mention to him that this would wind up the diff as there would be little slip on the black top. He answered by saying that the Patrol diffs are as strong as nails and would not result in any problems. I'm not too sure if that's good advice so I thought to ask the question of other owners.

Do you use low range on the black top and if so do you engage it when on the move or only when stationary?

It certainly would be handy to use the lower ratios but as I said, I am worried about causing damage to the gearbox or diff.

If you are going to take a shot at Patrols don't bother as all I am after is informed feedback on my problem.

Thanks in advance,

Patrick
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Reply By: Wayne (NSW) - Wednesday, May 28, 2008 at 05:16

Wednesday, May 28, 2008 at 05:16
Patrick,

From your profile I see that you have auto hubs. As soon as you engage low range and move the vehicle, the front hubs will lock in and you will be in 4WD.

If you only travel in a straight line, (don't turn a corner on the hill start), and only travel a short distance, there should not be a problem.

Getting the the gear box out of low range can be a problem. I am sure that you can go from low range to high range on the move but if you still have drive to the front wheels, they will not unlock.

The diffs might be as strong as nails but it is the gear box and tail shafts as well as the diffs that would be put under a great amount of strain.

If you want to use low range on the black top then I would strongly recommend that you swap the auto hubs for manual hubs.
The hubs would be in the unlock position and selecting low range will only put power to the rear wheels and there fore no transmission wind up.

Wayne
AnswerID: 306233

Follow Up By: Member - Roachie (SA) - Wednesday, May 28, 2008 at 09:44

Wednesday, May 28, 2008 at 09:44
Agree with Wayne....fit a set of manual-locking hubs (either AVM or original Nissan Patrol off a DX) and then you can use low range to your heart's content, with the front hubs unlocked. The front drive shaft will turn, as will the diff and internally the axles too....but there will be no drive at the front wheels and no wind-up.

Just a word of caution.....with the drive all going to the rear wheels and the additional torque provided by low range, you just need to be mindful of not trying to put the power down to ground too quickly..... just do everything slowly and deliberately to avoid snapping something in the rear-end.

I've been using this method for many years on my GUs and never had a problem.
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Follow Up By: 62woollybugger - Wednesday, May 28, 2008 at 10:20

Wednesday, May 28, 2008 at 10:20
Do a search on the Patrol4x4 forum & you will find how to easily convert your auto hubs to manual. The "Auto" position becomes free & you turn them to "Locked" to lock them.
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Reply By: Member - Brad G (QLD) - Wednesday, May 28, 2008 at 06:43

Wednesday, May 28, 2008 at 06:43
Patrick,

I have a GU Patrol and the front hubs can be set to 'auto' or 'unlock' using some kind of tube spanner/wheel brace type tool by the look of it. This might be worth looking at before replacing the hubs.

Cheers,
Brad
AnswerID: 306237

Follow Up By: Member - John - Wednesday, May 28, 2008 at 07:49

Wednesday, May 28, 2008 at 07:49
Brad, may I suggest that you have another look at the hubs, "auto and LOCK" not "unlock". May I also suggest that you read your Patrol manual and maybe do a driving course before you go offroad, that is if you plan too. Your comment, "using some kind of tube spanner/wheel brace type tool by the look of it", suggests to me that you need training.
John

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Follow Up By: Spider - Wednesday, May 28, 2008 at 09:20

Wednesday, May 28, 2008 at 09:20
John, thats not a very nice response to Brad. Where's the love?
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Follow Up By: Member - David B (NSW) - Wednesday, May 28, 2008 at 13:46

Wednesday, May 28, 2008 at 13:46
Pardon my ignorance and correct me if I have misread the Nissan Manual incorrectly, but I thought that having the hubs set to the Auto position meant that four wheel drive would engage when you selected high range with the transfer lever BUT this had to be undertaken when your speed was less than 40KMH, but if you set the hubs to the locked position (using the tyre "brace" tool that came with the car) you could engage high range four wheel drive at speeds up to 80kmh.
The benefit in the locked position to me had been that if you were travelling at a reasonable speed on a gravel road and things became dicey you could quickly engage four wheel drive.
There is no difference in moving from 4H to 2H.

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Follow Up By: Wayne (NSW) - Wednesday, May 28, 2008 at 14:23

Wednesday, May 28, 2008 at 14:23
David,

You have understood the manual correct.

If the hubs are in auto, and 4WD was required, just move the little stick to either H4 or L4. The hubs will automatically engage.

If you are in an area where 4WD is required most of the time, select "lock" on the hubs by turning the nut with the wheel brace. This will lock the hubs how ever 4WD will not be engaged until the little stick is moved to either H4 or L4.

Another point. If the hubs are in "auto" and 4WD was selected with the little stick, unless the front wheels are moving, the hubs will not engage. Drive will only go the the rear wheels. The front wheels have to be turning to for the hubs to engage.

If the hubs are locked and 4WD was selected drive will go to the front and back wheels.

Wayne

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Follow Up By: Member - Brad G (QLD) - Wednesday, May 28, 2008 at 18:38

Wednesday, May 28, 2008 at 18:38
John,

I'm glad you can make such a judgement on such a few words. I have actually been 4wding for quite some time. My driver training includes 4wd training with NSW SES and work related driver training with the QPS. Thank you for correcting me on the wording on the hubs - my apologies.

Spider,

I seem to cop crap every time i post on this site. Between the non stop O/Ts and 'whats with the price of fuel?' posts i am wondering if this forum is worth staying with. There are a lot of self professed experts here who seem to enjoy identifying the recreational 4wders. Some just seem to enjoy debating. not me.

Cheers
Brad
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Follow Up By: Anthony (Vic) - Wednesday, May 28, 2008 at 20:17

Wednesday, May 28, 2008 at 20:17
Brad G,
Hang around mate, negative comments on replies are few compared to the positive comments.
I also thought the response you got was poor form.
cheers Anthony
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Reply By: Member - Doug T (FNQ) - Wednesday, May 28, 2008 at 07:39

Wednesday, May 28, 2008 at 07:39
If it's constant 4x4 then a BIG NO NO
if it has manual Hubs then for a short distance won't hurt it with front diff unlocked, and do not engage/disengage on the move.
Most 4x4s have a little sticker on the door ie 2007 Triton , if you find one READ IT.
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Reply By: Member - Oldplodder (QLD) - Wednesday, May 28, 2008 at 07:45

Wednesday, May 28, 2008 at 07:45
Agree with Wayne.

Over a short distance on tar, you can get away with it.

I tow a 2 tonne boat, and there is a hill near us that has traffic lights just before the crest. I always get a red light. Paj has little power under 1500 rpm, until the turbo spools up.

Used to slip the clutch, now I drop it into low range 1st. Get into 2nd low the other side of the traffic lights. There is room to pull over and let others past while I go back into high range. Straight line run which minimises windup.

You are aware of windup, so you will think through what you do, which is good.

On my old paj I used to go low to high and to low again on the move. No syncros in the transfer case, but judge the revs and bit of practise and it works OK.
AnswerID: 306246

Follow Up By: Member - Oldplodder (QLD) - Wednesday, May 28, 2008 at 07:48

Wednesday, May 28, 2008 at 07:48
Better add a note, transfer case works like a crash box, so you need to know how to feel it in, and get the revs right if you are changing low to high on the fly. Can be some painful and expensive noises if you get it really wrong. :o)
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Reply By: Sand Man (SA) - Wednesday, May 28, 2008 at 09:06

Wednesday, May 28, 2008 at 09:06
Patrick,

I can't see where engaging 4WD - low range, will overcome your "flat spot" problem.

If the low gears in 2WD aren't sufficient, I think you need a more powerful vehicle, or a lighter van.

Bill.
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AnswerID: 306256

Reply By: Member - Captain (WA) - Wednesday, May 28, 2008 at 09:25

Wednesday, May 28, 2008 at 09:25
Hi Patrick,

I used to do this when backing my van up my driveway with my manual 3.0TD GU. I needed it more for low speed control rather than any lack of power (1st high was too fast when reversing into a tight spot uphill). But depending on how straight I backed resulted in how easy it being was to get out out of low range.

The way I overcame the low rev flat spot was to add a Dtronic and block off the EGR. Doing these 2 things gives a HUGE boost to bottom end power and I believe adding a 2 1/2" exhaust helps even more. Its something I would recommend - email me for a .pdf on how to block off the EGR along with some other good Patrol tips (compiled by the Nissan forum) if you want (email address in my rig profile).

Cheers

Captain


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Follow Up By: Angler - Wednesday, May 28, 2008 at 20:12

Wednesday, May 28, 2008 at 20:12
I use low range for the same thing, My old man always said the best possible reverse speed is the lowest possible speed. Low range serves that purpose.
Mine is an auto so I don't have the starting problems.
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Reply By: Member - John F (NSW) - Wednesday, May 28, 2008 at 09:33

Wednesday, May 28, 2008 at 09:33
I'm only a simple flight attendant, so prepared to be shot down in flames, but I would be wary of a mechanic who dismisses windup by saying the diffs are as strong as nails.
I thought windup occurred in the drive shafts - I was shown one twisted like spaghetti until snapped by the instructor at OOT 4wd course in Newcastle. It only occurs BECAUSE the diffs are strong as nails...
Having said that, it also only occurs because of different distance travelled by front and rear due cornering, so as others have observed, short distance in a straight line should not hurt. Not sure about low to high on the move, though.

Cheers, John.
AnswerID: 306262

Reply By: westozal - Wednesday, May 28, 2008 at 10:03

Wednesday, May 28, 2008 at 10:03
Hello Patrick,
The best answer to your question is without doubt;
Fit manual hubs (do not engage them of course)to your car and no possible problem will occur given the use of common sense. There will be no windup in the transmission. Obviously you will go back to normal 2wd high range as soon as practable. If you do need 4wd you will have to get out and lock the hubs yourself.
The GU is not constant 4wd.
Ive have used this system in my previous Patrols with man hubs for many years to back up etc. i now own a GU with auto hubs and will change them to manual hubs in due course.
Hope this clears it up for you.
Regards Alan.
AnswerID: 306268

Reply By: Wizard1 - Wednesday, May 28, 2008 at 10:24

Wednesday, May 28, 2008 at 10:24
Why not look at a solution for the turbo lag/flat spot. Get a Dtronic or DP Chip and a larger dump pipe and mandrel exhaust.

Although I have a 90 series Prado, I used to share the driving on long trips in a mate's GU 3.0 TD manual. I too was a little disappointed with the "flat spot" while towing a boat off road. He fitted a Dtronic and it was heaps better.

I like the Patrol, so I'm not slagging them, but the flat spot is a problem with a heavy load. To be honest the 100 series TD is no better and a mate has similar problems with his van on steep starts. I also suggested he get a mandrel exhaust to get rid of the lag and get the turbo spooling up at lower revs.
AnswerID: 306273

Reply By: Member - Patrick (QLD) - Wednesday, May 28, 2008 at 10:38

Wednesday, May 28, 2008 at 10:38
Thanks all for taking the time to respond to my question.

It would seem by the consenious to date that dropping the drive back to low range would only cause problems as I do have auto hubs on my Patrol.

I have already fitted a Dtronic which helps a bit but have steered away from the larger exhaust after much research and discussion with specialists in the field. I know many people who have gone this route and speak volumes on its success but I'll stick to the specialists advice already gained.

I'll just have to stay away from known problem spots so that i don't put myself in the postion of not having the umph to get going.

Any further discussion would be welcomed.

Cheers, Patrick


AnswerID: 306276

Reply By: Member - Glenn G (QLD) - Wednesday, May 28, 2008 at 17:40

Wednesday, May 28, 2008 at 17:40
Patrick
I use low range to pull my boat out of steep boat ramps and to back it up beside the house, as I have the GU 2.8 turbo slug.but I do have manual hubs.
cheers
Giffo
AnswerID: 306340

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