[kd883]

Hi guys,

Looking at buying some 4.9:1 reduction gears for the transfer case. Have been told the mounts need to be beefed up, maybe even need to fit a roktoy ring.

How essential is this? What are the options?

Cheers,

KD.

[Bruce]

Get these T/case mounts. Bullet prof.
viewtopic.php?f=15&t=15518

[kd883]

Thanks for that Bruce.

I don't quite understand the need for the strengthened mounts though - do the reduction gears strain the case or do they just make it move within the mounts more?

Is it essential to lift the transfer case? Or is it just a wise thing to do? Does this affect any other gemoetry within the Sierra?

Cheers.

KD.

[jdk81]

A roctoy ring is a bit of safety,

I would advise against "beefing" up transfer case mounts. The stock ones function correctly in the majority of situations.

Ive wheeled with 6.5s on a xfer case with no roctoy ring, and stock mounts.
No breakages so far, although I did bend the long arm on the transfer case.

Besides which, not a lot has changed in the world of suzukis since you were told this info a week or so ago.
viewtopic.php?f=5&t=30837&p=564078#p564078

[atari4x4]

buy these Sierra Transfer Case Mounting Arms http://www.auszookers.com/forum/viewtop ... 15&t=15009

[kd883]

jdk - why do you advise against 'beefing' up mounts?

Why do reduction gears stress the mounts? Is it because the whole unit moves more under increased torque?

[SierraDan]

I beefed up my long arm mount cos they twist and bend and run standard rubber mounts with 5.14's, G13BA and 31's. i recently broke a rubber mount, so poly ones are on the cards.
Roctoy ring and super mounting would suit 6.5's and big tyres better but still no reason not to have one, good safety

[kd883]

Please forgive me guys but what is a long arm?

[atari4x4]

the opposite of short arm...

there are 2 "arms" that hold the xfer case, one is long the other is short.

[SierraDan]

There are two mounts attached to the transfer. one is long with two rubber mounts that attach to the chassis one is short with one rubber mount to the chassis.

Just bits of metal holding it in place. You'll know when you see it what we mean.

[Zook_Fan]

The driver side mount is an arm that has two mounts on it. Commonly referred to as the long arm as the other side is smaller and has only 1 mounting point

[kd883]

Ah huh! Thanks guys.

So would poly mounts for the long arm (and short arm as well I guess?) be enough to support 4.9:1 and 31's? It sounds like the roctoy ring is only really designed for tyres and reductions bigger than this?

[Zook_Fan]

Poly mounts help keep the mounts together. The roctoy ring helps keep the alloy case in one piece. They are for two completely different purposes that are both affected by gearing. You could get away with stock stuff or you could insure your gears stay where they should be and spend the extra money. Up to you

[jdk81]

Precisely, the xfer could use some extra support, as it is now generating extra torque. (torque = power/angular velocity). You dont have to provide the extra support, but its worth considering.
A big part of how much you break depends on how you drive.

The long arm is the long bracket which bolts onto the xfer case. This is then bolted to the rubber mounts and onto the factory location.
Bracing up the brackets which bolt on the xfer case (using a roctoy ring, and/or custom brackets etc) assists in reducing chances of xfer case damage. As these brackets are stronger and have more bolting locations to the alloy housing of the transfer case.

The mounts Bruce linked "upgrade" the factory rubber mounts, which removes the designed mode of failure, and places it somewhere else.

I detest this method of upgrading things, as you will make something else harder to fix, break. Its easy to change a replacement rubber mount, things are engineered this way for a reason.
Its hard to weld the chassis mounts without a welder in the bush.

Some people like solid mounts, it works for them. Thats great, I advise keeping an engineered weakpoint in the system.

[Zook_Fan]

I agree with the above philosophy. Leave the weak link in place and build the strong parts stronger. Rubber mounts are suppose to be disposable, transfer cases are not.

[SierraDan]

4.9 would be fine with standard or poly mounts.
But you will want stronger long and short arms. or they will twist.

I drive VERY hard and over a year later i finally rip a rubber mount in half.

[Bruce]

I've been running the poly mounts for 3 years now in my Comp Sierra and they are great.
I run 5:14:1 gears.

[kd883]

Thanks very much for all the input fellas. Sounds like keeping the standard rubber mounts (and a couple spares in the glovebox) would be the go, with stronger brackets.

So what are the pros and cons of reduction gears within the diff's rather than the transfer case then?

Cheers.

KD.

[SierraDan]

I keep spare mounts. Took a couple of minutes to swap.

lower high range aswell as low and taking some of the load of the reduction somewhere else in conjunction with transfer gearing.

[kd883]

Ah! Good to hear the mounts are a quick and easy change over. Cheers SierraDan.

I am primarily after high range reduction, as my Sierra is my daily driver. Highway driving is painful at the moment!

Would diff or transfer reduction be better for this? I could probably only afford one or the other at the moment.

Cheers,

KD.

[kd883]

Ah! Good to hear the mounts are a quick and easy change over. Cheers SierraDan.

I am primarily after high range reduction, as my Sierra is my daily driver. Highway driving is painful at the moment!

Would diff or transfer reduction be better for this? I could probably only afford one or the other at the moment.

Cheers,

KD.

[SierraDan]

It will help with highway driving significantly. both diff and transfer gears will help. but a combo is best.

I'd go transfer first.

[jdk81]

Diff gears reduce the stress on the driveline.
Diff gears can correct the speedo
Diff gears affect high and low range equally.
Diff gears may be a requirement for engineering, and correct speedo is a requirement.

Transfer gears generally appear cheaper (cost is about the same), and give a better spread of gears between high and low.
With the option of getting high range back to standard whilst allowing crawling in low.

Once again, to repeat what I said the other day
I would prefer 4.6 diff gears with 4.16 xfer gears.
I currently have 3.7 diff gears, and 6.5s. I dont see enough rock to use low 1st. Im pretty sick of changing between high/low on the trails.
low range is limited in the sand.
Even on tyres 33" diam, low 1st is still too low.
On 31s, im in low 3rd most of the time.

I feel 6.5 is too low imo for a balanced type car (trying to set up for zook touring, doing bits of everything).
Which is why I would prefer 4.6 diff gears and 4.16xfer (with sierra gear box).
If I change gearboxes I might go different diff ratios again.

My car is also a daily driver.

Just because one option is cheap, doesnt mean its right for you.
Buying something that isnt quite right by justifying saving a little bit money, brings big regrets.

[kd883]

Thank you very much gentlemen.

[rpmwrx]

I posted this in another thread a few weeks ago, but i feel it's relevant to this thread also...

I read this article on trail tough website the other day. Very interesting read...

I am running the 4.16 transfercase gears and 5.1 diff gears on 33's and for vic conditions it is a good combo...


Question - Transfer case gears or axle gears?
While doing Suzuki Samurai transfer case gears is probably the biggest bang for the buck and a quick-fix, it is definitely a lousy way to try and create a reliable, trouble-free drivetrain. So think about this for a minute...you put on larger tires, so your pinion now becomes TWICE as hard to turn putting TWICE as much stress on the u-joints, transfer case mounts and the transfer case itself, as well as the brackets on the side of the frame that holds the transfer case in place. It leads to problem chasing such as having to use unnecessary large and heavy driveshafts, having the bolts pull out of the transfer case on the long arm side, having the mounting boss break off of the transfer case or having the short arm side bracket start to tear off of the frame rail. It is because you have given your transfer case up to 3 times as much power by putting in lower gears and now the transfer case wants to do flip-flops in its mount. Many people consider only the POWER issue of this equation as opposed to considering the STRESS LOADING situation as well. You need to change the ring and pinion gears also - relative to your tire size - which will make the driveshaft easy to turn again, taking all of the strain off of these parts - just like it was made from the factory when the smaller tires were on it. It is a mistake to do all of your gear reduction at one point. Especially that far up the mechanical chain. Do yourself a favor....reduce the ratio at the ring and pinions relative to the size tire you want to run, then select the transfer case gears that will best meet your 4-wheeling needs. By going this route, you will have a well thought out and trouble-free drivetrain, working well within the parameters of strain that the parts can and will reliably handle.

Something to think about anyways...

[suzukikid]

beef em up! i had 4.9's in my old sierra....was bending mounts left right and center.....beefed up the long mount and it was spot on never had a drama....

in this one with 6.5s i got roctoy ring, beefed up mounts, lifted it 50mm....

better to be safe!

[burls]

I just dug this up in my afternoon of leisure reading

What would be the optimum diff gears when running 33'' and 4.9 gears

The vehicle is going to be mostly used off road

[jdk81]

burls wrote:

I just dug this up in my afternoon of leisure reading
A0
What would be the optimum diff gears when running 33'' and 4.9 gears

The vehicle is going to be mostly used off road

Assuming sierra gearbox

Id consider 4.3 diff gears
Approx 3550 rpm at 100 km/h
low 1st is approx 77:1 (however sometimes you may be wanting here, but in general I think the 4.9 and 4.3 diff gears is a nice spread of gears).

[burls]

Sorry forgot about the gearbox
Mines a vit gearbox sierra transfer
Sierra diffs

[pezz]

4.3 or 4.6 I recon