GU Hubs (again)

Submitted: Friday, Oct 17, 2003 at 09:18
ThreadID: 7882 Views:2191 Replies:4 FollowUps:10
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Hi,
Can't seem to find a definitive answer to this question, hoping someone out there might know:

When in 4wd, will the hubs (in auto mode) disengage if reversing?

My understanding is that the hubs lock when drive is applied to them, that is why the owners manual says avoid high revs takeoffs when in 4wd - the hubs may make a grinding noise (trying to lock), which can't be good.

So, if you are in 4wd and reversing, there is still load being applied to the hub, so why would it disengage? (I understand that when in auto mode there is a chance they can disengage when on and off the throttle etc - just like you can push the gear stick out of gear in the same situation)
Thanks.

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Reply By: Mick - Friday, Oct 17, 2003 at 09:32

Friday, Oct 17, 2003 at 09:32
Yes they do "sometimes" disengage when driving in reverse.
We have smashed several sets or the automatic hubs, on our off road truck we took in the tuff truck challenge, due to reversing to take a runoff, and then giving it heaps.
If they are locked they wont disengage in reverse and youll have no problems.
If you are giving your truck curry in 4wd, make sure you lock them, as many other people in these challenges have broken them by not locking them in.
A simple fix is to put the manuel locking hubs on from GU utes, or GQ ones will also fit which are easy to find.
AnswerID: 34128

Follow Up By: GUPatrol - Friday, Oct 17, 2003 at 09:40

Friday, Oct 17, 2003 at 09:40
Mick,
I have done some research and apparently not all the GQ ones fit the GUs...
They reckon the shaft is thicker on the GU??
Are the AVM ones strong enough?
I had a look at a set and it looked kind of crapy...
Will
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FollowupID: 24549

Follow Up By: Mick - Friday, Oct 17, 2003 at 10:22

Friday, Oct 17, 2003 at 10:22
Whos "they", and they reckon wrong, the axle splines and shaft diameter are the same.
All GQ's have the same front diffs, the GU's upgraded to a fatter CV joint, and diff width is about 1" wider, but the splines are the same, and this is why the GQ hubs fit.
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FollowupID: 24556

Follow Up By: GUPatrol - Friday, Oct 17, 2003 at 10:32

Friday, Oct 17, 2003 at 10:32
Mick
"they" is wreckers... and I think they are wrong as the AVM part number is the same right across the range.
I just called one wrecker who has got a set $165 each side!!
AVM hubs are only $140 for both sides....!

Will
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FollowupID: 24557

Follow Up By: Truckster (Vic) - Friday, Oct 17, 2003 at 13:32

Friday, Oct 17, 2003 at 13:32
AVM, head of lots of them exploding.... Not better...

YMMV.
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FollowupID: 24582

Follow Up By: Mick - Wednesday, Oct 22, 2003 at 07:54

Wednesday, Oct 22, 2003 at 07:54
Sorry, we wreck our own patrols, and have parts laying everywhere!
We are sponsored by Bouncer spares as well for our tuff truck, so most of the time parts cost nothing. We picked up our complete GU diffs, front and rear for $900! some people have paid $2000 each!
We threw some old hubs off a GQ that were laying around, and havent broken them yet!
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FollowupID: 25034

Follow Up By: Truckster (Vic) - Wednesday, Oct 22, 2003 at 18:39

Wednesday, Oct 22, 2003 at 18:39
So Mick, got any of the vent air direction things off the dash?? And the pipe in the dash on passangers side it connects to?? :)

vfr750fv
at
yahoo
.
com
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FollowupID: 25077

Reply By: GUPatrol - Friday, Oct 17, 2003 at 09:37

Friday, Oct 17, 2003 at 09:37
Baza,
They are actuated by a cam mechanism.
When you select 4wd they lock, if you reverse while in 4wd the cam will go through its process and make a clicking noise however the splines will be under load and the hub does not disengage.
When you bleep f to 2wd the hubs remain engaged until you drive in the opposite direction, then the cam lifts the retainer and since there is no load it releases the slide and it goes back to unlock.
When you lock it with the wheel brace (manual lock posistion) you push the slide in (as in a manual unit) but you also push the cam, so when you go back to auto posistion the hub will stay locked until you drive in the opposite direction.
The cam works at 90 degree rotations and that is why you need to reverse at least a few metres for it to disengage.
They perform OK in normal conditions but in sand and mud (where a wheel may loose tension) they may disengage and immeditely engage again ie: bogged in mud and rocking or when lifting a wheel. When engaging again they may brake but very seldom happens.
I lock mine manually if I am going to do more than one day 4wdriving.
I prefer a manual locking hub and I have been looking at changing mine to AVM hubs...
Will
AnswerID: 34130

Follow Up By: baza - Friday, Oct 17, 2003 at 10:00

Friday, Oct 17, 2003 at 10:00
Thanks Will. That's the explaination I was after.
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FollowupID: 24554

Follow Up By: Lyds - Friday, Oct 17, 2003 at 11:37

Friday, Oct 17, 2003 at 11:37
When you say "opposite direction" do you mean reverse?Cheers,
Stuart
- To err is human, to moo bovine -
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FollowupID: 24558

Follow Up By: GUPatrol - Friday, Oct 17, 2003 at 11:55

Friday, Oct 17, 2003 at 11:55
Opposite direction to what you were travelling, ie:
If you engaged them going forward then it is reverse, if you engage them going backwards, then forward...

Will
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FollowupID: 24566

Follow Up By: american guy - Saturday, Oct 18, 2003 at 13:07

Saturday, Oct 18, 2003 at 13:07
i am not very sure what exactly AVM hubs are but here is my take on the auto hubs quandery.

"RIP THOSE AUTOMATIC PILES OF JUNK OFF. AND GET OUT AND LOCK YOUR HUBS IN"

not to show any disrespect guys, but where i live and what i have worked on everything from manual, auto, auto ford ,auto G.M.
auto dodge, not one of these got it as good and the set up on i have on my toyota 4runner not sure if you guys know what that is it's pretty much the best of all world's, manual hubs no auto crap an c.v. joints.
but if you like those auto hubs there is one thing to consider alot of auto hubs may activate or lock under load my experince with auto hubs and movment on the shaft may partly lock the hub not locking into the splines all the way this will cause a grinding noise the big thing to consider is the outter c.v. joint if that joint binds at all it can cause this concern.
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FollowupID: 24667

Reply By: Mick - Friday, Oct 17, 2003 at 10:17

Friday, Oct 17, 2003 at 10:17
The GQ ones will fit, all the GQ frot, and the GU front have the same axle splines on the outer. The axles are not interchangeable, but the hubs are.
The bolt pattern is the same.
We fitted GQ hubs on our 3.oL GU diff.
No problems.
AnswerID: 34136

Reply By: chrisfrd - Saturday, Oct 18, 2003 at 17:53

Saturday, Oct 18, 2003 at 17:53
Just an afterthought guys...

I took my Nissan GU II hubs off, only due to the fact that I have a really steep sealed driveway that I have to tow a light but fiddly trailer up, so as to get to the transmission towers in Tuggers.

I installed AVM's so as to allow me to engage low 4x4 and have two wheel drive, so as to navigate correctly and stop wind-up.
AnswerID: 34285

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