Slight vibration

[dom14]

After driving the vehicle today, I realized that the vibrations were mostly felt at high revs. They seemed to have been getting worse. anyway, checked underneath this evening. Found that the bolts connecting the driveshaft to the rear diff were loose enough to be turned by hand. Going to tighten them up in a while.

What?!! That's not good news. Those bolts need to be torqued properly or else the uni joint & diff pinion won't be happy.
Sounds like you've found your problem, but might have done the damage already anyway.

After tightening the bolts, park the vehicle without handbrake on and feel if there's any up/down/side movement in the uni joint(even better when the rear wheels are jacked up)
or diff pinion/yoke. There shouldn't be any movements at all. If there IS, get the uni joint or diff pinion bearing done accordingly.

[dom14]

Check that one or both your front hubs are not locked. I can get a very similar and slight vibe if i am still running in 4wd even when i 2wd

You didn't mean auto hubs, did you?

Following the advice from the blokes here while ago, I lock the hubs once every few weeks and do few good miles to "lube" them by breaking the extended stationary position of the front axles, cv, diff, etc.

While the petrol tank work was getting done and fixing some carby issues(removed the rear driveshaft), I was driving on the 2WD front wheels on very short trips for few days.
There was bit more vibration and grunting than normal, but it wasn't that bad as long as I stick with speeds upto 60km/h, but not any faster.

[MudRunnerTD]

You didn't mean auto hubs, did you?

Following the advice from the blokes here while ago, I lock the hubs once every few weeks and do few good miles to "lube" them by breaking the extended stationary position of the front axles, cv, diff, etc.

While the petrol tank work was getting done and fixing some carby issues(removed the rear driveshaft), I was driving on the 2WD front wheels on very short trips for few days.
There was bit more vibration and grunting than normal, but it wasn't that bad as long as I stick with speeds upto 60km/h, but not any faster.

Yeah I've had a vibe issue in my GQ and GU for this reason. The GQ I had not unlocked the manual hubs and in the GU with Auto hubs set to Auto I had not disengaged them properly and the front shaft was spinning.

[dom14]

Yeah I've had a vibe issue in my GQ and GU for this reason. The GQ I had not unlocked the manual hubs and in the GU with Auto hubs set to Auto I had not disengaged them properly and the front shaft was spinning.

If we leave GU auto hubs on "free" position, then we shouldn't have that problem?
But, that means it's essentially used as a manual hub, isn't it?

[MudRunnerTD]

If we leave GU auto hubs on "free" position, then we shouldn't have that problem?
But, that means it's essentially used as a manual hub, isn't it?

The Auto Hub only has Auto and Lock. So when using in Auto mode and flicking back to 2wd it's essential to put the car in reverse and reverse to disengage or you can drive forever with the front driveshaft still engaged.

[dom14]

The Auto Hub only has Auto and Lock. So when using in Auto mode and flicking back to 2wd it's essential to put the car in reverse and reverse to disengage or you can drive forever with the front driveshaft still engaged.

Probably you don't wanna do that to preserve the lifespan of the transfer box, you reckon?

BTW, auto hubs not having a manual choice obviously explains why some blokes convert them back to manual.

When auto hubs don't work properly and stays locked, it's a problem, isn't it?!

[Lawrence]

Check that one or both your front hubs are not locked. I can get a very similar and slight vibe if i am still running in 4wd even when i 2wd

Thanks Mudrunner.

[MudRunnerTD]

Probably you don't wanna do that to preserve the lifespan of the transfer box, you reckon?

BTW, auto hubs not having a manual choice obviously explains why some blokes convert them back to manual.

When auto hubs don't work properly and stays locked, it's a problem, isn't it?!

Yeah driving on the bitumen with the front locked in puts stress on your CVs and Diff centre so its not ideal.

The Auto Hubs kind of act the same as an Auto Locker in that they engage when they sense drive, the reason guys change them or modify them to be Lock and Unlock is they can Drop Out rather than Lock up. Pain in the arse really, when they fail they just drop out and you loose your 4wd option and drive to the front. They also tend to drop out in Reverse. By choosing the Lock position they tend to stay in and should be bedded better but fundamentally they are weaker than a standard manual hub and given a choice the manuals are the go.

Autos are awesome for switching on the Fly. I can choose Hi Range 4wd on a dirt road at 60kms/h and visa versa. but to disengage them you really need to stop and reverse up 5m to 10m to click them out.

[dom14]

Yeah driving on the bitumen with the front locked in puts stress on your CVs and Diff centre so its not ideal.

The Auto Hubs kind of act the same as an Auto Locker in that they engage when they sense drive, the reason guys change them or modify them to be Lock and Unlock is they can Drop Out rather than Lock up. Pain in the arse really, when they fail they just drop out and you loose your 4wd option and drive to the front. They also tend to drop out in Reverse. By choosing the Lock position they tend to stay in and should be bedded better but fundamentally they are weaker than a standard manual hub and given a choice the manuals are the go.

Autos are awesome for switching on the Fly. I can choose Hi Range 4wd on a dirt road at 60kms/h and visa versa. but to disengage them you really need to stop and reverse up 5m to 10m to click them out.

I used to drive an old Jackaroo & the auto hubs were working fine for an old vehicle(83 model I think).
I've never had to reverse to release the auto hubs.
I wonder why these newer patrols couldn't come up with an auto hub like that.
Manual hubs are reliable, but bit of a PITA when you have to get out to engage them all the time, depending on the frequency &
the spot that I need to get out of the vehicle.