Will my transfer case reduction gears destroy my front diff spider gears?

[Tanya]

Hello Forum

I just spent the weekend installing Marks 85% in my GU. Then my brother on law who just had his JK wrangler diff ratios reduced to run 35s tells me he shredded his front diff spider gears on the weekend.

I haven't done a front locker yet, so now Im thinking that before I go out and put my new gears through their paces, maybe I should do the locker first?

Or will my GU front diff spider gears be able to handle the extra force, unlike my brother in laws Jeep.

What does everyone else think? Is it worth a locker or will they survive without it?

[MB]

G'day Tanya, although your Patrol diffs are heaps tougher than a Jeeps if you're planning on fitting lockers anyway then best to do now I believe. Just remember too that once front lockers go in the force on your hubs is far greater than before. I've strengthened my hubs with these below for peace of mind out there for under $30 !
http://patrolapart.com.au/product/ni...ub-saver-rings

[Tanya]

Thank you for your reply MB

I have already replaced my auto hubs with manual including strengthened rings, however they are a bargain at $30, will definitely be adding that link to my favs.

I am almost convinced it is worth reducing my savings account so soon to purchasing the gears, however I didn't want to spend the dosh now, only to find out that my hubs and cv's will go well before the diff anyway.

[PeeBee]

Tania, couple of comments1) the 85% reduction gears will give you a torque increase on the output shaft of the transfer cases which in turn is transferred to the wheels by the diff, however you are also going slower for the same rpm. By definition then if nothing gives the spider gears will see that torque increase, and if the obstacle they are traversing puts a higher load back on the gears than they are rated for they will be damaged. I am assuming the standard GU front diff has 2 spider gears, so if you install an ARB locker you get upgraded to 4 spider gears so the load is halved on the gears - but - if they are engaged then nothing in the system is able to handle the excessive resistance if you drive it in really tough conditions, so the spider gears and everything in the system will see the higher loads,(uni's, cv's, axles, wheel nuts/studs etc) and as @MB suggests, the result would be a breakage in the weakest component. 2) I don't know if the hubs will go before the spider gears, dont have the capacity ratings, but I run twin lockers, 85% reduction gears, hub strengthener rings and a have a ChevDiesel V8 behind it and have not broken anything, however I don't drive it hard either.
Just my thoughts.

[Tanya]

Thank you PeeBee for adding your thoughts, it is greatly appreciated.

Seeing as your twin locked and are yet to break anything, as well as MB's recommendations to do it now if I was going to do it anyway, I have decided to bite the bullet and do the front locker now.

Thanks for both your contributions, and for helping me make my mind up.

[PeeBee]

What engine are you running Tania and is it Auto or manual?

[Tanya]

Just a little 3l, and auto.

[mudski]

Personally I think you will be fine, even without the locker. I have never heard of a Patrol destroying spider gears from having reduction gears. But there is s a first time for everything they say. What made you go 85% too? Thats a big difference. Maybe being auto has something to do with it.