Aisin hubs breaking off, Rockcrawler gear

[arby92]

Gidday Gents,

I am not the most regular poster here but do a fair bit of 4wding with some mates in the background.

I have a reoccuring problem, I have Aisin manual locking hubs on my front solid axle toyota lancruiser diff, it has a lockrite locker in it (the diff is not in a landcruiser). When I am in a sticky situation and put the truck into low gear (rock crawler gears), give her some s&*t if the truck bounces around the wrong way and the front gets a little bit airbourne on one side it is almost garunteed when it lands the hub blows off breaking all six studs clean in half. While this is not difficult to fix, easy out them out and put new ones in. Cone washers get continuosly harder to find and the two little locating pins are starting to wear through the actual hub but more than that it is a nuisance. The hubs themselves are magic and never have any issues, so two questions:

Does anyone else have these problems?
Is there any way I can make this fixing point stronger? or am I just generally doing something wrong?

Second reoccuring problem is I used to have rockcrawler gears in my transfer case and it used to jam up when trying to pull it out of low 4wd, the truck was never running at the time and it seemed to lock into neutral and not go anywhere. Anyway one day the transfer case died so now I have Marlin Rockcrawler gears in my transfer case and have had a complete rebuild at the same time done by myself and my father who is a engineer. The problem hasn't occured for ages but over the weekend it happened once (not a lot) but is bloody annoying because you have to take the shifter off and get the crowbar in there to pop it back in gear, re gasket the top bolt it on before you can continue. It only seems to be in certain situations when it does it and I am wondering if it is something to do with drivetrain bind? and is there any way I can alleviate at this?

[DJ]

and it seemed to lock into neutral and not go anywhere

Hi
Although you havent said what type of gearbox you have, I have had the same problems with a surf w56 gearbox and traced the problem to the nylon bush in the gearbox top plate where the gear stick is mounted. To check if there is any wear ,try lifting the gear stick without undoing any bolts etc . If you can get play then start by replacing the bush.
just my 2cents worth
cheers

[Swamped]

sj zuks do that when the transfer bush gives out. gets stuck in neutral.
Never destroyed hubs like that. Does the little gear thing slop around insided the hub housing to give it enough room to break the whole thing?? Maybe the hubs over torqued?? Use better bolts and torque correctly??
If it fixes the problem it may move the damage to the next weakest component however.
I'm just guessing here.....

[turoa]

sticki 10mm studs and dowels in and that should stop em breaking off

[oldblue]

Did this Toyota Diff have electric hubs and are you useing spacers to fit manual hubs ?

[kbushnz]

Make sure the dowl pins are installed.
The studs will shear under load.
But having said this your hubs are now a fuse in the system.
Better some studs that a CV or diff.

Calvin

[arby92]

Jees didn't expect that many responses that quickly. Thanks guys

DJ - I am pretty sure it is a surf box the toyota part number is something like RFA1, it is a gear driven front shifter where the forks come out the front and are housed in a marks adaptor. The actual shift lever has a fair amount of slop in it but the forks have virtually none but from memory when rebuilding the box the shift forks didnt have any nylon bushes just two holes drilled through the casing in the front of the box where they come through to the adaptor. Maybe extending the little tab on the bottom of the shift lever that engages the forks would stop it from slipping out?

Not sure if the diff was originally electric hubs no spacers from what I can see. I had 8.8 manifold studs in there same as original sourced from a local engineering shop but I might try some 10.8 Allen cap screws sticking with the original 8mm diameter. If I rotate the hub 180 degrees and redrill the dowel holes in the actual diff casing it matches to will I encounter any other issues?

Thanks

[kbushnz]

Is there 1 dowel or two.
All the cruiser hubs I have seen use two, opposite each other.



Cheers
Calvin

[arby92]

There is two opposite each other, on the last breakage one has dissapeared from the hub. I am getting a new on put in. The actual face on the diff where the hub mates too (not sure what this is called) looks a little worse for wear where it has slipped. It looks as if it could be rotated 180 degrees and have the dowels redrilled without causing any issue

[oldblue]

If you move 180 degrees you'll be no better off, try 60 or 120 degrees