43% or 85% reduction gears for 4.5 Auto

[Go the Nissan]

hi all

i've read the thread in the bible about the transfer gears.

I want to be able to go down hills without touching the brakes. At the moment the GU is an Elephant on skates. Having read the thread, i'm leaning towards the 85%.

But down the bottom 'AndrewPatrol' fitted 43% and said it holds alot better down hill and still allow 60km/h in low range.

My questions are these:

Does anyone know what speeds i can get in a 4spd auto with 85%????
The reason for this is i go to Fraser Island a bit and the soft patches (Indian Head) you just need the pulling power of low range and a bit of speed/momentum as well. I'm worried the 83% will give me fantastic engine braking down hill but no speed left.

'Andrewpatrol' or anyone else that can answer this question, How good was engine braking with the 43% gears. Do you still feather your brakes, can you walk next to your vehicle???

I use the GU at 4wd parks, going to sand islands etc.. pretty much everything.

Anyone able to give us some advice on which way to go.

Thanks in Advance

[raptorthumper]

I would strongly urge you to go 85% for autos. On very steep hills i would doubt 45% would be enough. I think the 45% ratios are more for the guys who do mostly mud.

As far as deep sand goes the 85% still gives you heaps of speed in 4th (overdrive switched on). The best part is you have 4 gears, all close ratio and the auto bangs through them quickly with full throttle on.

I will let you know what speed mine does at 4500 rpm low range 4th. I really dont think it's an issue. You can use 1st or 2nd high range as well if needed. You can pick a suitable gear from that.

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Cheers
Grant.

[raptorthumper]

Just checked and i still have 3.9 diffs and 33" tyres. 85% reduction gives the following in 4th overdrive low range.


approx 65km/hr at 4500rpm

and about 70 km/hr at 5000 rpm.


Plenty of speed for sand to stay in low range for petrol motors. Revs are a bit too high though for those speeds with diesel.

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[Go the Nissan]

Just checked and i still have 3.9 diffs and 33" tyres. 85% reduction gives the following in 4th overdrive low range.


approx 65km/hr at 4500rpm

and about 70 km/hr at 5000 rpm.


Plenty of speed for sand to stay in low range for petrol motors. Revs are a bit too high though for those speeds with diesel.

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That's awesome. Thanks for that mate.
i think i'll be getting the 85% gears.

Out of interest. Would you go a winch or a front diff locker first?

I already have a locker in the rear.

[GQ Bear]

Good thread as i'm pondering the same thing. I have decided to go reduction gears instead of diff ratios in tb42e gq with 35's off road.

Being a manual transmission, petrol and a lot of mud driving in Vic, would i still be better off with 85%, or should i go 45%?

And if i did go 45% would i regret it further down the track if i ran 37's with 4.6 diff gears?

What are the differences b/w Marks and Rockhoppers? Is one better than the other? Easier to fit? etc,etc?

Thanks

[AndrewPatrol]

Just to clear things up a bit. I have the ZD30 with 4 sp Auto and its got 4.3 diffs as standard. I went the 43% gears so that I dont have to stop and change up to high range at too low a speed. I always felt low range wasnt quite low enough. Diesels have have slightly better natural engine braking anyway. The petrols dont have such a prob cos of 3.9's. It goes plenty slow down most hills but the steep ones it wont hold - but I get around that by using left foot braking. Up hill is much better for crawling. The 85% gears would make every thing slower and still allow a big jump in play tyre size before running out of LOW range again. I dont plan to go any bigger than 35's in future any way, cos of other factors, GofG, braking etc.
Would have loved the opurtunity to compare though, not that I regret the 43%.

[AndrewPatrol]

gotta add that I was a bit worried about putting extra strain on front axle and cv's etc with 85% and big wheels, the further you go in each direction the more pressure, not that i've heard of any probs, I just didnt wanna increase the chances of being the first.

[GUEEY]

I have 83% Rockhoppers.

IMHO i belive the 43% would suit vehicals set up for standard offroading with a large variety of conditions.
If i had my time again i would go 43%.
the Rockhopper 83% are awrsome in extreme climbing and desending, but are a huge pain in the arse when many of the offroad driving that we do is not extreme!
Contary to one of the above posts i belive you cannot drive in low range to the next hard track. My GU 4.5 is screaming its arse off at 25-30 Kph at 4-4500rpm, then once i shift to high range my truck on 35 claws wont pull the skin of a rice custard!
43% would give you alot more gearing in low range for the majorrity of track drivin off road.
If any one is considering 83-85 % redution gears come and drive mine in low range before you make a decision you may regret.

Cheers Grant

[raptorthumper]

GUEEY you dont say if you have manual or auto. Just checking.



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[Mick.]

Just checked and i still have 3.9 diffs and 33" tyres. 85% reduction gives the following in 4th overdrive low range.


approx 65km/hr at 4500rpm

and about 70 km/hr at 5000 rpm.


Plenty of speed for sand to stay in low range for petrol motors. Revs are a bit too high though for those speeds with diesel.

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I wish I could get that speed out of mine. My 4.2 carbi GQ auto only gets about 30km/h in low range with the 83% redution gears. I've only used it once on sand since fitting them and I cant use low range on the sand anymore because it's just to low.

Cheers Mick.

[Mick.]

I have 83% Rockhoppers.

IMHO i belive the 43% would suit vehicals set up for standard offroading with a large variety of conditions.
If i had my time again i would go 43%.
the Rockhopper 83% are awrsome in extreme climbing and desending, but are a huge pain in the arse when many of the offroad driving that we do is not extreme!
Contary to one of the above posts i belive you cannot drive in low range to the next hard track. My GU 4.5 is screaming its arse off at 25-30 Kph at 4-4500rpm, then once i shift to high range my truck on 35 claws wont pull the skin of a rice custard!
43% would give you alot more gearing in low range for the majorrity of track drivin off road.
If any one is considering 83-85 % redution gears come and drive mine in low range before you make a decision you may regret.

Cheers Grant

I agree 100%. 83% is over kill for my auto and i'm running 37s. So I think 43% would have suited myself and 99% of other better than the 83%.

Cheers Mick.

[raptorthumper]

Bullshit.!!! Bullshit.!!! Bullshit!!

I have to say it.

Check again. An auto in 4th and low range with 3.9's does 65km/hr at 4500 with 85% gearmasters.

Someone back me up here and check theres.

Test for yourself.

Heres Grungles homepage with the specs on gearbox and diff ratio's from factory for GU series.


http://www.mcs.net.au/~grungle/specifications.html



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[Mick.]

Bullshit.!!! Bullshit.!!! Bullshit!!

I have to say it.

Check again. An auto in 4th and low range with 3.9's does 65km/hr at 4500 with 85% gearmasters.

Someone back me up here and check theres.

Test for yourself.

________________________________________________

I got the GU diffs out of a 2.8 litre desiel in mine (what ever ratio they are) and there is know way in hell it will do anywhere over 30km'h without reving the shit out of it nad thats with 37s on it.

[GUEEY]

GUEEY you dont say if you have manual or auto. Just checking.



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Sorry Dude!
MANUAL

[ergjan19]

I agree with you raptor humper i could probably get to about 60kmh if I was revving the tits off it. It sits conforatably at about 40kmh in overdrive, low range in a 1998 GU auto with the 83% reduction.

[currentlyoffline]

I think you all should maybe put your speeds in context by posting

1. Diff ratios
2. Auto/Manual
3. Diesel/Petrol
4. 2.8/3.0/4.2/4.5/4.8
5. Tyre Size

You maybe disagreeing on a few different points here

[raptorthumper]

Mick your stuck in 2nd gear mate.!


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[ats4x4dotcom]

Im fitting the 43% to my 05 GU manual TDI and I have fitted 4.88 diffs to go with the 37" Xterrains for touring. 43% reduction makes for great vic high county low when needed, and the 4.88's make standard gearing with the 37's.

To work out your rpm/gearing/speed try here for engine to axle speed, which easily then converts wheel speed to rpm.

http://www.marks4wd.com/Nissan-GQ-GU-ex ... -gears.htm

[Madmac]

Bullshit.!!! Bullshit.!!! Bullshit!!

I have to say it.

Check again. An auto in 4th and low range with 3.9's does 65km/hr at 4500 with 85% gearmasters.

Someone back me up here and check theres.

Test for yourself.

________________________________________________

mymanual GQ with 85% gears will only do a top speed of 40kmh in 5th, with 35s and 3.9 diff gears

[raptorthumper]

Petrol or Diesel . ? Petrols can rev a bit harder.
Manuals are geared lower in top gear. Your vehicle should do over 50 km/hr at 4500rpm and over 60 km/hr at 5000rpm.

unfortunately the program wont let you input tyres bigger than 31.83 inches.

see below.








I checked as i said with my actual vehicle but here is the proof.






Download and install this program. It's called topspeed and calculates vehicle speed and other engine parameters like compression ratios etc. Very handy little tool.


*************** Fixed link*******************
http://www.kamware.com/TopSpeed.exe
******************************************

then right click on the following links and save to your hard disk (under my documents is the dfault look in place).

These files contain gearing of various 4wd vehicles.

Then start topspeed from programs folder and click on calculations then gearing. Then click load and select one of the files you saved to your disk . ie GU patrol 4500 auto. You will need to rename the downloaded files so they only have file extension .ger


http://grantm.customer.netspace.net.au/ ... manual.ger

http://grantm.customer.netspace.net.au/ ... 00auto.ger

http://grantm.customer.netspace.net.au/ ... 00auto.ger

http://grantm.customer.netspace.net.au/ ... manual.ger


This program doesn't lie and you can change engine speed, tyre size etc to suit your vehicle.

85% Marks gears are 3.74:1

83% Rockhoppers are 3.70:1

std nissan low range is 2.02:1



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[bogged]

Going down a hill not using brakes at all you say?

Do you currently use low range a lot for just crusing round the high country, or whereever for example? If so, think of what a pain in the arse and fuel economy 85% would be... you would stop change hi/low low/hi all fuckin day since IMHO standard low range is a good ratio/speed for normal driving around some areas where you are in and out of difficult situations.

If your a comp dude where most days only consist of 100klms TOPS of driving, then yes it would make sense, but for a normal 4b, I dont see the value.

I'm not totally sold on them at all. In a perfect world twin cases would be the ideal option as you keep your normal low range, which is very good speed/ratio more often than not.... but with tailshaft issues for daily driver it aint a great option..

[raptorthumper]

Bogged. Low range is good up to 50 km/hr cruising but revving a fair bit.

Lets face it 50 clicks on most mountain trails is honking a long. If it's smooth and fast sure i will stop and select high range, but at least decents are a doddle in any one of the 4 gears and the auto doesn't get hot working hard on steep rocky inclines.


Choose whatever turns you on.

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Grant.

[bogged]

Bogged. Low range is good up to 50 km/hr cruising but revving a fair bit.

Lets face it 50 clicks on most mountain trails is honking a long. If it's smooth and fast sure i will stop and select high range, but at least decents are a doddle in any one of the 4 gears and the auto doesn't get hot working hard on steep rocky inclines.


Choose whatever turns you on.

Grant.

Yup. have no issues with mine in the bush with stock t/case, and 33s on 4.3s...

[raptorthumper]

Bogged,

Your opinion surprises me. You go against the opinions of just about every 4wd reviewer in the country including Ron Moon and many others.

In every comparison of Patrol vs Landcruiser vs whatever Low range gearing is assesed and for many people this is a factor they consider when purchasing. Reduction is not the be all and end all but in almost every review auto patrols are criticised for lack of low range gearing.

Thats fine your happy with std gears. You can keep the $1250 bucks in your pocket. Maybe you dont like to see your beloved diesel rev past 2500 rpm. (stirring the pot)

As for GUEEY, Mick and Hiluxmadness. Feel free to to provide updated speeds in low range.

I guarantee the speed program is correct. If you provide figures make sure you note (manual/auto), rpm, tyre size, transfer gears, diff ratios, and speeds in km/hr plus what gear you are in.

Go the Nissan, wanted know if he would have enough speed with 85% reduction for fraser island in deep sand. I posted true figures of what he can achieve if he gives his petrol a good rev in 4th low range, (same vehicle as mine).



__________________________________________________________
Grant.

[GUEEY]

Bogged,

Your opinion surprises me. You go against the opinions of just about every 4wd reviewer in the country including Ron Moon and many others.

In every comparison of Patrol vs Landcruiser vs whatever Low range gearing is assesed and for many people this is a factor they consider when purchasing. Reduction is not the be all and end all but in almost every review auto patrols are criticised for lack of low range gearing.

Thats fine your happy with std gears. You can keep the $1250 bucks in your pocket. Maybe you dont like to see your beloved diesel rev past 2500 rpm. (stirring the pot)

As for GUEEY, Mick and Hiluxmadness. Feel free to to provide updated speeds in low range.

I guarantee the speed program is correct. If you provide figures make sure you note (manual/auto), rpm, tyre size, transfer gears, diff ratios, and speeds in km/hr plus what gear you are in.

Go the Nissan, wanted know if he would have enough speed with 85% reduction for fraser island in deep sand. I posted true figures of what he can achieve if he gives his petrol a good rev in 4th low range, (same vehicle as mine).



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Grant.

i tried downloading your program , but it came up with an error.
ener this figuires for me on your program.
GU 4.5, 4.1 gears and 83%rockhoppers, 5 gear 0.8 @ 4000rpm ( i am not prepaired to rev my truck any harded for constant cruising in 5th in low range, even 4000rpm is a little high for my liking)

thanks Grant (too)

[bogged]

Your opinion surprises me. You go against the opinions of just about every 4wd reviewer in the country including Ron Moon and many others.

The difference is, Im not paid to sell products. My theory is hit me dont shit me. Say it how it is. I'm also not fooled by whats written in magazines. One mag says Product A is THE BEST and product B is the worst. The next maggo says completely the opposite.

Honestly, when was the last time you saw a test on something in ANY magazine(4wd, fishing, model trains) that said it was a true piece of shit? they dont.. if they did they would never get another product to test from that company.. So reviews are not objective. They cant be, its the nature of the beast. maggos are between a rock and a hard place.

In every comparison of Patrol vs Landcruiser vs whatever Low range gearing is assesed and for many people this is a factor they consider when purchasing. Reduction is not the be all and end all but in almost every review auto patrols are criticised for lack of low range gearing.

Mines not a new patrol, its a 91 GQ, so current reviews mean shit comparing mine. (Just on this, my new GU the normal gearin (manual) is hideously close and low, where you could almost get away without 1st)

I have also changed diff ratios to match the tires. While this doesnt really make a difference it brings it back to standard... On the long weekend heading down through the HCountry to Upper Jamieson Hut, its a nice slimey downhill that goes down on a decent angle for a while, I had no problems.. Probably dabbed the brakes 3-4 times when coming to a washout/or erosion hump what ever you call them so I didnt smash into them (all cars did the same), but not standing on the picks or riding them on the way down. I would say thats very acceptable.

dont get me wrong, its not perfect in EVERY situation, but neither is a manual, or rockhoppers.

There is NO perfect...

But in most I have come across, I've been happy with it. Thus why Im happy to go Auto in the TD6

Thats fine your happy with std gears. You can keep the $1250 bucks in your pocket. Maybe you dont like to see your beloved diesel rev past 2500 rpm. (stirring the pot)

I will keep my $1200, and I dont really like mine revving past ~3000-3200.. no need for it, its not a high revving petty donk.

[Vulcanised]

i have standard transfer gearing in mine, 3.9 diffs and 35" tyres... it does have engine braking down hills in low 1st at about 10kph but it does have some..... in an auto i don't see the need to go that far with gearing.... mine struggles a little on the road with 3.9's even with the V8, but off road it has no problems.... 4.65 diffs will make it a bit better down hills, and i can still drive most of the time in low range. With the torquer converter locked up (i have a manual switch for it) i could achieve around 120kph in low range if i wanted to push it that hard..... or unlocked i should get about 70 to 80kph at or near redline. Keep in mind the V8 has a red line about 1,250rpm higher than the Nissan 6...... "IF" you can get 60kph out of the vehicle in low range with the reduction gears... WHY would you want to drive your vehicle at redline just to keep up?

[raptorthumper]

Bogged. Good reply, you clarified your opinion.


GUUEY, sorry the link to the program was broken.

Try this.

http://www.kamware.com/TopSpeed.exe


also here it is calculated with 31.83 inch tyres. With 35's you are about 50km/hr at 4000rpm.






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Grant.

[zookjedi]

i intialy had this same dilemai but i dont drive sand, have 4.5 auto 3.9 r/p 33" and 35" tyres with the marks 85% gears , i dont use the car for comps , i use it for camping general 4x4ing and what ever comes up , i personaly believe i would have kicked my self had i had bought the 43% gears , the auto does it all so easy. You shouldn't be going over i thought it was 40kph in lowrange as per visor sticker or it could be 60 kph im not sure , but still with the auto there is no problems getting past 40 , i carn't see how going between hi and lo and vice versa between areas is such a big deal for those that dont wanna drive at a moderate to slow pace , or for those that dont want to rev there engines .

i guess everyone is different , hence there are two differnt reductiond now avalible , but if you like to drive some of the harder stuff in 4x4 parks etc not just sand than i would be going towards the 85%


as for locker or winch ? i went dual arbs but i dont go out by myself if i did i would go a winch .

[Go the Nissan]

Thanks for everyone's replies.

I take them all into consideration but replies from people that actually have a 4.5 (GU obviously) petrol AUTO with 33" are especially relevant.

I tried mine in low range (stock) and I had it up to 100km/h. It still had a bit to go if i wanted it to. So hitting 50km + is not unrealistic with 83% reduction.

Thanks again everybody