Outer Limits 4x4 Board

so i may be able to get some vitara diff gears (5.12:1 i think) will these fit, i heard rumours that they do but just want to see what the go is. has anyone done this before?

yes the 5.12's fit into the Sierra but you need 2 front diffs & it would be wise to get the R&P swapped into the steel carrier as the Vitara one is alloy & is fragile.

is it worth the hassle?? i am currently running 31 and want a bit more performance. saving for transfer gears, but can get hold of these cheap

put them in the cast sierra centres and they will be bullet proof.(and very very quiete!)

look carefully at the real cost. I've seen plenty of people (including myself) set up gears in sierrs diffs themselves and get it wrong, resulting on poor life, noise, and broken gears.

Professional setup on gears isn't all that cheap, especially if your diff guy recommends bearing replacement or other repair work.

Also bear in mind that lots of vitara front gears are 1/2 rusty from never being run in 4WD.

5.12's are great in some circumstances, however, unless you are planning very large tyres, you'll have far too much gearing for road use once you have transfer gears.

Additionally, 5.12's don't provide sufficient low range gearing (only 45:1 crawl) to make the expense of setup worthwhile IMHO.

Just some thoughts. I run 5.12's (and transfer gears) and I found the cost of 5.12's, installed, pretty similar to the cost of transfer gears.

I'll install my own transfer gears but I won't do diffs - I've seen too many go wrong.

Steve.

i got my 5.12s installed by joe and would recommend them everyday of the week
never had a problem with them and plenty of gearing for most 4wding
sometimes too slow for mud and hills but thats what second and third is for lol

Wideaz, you do run 33's though.

Steve.

I know I run toys but I have 4.8 diff gears and combined with 6.5 t/c gears and 35s its just bearable around town and on short trips.
The 20min trip to work everyday was driving me crazy 4000rpm and slow as!
So at the moment Im running stock t/c 4.8 diffs and 35s and its good on road (with the 1600 pushing it) now I actually change gears not put it in 5th and leave it.
But saying that before lower t/c gears were available I did run 4.6 vit diff gears and 4.16 t/c, but as gwagen said to "do it properly" (I had to pay $500 to get just one r&p changed with new bearings) its not any cheaper than t/c gears that will give you great off road and decent on road to.
If its a d/d get on a gear calculator and have a play to see what rpm/speed you will be doing.
If you do do it at the very least use a seirra steel carrier in the rear I ran the alloy front in the front on 32s and was ok depends how hard you drive.
Just my experience
Nik

Gwagensteve wrote:look carefully at the real cost. I've seen plenty of people (including myself) set up gears in sierrs diffs themselves and get it wrong, resulting on poor life, noise, and broken gears.

same applies to t/case gears, though you have a better chance of getting diff gears quiet.

Gwagensteve wrote:Professional setup on gears isn't all that cheap, especially if your diff guy recommends bearing replacement or other repair work.

Also bear in mind that lots of vitara front gears are 1/2 rusty from never being run in 4WD.

it is cheap if you take it to the right specialists. vitara front gears rust from never being used? never come across one yet. i have however seen some rusty ones that HAVE been used is 4x4 and seen water, or been in a fire. (and not from my supplier.)

Gwagensteve wrote:5.12's are great in some circumstances, however, unless you are planning very large tyres, you'll have far too much gearing for road use once you have transfer gears.

Additionally, 5.12's don't provide sufficient low range gearing (only 45:1 crawl) to make the expense of setup worthwhile IMHO.

whether you run 31's or 33's they will be fine. i aim for a rev range between 3600 and 4000 rpm, anything below 3500 will just chew through more juice, have less on tap power and make everything work harder (torque wise). 5.12's are adequate with 33's, over that may be a problem but its hard enough for me to engineer 31's (yes i get them legal) let alone trying to put anything on the road that can run above 33's. i am yet to have a customer or a friend come back to me saying they have not enough low range, there has been no noise issues and i have only had a set in a vehicle brak because the customer got it airborne, and thats one set out of a bucket load. but at the end of the day everyone likes there own thing.

This is no attempt to turn this into a transfer vs diff gear thread, but I will relate my experience- as I pointed out I run 5.12's in my car and consider them an important part of my car's gearing.

I have encountered rusty 5.12 gears, and I have seen lots of 5.12's that were never set up properly and were unusable or broke. I even bought 2 sets that had been victim to a "home" gear setup that I had to throw away.

All 5.12 diff gears will be second hand, and that comes with risks, and not everyone that says "sierra diffs are easy to set up" knows how to do it - but you'll only find that out two years later when they're worn out or you go to fit a locker and the diff guy tells you he has to throw out your 5.12's because he can't get a pattern on them.

you'd normally budget about $250 per end for a gear swap, drive in, drive out, plus the cost of the gears. It's generally a $1K job all up. That's without using it as an opportunity to add or upgrade a locker.

That's about the same price as transfer gears, but delivers nowhere near the spread of gearing.

I'll stand by my position that sierras need about 60:1 crawl ratio to be easy to drive in steep terrain with lockers, and everyone I know that had 60:1 now has more and/or an auto and has never looked back.

IMHO, diff gears are useful for correcting tyre size on road, but they do nothing to resolve the fact that sierras geared too tall off road.

The fact is a sierra with 31's and 5.12's as the only form of gearing correction is spinning at 4100rpm at 100 km/h, but only has about 10% better gearing off road than a standard sierra. That's poor use of $1k in my book, when the same car with transfer gears can be geared close to stock at 100km/h and have almost double the low range of the 5.12 car for the same money.

apparently transfer gears break - but I've thrown away more $ in 5.12s than I have transfer gears.

Steve.

if your doing normal track 4wding wheres theres mud hills rocks and ruts wouldnt 6.5 transfer gears be way to slow for all of that bar the rocks??????

ive only ever needed 1st low for down hills and rocks drop ins

most of my 4wding is mud ruts and up hills where i need momentum 6.5 would be way too slow for any of that...........

wideaz wrote:if your doing normal track 4wding wheres theres mud hills rocks and ruts wouldnt 6.5 transfer gears be way to slow for all of that bar the rocks??????

ive only ever needed 1st low for down hills and rocks drop ins

most of my 4wding is mud ruts and up hills where i need momentum 6.5 would be way too slow for any of that...........

You do realise you can use your gearbox in 4 wheel drive don't you?
Peter.

often situations where momentum is an issue offroad means a locker of sorts will help far more than momentum... unless you're in mud - then its all right foot =) haha

i don't know what your all yelling about but I'm now angry too...



wideas i don't know if you run 6.5s or not but i did and they suck on everything else then on the rocks. In low you just can't get enuff momentum to rock over things or to pop that slippery rut. apart from section on where i had to crawl i was in high range idling along...

You need to set your truck up for what you drive, and how you drive. JMO

Absolutely 31Zook.

I run mud in 4th low, and my motor is rev limited at 7500rpm, so that gives me 35km/h in 4th gear low range, on the rev limiter. If I need more than 35 km/h of wheel speed, I don't need to be in low range.

If I had a motor with a lower rev limit, I wouldn't run 5.12 diffs, but I wouldn't give up my 6.5 transfer gears.

I'm barely ever driving rock, and I barely ever use 1st low.

Steve.

31zook wrote:i don't know what your all yelling about but I'm now angry too...



wideas i don't know if you run 6.5s or not but i did and they suck on everything else then on the rocks. In low you just can't get enuff momentum to rock over things or to pop that slippery rut. apart from section on where i had to crawl i was in high range idling along...

You need to set your truck up for what you drive, and how you drive. JMO

Like Pete said, use the other 4 gears you have?

Mock

i wouldnt suggest going up a near verticle hill in 4th boys lol

wideaz wrote:i wouldnt suggest going up a near verticle hill in 4th boys lol

Why not

Mock

What do you mean wideaz?

My 4th low is 25% lower than a standard sierra's 1st low. I'll pick any available gear that has the right balance of torque at the wheels and momentum.

Steve.

wideaz wrote:i wouldn't suggest going up a near vertical hill in 4th boys lol

Ever heard the saying sometimes it is better to keep you mouth shut and be thought a fool than open it and prove you are one ... this is one of those times ...

The guys your trying to impress know how to drive and have quite a bit of experience in the bush.

what ever mate!!!!


here we go again, outer limits acting like wankers

im just saying a near verticle hill where you need momentum speed and traction starting for a start stop i dont think ull be using 4th


thats all i was saying

wideaz wrote:what ever mate!!!!


here we go again, outer limits acting like wankers

im just saying a near verticle hill where you need momentum speed and traction starting for a start stop i dont think ull be using 4th


thats all i was saying

No!
Calm down, nobody is wanking yet

So you wouldn't use 4th in your car, fair enough. I wouldn't use 4th in mine either; but some of these blokes who have commented in this thread have so much gearing in their cars that 4th low is probably a sensible choice.

I am not wanking one way or the other but isn't 4th the strongest gear in the box?
Peter.

AFAIK yes, 4th is the strongest gear in the box.

Wideaz, I think you are misunderstanding something about gearing.

I'm obviously a wanker, but I still don't know what you're on about wideaz. As for what gear I'd use on a "near vertical" hill, it would depend on the surface condition, the length of the climb, and the weather. If it's short and dry, I might use 1st low, and crawl it. If it's loose and dry, I might use 2nd low. If it gets longer and more slippery, I'll use taller gears to carry momentum. That will quite often leave me in 4th low, which in my case, always seems to provide me with enough momentum.

Whilst being a wanker, I've explained that my 4th low is a bit lower than 1st low in a stock sierra, (but I have much taller tyres, which gear the road speed up) so when a stock sierra is using 1st low, I really might choose to use 4th low.

In fact, my 1st HIGH is lower than a standard sierra's 1st LOW.

I don't care what combination of gears I use, so long as it gets the right result - so I'll use 4th low a lot when I'm on hills. Once I'm in 4th low though, I am in the "overlap" with high range. If 4th low isn't fast enough, or the climb is really long, I won't labour along in 4th low at high revs, I'll be in 1st or second high. However, if there's a ledge, ruts or other point that means I'm going to need to slow right down, I won't start the climb in high range as 1st high won't give me enough torque to pull away if I need to slow to a near stop, and it might not be safe or desirable to stop the car and engage low range.

I almost never use 4H though - in my case it seems that if I need the speed of high range I don't need the traction of 4WD.

PS I won't ever use 5th low, as the 5th gear idler is very small and isn't designed for high load, and jackshaft speed becomes excessive at high revs in 5th low.

I hope this helps you understand why I can't see the problem with 4th low.

Steve.

im the same as steve.... pretty much use exclusively low range offroad, and if im hopping between tricky sections on some just averge dirt roads ill chuck in to 4H or 2H... generally 2H cos i get to do skiddies =)

i frequently use 1,2,3,4 and 5 low... although 5 low is on a short gap between sections - so ill rev around 2500rpm and cruise in 5th to the next bit rather than stopping to change to high range and stopping further up to go back to low.

I've never used 4th or 5th on a hill climb in low, prefer 2nd/3rd and more revs if i need wheel speed - its way more controllable to just take the foot off the accelerator and let the gearing slow me down rather than jabbing the brakes.

WOW

all i can say is wow

i never new low range all 5 gears was worth using
i only use low range if i need it and ive never used all 5 gears if i did i would just use 4h 1 or 2 gear

all your gearing must be so slow, that i want me some now cause im not using my 5 gears in low at all
ill look into some 6.5s or higher
thanks everyone

PS i didnt mean u steve was a wanker i respect ur comments highly

You'll normally find that the "overlap" point is around low 3rd/ high first.

That said, you don't want to be driving up something in high first and "on the edge" of holding the gear, because then you can't change down into a lower gear.

Steve.

my overlap "take off" gear is 3rd low... ie: can come off the clutch 'normally' and take off no worries - however the 3rd low runs out of acceleration and just revs way sooner than 1st high... 1st high will net me about 30km/hr doing average-high revvs (guessing), 3rd low will have me redlining for that 30km/hr for sure... as 5th low's max speed for me is 45km/hr pushing about 5000rpm.

my gearing is calmini 5.14 tcase and 31's.

so guys any idea's where i can get some vitara diff gears cheap?

as my bro is a mechanic so gearing install and set up is gonna be a "FREEBIE"