Reduction Gears

[katwoman]

1. What are they, where do they go, how do they work ?
2. What do the % mean ?
3. Will they affect daily driving ? Loss of power, ect
4. Is there another option to slow your descent ?

I would like to hear from those who have them, had them, fit them, sell them or invented them. If you could explain in the least technical way, that would be good.

[BigRAWesty]

1. What are they, where do they go, how do they work ?
2. What do the % mean ?
3. Will they affect daily driving ? Loss of power, ect
4. Is there another option to slow your descent ?

I would like to hear from those who have them, had them, fit them, sell them or invented them. If you could explain in the least technical way, that would be good.

1- they are a reduced gear which replaces your low range gear in the transfer box behind the gearbox.
To be honest the biggest let down of the patrol is its gearing ratios.
When selecting low range in a patrol you really only gain 1 extra gear and second gear low is already above first gear high. (hope that makes sense)
So that's when your percentages come in..

2- the figures your seeing are a percent of reduction. You can't have 100% or you would not move.
85% is quite common in qld as they love rock climbing. But that's not such a great option if you in the high country.
So there are other options to suit your needs.

3- no they won't affect anything when in high range. Except your wallet when purchasing lol

4- reduction gear will aid hill decent to no end. Your engine (depending on what it is of course) will be able to hold the speed down with less force. Same with acceleration, your gears are a lot lower so taking of on steep hills is easier.

Hopefully I haven't confused you.
In sort say your sitting on 50k/h in low range 5th gear. By adding a reduction gear set that speed will be slower in relation to the percentage installed.

Cheers

[macca]

Kallens done a great job of explaining.

I fitted the 43%?? to my manual 4.2, the difference is incredible. Sometimes getting moving in low one was a challenge, no longer.

The mates in cruisers were heading up hills in low two where as I was always in low one, I had no other options so the clutch copped a beating. Decent is more controlled as well.

Reverse is lower too which is a pain at times but not really too much.

Basically the low range half of the box got shifted one gear, two became the old one, three became the old two etc. Most importantly 1 became a lower and much more useful gear.

A whine comes with the gearing upgrade but that's normal and only really noticeable in low four / five.

Hope that makes sense.

[matfew]

not sure what % benne got but he couldn't use 4th or 5th when he was with us in high country as in those gears the whole gearset is spinning to fast and makes a horrid noise. pretty sure he's got the 80% though.

[Drewboyaus]

not sure what % benne got but he couldn't use 4th or 5th when he was with us in high country as in those gears the whole gearset is spinning to fast and makes a horrid noise. pretty sure he's got the 80% though.

Yes, Ben has 85% which is almost too much for high country....someone around here added the custom 65% ones from a group buy and is loving them.
Just thinking, he might have done diff ratios too but can't remember.

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[MudRunnerTD]

Hi Kat,

Yes as Matt states when Bene was down it was quite apparent that his 85% reduction gears were a real problem for him in our type of terrain. He struuggled with the touring type speed of the high country in Vic. His gears were a little under. Crawling up the hard stuff though was rediculous!!

43% could be a better option and there has recently been a group buy for some custom 63% gears but I think that's done.

I assume you are chasing a little most reduction from your TD42 which is surprising to be honest as in a manual they are pretty good. I would be more inclined to consider a Diff Gear change.

From factory you will have either a 3.9 or 4.1 gear set. Mine is 3.9. I would love to swap out to a set of 4.3s for a great touring and climbing set. This will raise your revs slightly in hi and low but will really make a big difference if your running 33s or 35s. That's where my money will go.

What are you after. Just decent control?

Good luck mate.

[macca]

I assume you are chasing a little most reduction from your TD42 which is surprising to be honest as in a manual they are pretty good.

Certainly not my experience, but with the pod etc mine is heavier than a wagon and 33" tyres are fitted so that could be the reason for our different points of view.

[MudRunnerTD]

Certainly not my experience, but with the pod etc mine is heavier than a wagon and 33" tyres are fitted so that could be the reason for our different points of view.

I am running 35s and have 3.9 gears in the GUIV. It ain't great. My GQ running 35s and 4.6s holds first with no brakes down all but the steepest of steep. Then the odd tap of the brakes gets it done. Running 33s on the GUIV and it's pretty good, 4.3s would be awesome though. I have even thought about going to 4.1s but if I am going to spend the cash the 4.3s would get my money.

Reduction gears will make a dramatic different right through your low range. Changing diff gears make a subtle to big increase in hi and low range. I think swapping diff gears would be better value.

[macca]

There were some 4.3 centres on eBay recently, I will try and find them for you

[macca]

There they are, Sorry about the hijack Kat.

Front diff
http://www.ebay.com.au/itm/111504221089?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649

Big diff??? like mine???
http://www.ebay.com.au/itm/221603178021?ssPageName=STRK:MEWAX:VRI&_trksid=p3984.m1423.l2661

A pair
http://www.ebay.com.au/itm/Diff-Centres-4-3-ratio-Front-Rear-Pair-for-Nissan-GU-GQ-Patrol/111480536535?_trksid=p2047675.c100011.m1850&_trkparms=aid%3D222007%26algo%3DSIC.MBE%26ao%3D1%2 6asc%3D20140107090050%26meid%3D9cef1db92593449689a 264366be4c805%26pid%3D100011%26prg%3D2014010709005 0%26rk%3D8%26rkt%3D10%26sd%3D221603178021

[MudRunnerTD]

Cheers Macca. Spent all my cash on. Guns and Scopes :) but Kat that gives you a bit of a price bracket. Steve can fit them no trouble at all. If you patient then you will find a front and a back for a good price and sort it out.

[nissannewby]

"Love ke70" is the member who did the 63% run and I believe he is currently doing another with a set costing $1400 in the group buy.

[BigRAWesty]

That's just for crown and pinion to though so a lot more is required installing them

[katwoman]

Thanks for your replies, guys.
Basically, when I did Billy Goats the other week, I found I was riding the brake quite heavily going down, where as the non-turbo 60 hardly even touched his. I've been finding this more and more as I do the steeper sections. Katrol just goes too fast in low 1st. I'm not sure sure what to do about it. So changing diff ratios may do the same as reduction gears ? The higher the % the lower the gearing ?

[Winnie]

Kat diff ratios will change your high range as well. I have done billy goats load of times and did not find myself using the brakes at all

[katwoman]

Kat diff ratios will change your high range as well. I have done billy goats load of times and did not find myself using the brakes at all

Yeah, see thats my prob.... Not sure why it is too fast..

[MudRunnerTD]

Yours is a Manual isn't it Kat? Have a look at your compliance plate for your diff ratios.

If you increase your diff ratios it will affect you hi and low range. When you take off and through each gear in high range you will find it a little more tourquie. A bit more punch. The gears will feel a little shorted though but bang for buck you would love it. In 5th you might see 200rpm increase in cruising speed which, if your running bigger tyres will put you back in your Boost sweet spot. They will give your car new life day to day.

In low range it will be a little punchier too and your engine braking will improve. It should improve just enough. It's about drivability. I think the reduction gears would give you the sh1ts in the Vic High country the rest of the time.

[Maxhead]

Hey Kat, I kind of disagree with Dazz. Keep all your gearing the same and just go with either 43 or 63 reduction gears, You will love the slow 1st low, kind of the same as the toyoys.lol
If you change your diff ratio you'll be reving the shit out of it when cursing. Not worth it.

Unless you run big tyres then YES, you need to change your diff ratios

I'll be doing the reduction when I can afford it as even the manuals tend to run away on a decent down hill:O)

[katwoman]

Yours is a Manual isn't it Kat? Have a look at your compliance plate for your diff ratios.

If you increase your diff ratios it will affect you hi and low range. When you take off and through each gear in high range you will find it a little more tourquie. A bit more punch. The gears will feel a little shorted though but bang for buck you would love it. In 5th you might see 200rpm increase in cruising speed which, if your running bigger tyres will put you back in your Boost sweet spot. They will give your car new life day to day.

In low range it will be a little punchier too and your engine braking will improve. It should improve just enough. It's about drivability. I think the reduction gears would give you the sh1ts in the Vic High country the rest of the time.

Thanks Daz, yeah it's a 5 speed. I turn the gas off and the A/C on, which makes a small difference, but not enough. I'll look into it when I get home from work. So changing the ratio will only affect 4wd ? Not 2wd ? Would it tow better as well ?

[katwoman]

Hey Kat, I kind of disagree with Dazz. Keep all your gearing the same and just go with either 43 or 63 reduction gears, You will love the slow 1st low, kind of the same as the toyoys.lol
If you change your diff ratio you'll be reving the shit out of it when cursing. Not worth it.

Unless you run big tyres then YES, you need to change your diff ratios

I'll be doing the reduction when I can afford it as even the manuals tend to run away on a decent down hill:O)

Crap, I hate it when not every one agrees.... I run 33's. Dont plan on changing that any time soon...

[Winnie]

Thanks Daz, yeah it's a 5 speed. I turn the gas off and the A/C on, which makes a small difference, but not enough. I'll look into it when I get home from work. So changing the ratio will only affect 4wd ? Not 2wd ? Would it tow better as well ?

Diff ratios will affect 2wd as well Kat. It will make towing better for sure.

[Maxhead]

Crap, I hate it when not every one agrees.... I run 33's. Dont plan on changing that any time soon...


Yezah, but Dazz is a bozo and has no idea about stuff...LOL just kidding BTW!
IMO, I wouldn't ferk with diffs with 33's and just whack reduction gears in. Patrols suck with low gear compared to Toyoys:(

[Winnie]

The diff ratios are only going to change your low range by bugger all though, reduction gears are the answer if you are worried about your car running down Hills. I would love to have the 43% reduction =)

[MudRunnerTD]

I appreciate what Kris is saying for sure. Remember he drives a CRD3.0. The TD42T is a different animal though. if you have the 3.9s then they are looow. this is what i have and great for the flat hwy but in the igh country i tend to go to low range and use 4th and 5th allot rather than struggle in hi 3rd dropping back to hi2nd all the time. sluggish. running 35s is worse and with the trailer on drop another gear.

The diff ratios will make the car Tow with pleasure too. Should not bog down as much, will take off easier and pull up hill better with a load on.

[Ben-e-boy]

Diff ratio change wont even come close to a transfer case gearset.

A cruiser has a factory ratio of approx 2.8:1 a patrol has 2.02:1. A cruiser low range is so much better than a patrolSo if you installed 43%ers it would take your low range to (if my maths is right) 2.88:1. My 85%ers take my low range to 3.74:1

85% is for crawling they dont go fast but will tractor along all day

Example.
I have 35 inch tyres, 4.11:1 diff gears, a first gear ratio of 4.556:1 and transfer case gear ratio of 3.74:1

At 800 rpm I have a crawl ratio of 70.03:1. In the ute as it stands

With stock transfer gears and the same everything else I gave a crawl ratio of 37.82.1

With 43% gears my crawl ratio is 53.93:1

Compare that to a diff ratio change.. (dont forget these figures are based on my ute)

If I left the stock transfer gears in and changed the diff to 4.3. I have a crawl ratio of 39.57:1

As above but with 4.6:1 diff gears I have a crawl ratio of 42.33:1


As you can see the transfer case gears make a much bigger difference than just diff gears for low range

Most of this little climb is done at idle, with 85% gears......no speed just tractor :D

http://youtu.be/CL0aNOQO71o

[Maxhead]

Yes, I should have considered the motors but I thought the running gear ratios were the same...oops:) Hmmm

[macca]

Swapping 3.9's for 4.3's is a change of about 10%. Not enough for off road engine braking that you are after. The diff change comes into its own on road with bigger tyres or towing as mentioned. Running 33" tyres is borderline for a ratio change, be good with 4.1 diffs possibly. But reduction gears offer more for the money spent. This is my experience and thoughts, made the decision to do the gears for the same reasons you are looking into this. Good luck.

[MudRunnerTD]

I was not suggesting Diff gears would be comparable to transfer gears by any means though Bene. As per your maths there is a massive difference.

So the big question is How Much reduction does Kat really need. That's the point I am making I suppose. Winnie stated he can go down Billy goats with hardly any braking. The odd tap and that's enough, low first holds well. I bet he has 4.1 diff gears and it gets the job done.

If Kat has 3.9s and is chasing her brakes down the same hill then she may really only need a sublte change to achieve her aim. Going to 4.3s will give her what she is chasing. No it still won't be as low as the 60 but should crawl pretty well down Billy Goats. The bonus would be the extra torque in hi range for when towing.

If you can pick up a pair of 4.3s for $600 or so and Steve throws them in for the win I think your next trip up and down Billy Goats would be very different.

[MudRunnerTD]

Yes, I should have considered the motors but I thought the running gear ratios were the same...oops:) Hmmm

Yours would be the 4.3s that I'd be recommending.

[Winnie]

Well Kat, it's settled. Swap out your diff ratios and get a set of reduction gears, win win =)

I've got no idea what diff ratios I have? Stock 93 TD42 manual gears whatever they are

[Ben-e-boy]

I was not suggesting Diff gears would be comparable to transfer gears by any means though Bene. As per your maths there is a massive difference.

So the big question is How Much reduction does Kat really need. That's the point I am making I suppose. Winnie stated he can go down Billy goats with hardly any braking. The odd tap and that's enough, low first holds well. I bet he has 4.1 diff gears and it gets the job done.

If Kat has 3.9s and is chasing her brakes down the same hill then she may really only need a sublte change to achieve her aim. Going to 4.3s will give her what she is chasing. No it still won't be as low as the 60 but should crawl pretty well down Billy Goats. The bonus would be the extra torque in hi range for when towing.

If you can pick up a pair of 4.3s for $600 or so and Steve throws them in for the win I think your next trip up and down Billy Goats would be very different.


That took me over an hour to write that post so it wasnt really a repky for anything recent.. For reduction gears the 43% will be basically on par with a cruiser.

As for diff gears just get the equivelent of a stock final drive ratio with the bigger tyres. So 3.9 stock with 33s just take it up th 4.11

[MudRunnerTD]

That took me over an hour to write that post so it wasnt really a repky for anything recent.. For reduction gears the 43% will be basically on par with a cruiser.

As for diff gears just get the equivelent of a stock final drive ratio with the bigger tyres. So 3.9 stock with 33s just take it up th 4.11

Bhahahahahahahahah. I thought you talked like that all the time!!!

[Winnie]

Bhahahahahahahahah. I thought you talked like that all the time!!!

He just thinks you're a knob and you don't know what you're talking about =)

[katwoman]

Well Kat, it's settled. Swap out your diff ratios and get a set of reduction gears, win win =)

I've got no idea what diff ratios I have? Stock 93 TD42 manual gears whatever they are

Good-O..... I'll add it to the list then, shall I ?? There goes my new lawn mower.

[BigRAWesty]

Katwomen are you running a petrol?
If so then yea you will have less engine breaking compared to a diesel, but again the Toyota have a good gear ratio setup so if your compairing a gu petrol to a 80 series diesel you'll loose everytime when riding engine down hills.

Imo if your running larger tyres do the diff gears. It'll return the car setup back to close to stock ratios.
If your running stock tyres and want a bit more then look at your low range reduction gears.

But in saying that if you have to touch the break it's no big deal. Just plan when, don't ride them and be gentle.

So now that we've confused the shoit out of you. What's your thoughts lol

[Winnie]

Katwomen are you running a petrol? If so then yea you will have less engine breaking compared to a diesel, but again the Toyota have a good gear ratio setup so if your compairing a gu petrol to a 80 series diesel you'll loose everytime when riding engine down hills. Imo if your running larger tyres do the diff gears. It'll return the car setup back to close to stock ratios. If your running stock tyres and want a bit more then look at your low range reduction gears. But in saying that if you have to touch the break it's no big deal. Just plan when, don't ride them and be gentle. So now that we've confused the shoit out of you. What's your thoughts lol she has an almighty TD42 Patrol and is comparing to a 60 series diesel...

[katwoman]

Katwomen are you running a petrol?
If so then yea you will have less engine breaking compared to a diesel, but again the Toyota have a good gear ratio setup so if your compairing a gu petrol to a 80 series diesel you'll loose everytime when riding engine down hills.

Imo if your running larger tyres do the diff gears. It'll return the car setup back to close to stock ratios.
If your running stock tyres and want a bit more then look at your low range reduction gears.

But in saying that if you have to touch the break it's no big deal. Just plan when, don't ride them and be gentle.

So now that we've confused the shoit out of you. What's your thoughts lol


Thanks for that. I kinda know the basics as I had a petrol auto 4.5 before I bought the 'queen' of patrols. So, I just really wanted to know the info for my TD42, as Winnie so kindly stated.
I still have some people I need to speak to and check out what diff ratios I have, so I'll mull over it until the new year. Funds this time of year wouldnt let me make a decision any way.

[jay see]

After the Tallarook drive I've discovered how sh!t the low range is (4.5 auto). Having owned a diesel Toyota again auto, the low range is much better. It would have to be 1/2 the speed of the patrol, so the 43% reducing gears are probably the closest to it.
Dame another thing to add to the list.

Has anyone changed theirs. Is it just a straight swap one out one in or is there more to it.

The patrol is too fast and dangerous going down hills, at lest with the Toyota you can click 2nd gear if its not fast enough.

Marks have them for $1350 will have to wait and see how good the tax man will be next year.

[Drewboyaus]

After the Tallarook drive I've discovered how sh!t the low range is (4.5 auto). Having owned a diesel Toyota again auto, the low range is much better. It would have to be 1/2 the speed of the patrol, so the 43% reducing gears are probably the closest to it. Dame another thing to add to the list. Has anyone changed theirs. Is it just a straight swap one out one in or is there more to it. The patrol is too fast and dangerous going down hills, at lest with the Toyota you can click 2nd gear if its not fast enough. Marks have them for $1350 will have to wait and see how good the tax man will be next year.

There is a technique for "driving through the brakes" that all auto drivers should learn if you don't already know it. Can descend almost anything without drama. I would also consider a torque converter lockout (in an auto) before reduction gears otherwise you still won't get the direct drive you need to take advantage of the reduction gears.

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[Agronaught]

After the Tallarook drive I've discovered how sh!t the low range is (4.5 auto). Having owned a diesel Toyota again auto, the low range is much better. It would have to be 1/2 the speed of the patrol, so the 43% reducing gears are probably the closest to it.
Dame another thing to add to the list.

Has anyone changed theirs. Is it just a straight swap one out one in or is there more to it.

The patrol is too fast and dangerous going down hills, at lest with the Toyota you can click 2nd gear if its not fast enough.

Marks have them for $1350 will have to wait and see how good the tax man will be next year.

Looks like there is a little case modification needed for the reduction gears, but I'll probably head down this path as well as the low range isn't really low enough IMHO. Its getting a little stiff on the small lever anyway so probably time for a transfer case rebuild.

[BigRAWesty]

I think the case needs a little clearance for the bigger 80 whatever reduction. Pretty sure the 43 fits in nice

[macca]

When my 43% were fitted the mechanic aid a little trimming was require for clearance.

Knew that was the case for the 80%, maybe he was being cautious.

[jay see]

There is a technique for "driving through the brakes" that all auto drivers should learn if you don't already know it. Can descend almost anything without drama. I would also consider a torque converter lockout (in an auto) before reduction gears otherwise you still won't get the direct drive you need to take advantage of the reduction gears.

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Yes I know about this, but physically I can't use my left leg for that purpose, if I could I would be driving a manual without a doubt.

[Crate]

Also I noticed on patrol4x4 Marks are also doing 63% reduction gears. They have a group buy going atm. Would be the reduction I would get, 43% is not quite low enough imo esp in auto downhill.

[Ben-e-boy]

Also I noticed on patrol4x4 Marks are also doing 63% reduction gears. They have a group buy going atm. Would be the reduction I would get, 43% is not quite low enough imo esp in auto downhill.

My mate has a 5L 80 series stock geared, he has great engine breaking, 43% is slightly lower than that, you'll be surprised

[jay see]

My mate has a 5L 80 series stock geared, he has great engine breaking, 43% is slightly lower than that, you'll be surprised

If I can get the patrol going down hills at half the speed without touching the brakes I'll be happy with that.

43% reduction is close enough to half.

[Agronaught]

I'm also thinking of doing this ahead of a front locker install as it would provide more control during decents and over obstacles.

I found the combination of larger tyres (33) on the manual tb48 to be a little to quick in low 1st.

Just to confirm this shouldn't impact high range performance at all, right?

[jay see]

I'm also thinking of doing this ahead of a front locker install as it would provide more control during decents and over obstacles.

I found the combination of larger tyres (33) on the manual tb48 to be a little to quick in low 1st.

Just to confirm this shouldn't impact high range performance at all, right?

High 4, no. The gears are for low range they go in the transfer case.
If I'm wrong someone will correct me.

[Cuppa]

If only after greater control during descents here is another possibility http://www.nissanpatrol.com.au/forums/showthread.php?28582-Exhaust-brake-for-4-2&highlight=exhaust+brake but it won’t give the climbing ability at idle like in Ben-e-boy’s video.

I ended up putting it all on the back burner & will re-visit greater downhill control if & when I find I need it.

[FNQGU]

My mate has a 5L 80 series stock geared, he has great engine breaking, 43% is slightly lower than that, you'll be surprised

Yeah, I've got the 43% reduction with the Auto and Manual Lockup and it works well on the downhill steep descents for the general 4wdriving that i find myself doing. At some stages I have found myself wanting a lower gear again (one section on the Creb Track and some rock drop-offs at Maytown), but it is only on a few rare occasions, and to put it in would only compromise the rest of my off-roading in low range. I'd be interested in trying that 63% reduction, but the 85% would be too much for my needs.