When 2 diff locks are just enough!

While we're on the topic of cv's, I've been toying with the idea of telling this story since it happened at the beginning of the year.
After 25 yrs of lusting after a Syncro, I finally bought what some forum members would know as "Norbert's Syncro" from Hamish, another member. It ended up having just the specs I wanted with both front & rear diff locks + decoupler. Overkill I was counselled, but the few times I've needed the front diff lock in my 712, 6x6 Pinzgauer, it meant the difference between getting home or not so I was happy! I tidied up a few minor things but despite being concerned by 8 cv's underneath, I thought all was OK, as I couldn't get any warning signs from the usual lock to lock etc tests.
All good so off we went for a 2000km jaunt from FNQ to Brisbane to do the Christmas thing.
On the way home I picked up a friend north of Bunderberg & we headed for Kroombit Tops for a bit of a look. The "Razorback track" to Biloela looked interesting & very suitable to finally try this Syncro out off road, although I hadn't really planned for any serious 4x4 stuff before I'd left home.
Well I was pretty impressed with the way it was handling itself over what was a pretty challenging, if not completely outrageous track. About 10km along a total of 27km we walked nice & easily down a 250-300mm rock step, but it wasn't long after that there was a distinctly ominous noise from the back. We decided that it was definitely from the left rear.
OK, stop & check and sure enough, the left axle is flopping around in the outer cv like the proverabial in a sock.
Oh dear I thought, that's not good......
Best keep going.....
That was ok till we didn't make it up the next decent hill.
After a couple of tries, we realised that only the front wheels were scratching for traction.
Another crawl underneath & sure enough, the other outer was totalled as well.
Oh dear, that's even worse......
Both rear outer cv's totalled in a gulley, 10km along a remote 27km track on a Sunday afternoon, with no hope of going either forward or back despite a few tries, we were in deepish do do!
The first shaft came out before dark & it looked like both cv's were the same.
Amazingly we had mobile reception as we were line of sight with Callide power station in the (far) distance.
A call to PO Hamish confirmed that the cv's were indeed interchangeable.
Well it's a camper so not a totally bad spot to spend the night......
Even got soap & water to help get the moly grease & dust off....
Next morning the other shaft came out & one goodish one made out of the bits & reinstalled.
Tyres let down till good & baggy & away we went.
We decided to keep going the way we were & the track actually got worse, but we managed to drive out with 2 x front & only 1 x rear drive!
I was quite relieved.......
Hamish had been busy & found that the closest chance of replacement CVs was Nth Rocky Mechanicals & indeed they had GKNs on the shelf & put other work on hold to fit them to my axle when I arrived next day.
I can highly recommend them!
The 2 that broke were not GKN by the way. I think there's a lesson to be learnt there?
Sorry this turned into a bit of an epistle, but I hope you got a smile out of it : )

Regards

Jim

Great story Jim.

I had one break on me going up the Waterfall Way near Bellingen. It only failed as the bolts had come loose to the point where 4 of the outer bolts had fallen out (most still sitting in the housing of hub) the remaining two were almost out too when one snapped off ripping the other one off as well which also ripped the joint apart.

A time consuming removal of the offending noisy CV and attached shaft so I only had one rear drive shaft.

I drove 350kms home from there on good roads with the remnants of the shaft in under the seat.

I changed all the CV bolts after that to the multi spline version which can be better tightened.

I also get them regularly checked.

But these vehicles drive well as a 3 wheeler!

Cheers,

Skot

On 11/09/2017 11:26 AM, jim_m@aapt.net.au [Syncro_T3_Australia] wrote:

While we're on the topic of cv's, I've been toying with the idea of telling this story since it happened at the beginning of the year.
After 25 yrs of lusting after a Syncro, I finally bought what some forum members would know as "Norbert's Syncro" from Hamish, another member. It ended up having just the specs I wanted with both front & rear diff locks + decoupler. Overkill I was counselled, but the few times I've needed the front diff lock in my 712, 6x6 Pinzgauer, it meant the difference between getting home or not so I was happy! I tidied up a few minor things but despite being concerned by 8 cv's underneath, I thought all was OK, as I couldn't get any warning signs from the usual lock to lock etc tests.
All good so off we went for a 2000km jaunt from FNQ to Brisbane to do the Christmas thing.
On the way home I picked up a friend north of Bunderberg & we headed for Kroombit Tops for a bit of a look. The &qu ot;Razorback track" to Biloela looked interesting & very suitable to finally try this Syncro out off road, although I hadn't really planned for any serious 4x4 stuff before I'd left home.
Well I was pretty impressed with the way it was handling itself over what was a pretty challenging, if not completely outrageous track. About 10km along a total of 27km we walked nice & easily down a 250-300mm rock step, but it wasn't long after that there was a distinctly ominous noise from the back. We decided that it was definitely from the left rear.
OK, stop & check and sure enough, the left axle is flopping around in the outer cv like the proverabial in a sock.
Oh dear I thought, that's not good......
Best keep going.....
That was ok till we didn't make it up the next decent hill.
After a couple of tries, we realised that only the front wheels were scratching for traction.
Another crawl underneath & sure enough, the other outer was totalled as well.
Oh dear, that's even worse......
Both rear outer cv's totalled in a gulley, 10km along a remote 27km track on a Sunday afternoon, with no hope of going either forward or back despite a few tries, we were in deepish do do!
The first shaft came out before dark & it looked like both cv's were the same.
Amazingly we had mobile reception as we were line of sight with Callide power station in the (far) distance.
A call to PO Hamish confirmed that the cv's were indeed interchangeable.
Well it's a camper so not a totally bad spot to spend the night......
Even got soap & water to help get the moly grease & dust off....
Next morning the other shaft came out & one goodish one made out of the bits & reinstalled.
Tyres let down till good & baggy & away we went.
We decided to keep going the way we were & the track actually got worse, but we managed to drive out with 2 x front & only 1 x rea r drive!
I was quite relieved.......
Hamish had been busy & found that the closest chance of replacement CVs was Nth Rocky Mechanicals & indeed they had GKNs on the shelf & put other work on hold to fit them to my axle when I arrived next day.
I can highly recommend them!
The 2 that broke were not GKN by the way. I think there's a lesson to be learnt there?
Sorry this turned into a bit of an epistle, but I hope you got a smile out of it : )

Regards

Jim


--
Best regards, Scott Pitcher SPB Consulting
The original bolts (splined heads) have a necked grip. I'e the part with no thread.
This thinner section, preloads the bolt when tightened to specified torque. Using a high tensile cap head screw will fail very regularly. 
I did this twice before getting the right bolts for the job.
Cheers
Mark
The key is the small toothed washer (20) together with the right bolt (with a part thread) (6).
Most of the time the washers are missing leading to the bolts becoming loose over time.







Based on many years of driving T2's and T3's


On 11/09/2017 21:15, mark@spe.com.au [Syncro_T3_Australia] wrote:

The original bolts (splined heads) have a necked grip. I'e the part with no thread.

This thinner section, preloads the bolt when tightened to specified torque. Using a high tensile cap head screw will fail very regularly.
I did this twice before getting the right bolts for the job.
Cheers
Mark

Great story Jim, must have been glad to make it out! Yes dual diff locks have more uses than pushing the syncro to the limits!

Still odd two CV's would let go on the same trip. In the past I have worn some CV's well past their usable life, but have never had one fail completely on me.

Glad your recent trip also went great!

Richard


Hi Jim.
Thanks for that story. It did indeed bring a smile to my face.  Great you got out of there in such a fashion. Hope you have many more travel stories that don't involve repairs/damage.
Cheers. Jim Roger.
Sent from Blue
Thanks for relating your story Jim, especially the bit on swapping the cv's.

The only place I have ever found where having twin diff locks did not work, is my back paddock after inches of rain.
Water logged clay.

Had to use the Fergie.

Even then those two big lug tyres were rotating slightly faster than we were moving forward.
My wife was in the Syncro was shouting : "Don't stop, don't stop."

As a result, now have a WARN M8000 winch on the front so that the Fergie doesn't have to get so close..

Peter



--Original Message Text---
From: jim_m@aapt.net.au [Syncro_T3_Australia]
Date: 11 Sep 2017 01:26:00 +0000





While we're on the topic of cv's, I've been toying with the idea of telling this story since it happened at the beginning of the year.
After 25 yrs of lusting after a Syncro, I finally bought what some forum members would know as "Norbert's Syncro" from Hamish, another member. It ended up having just the specs I wanted with both front & rear diff locks + decoupler. Overkill I was counselled, but the few times I've needed the front diff lock in my 712, 6x6 Pinzgauer, it meant the difference between getting home or not so I was happy! I tidied up a few minor things but despite being concerned by 8 cv's underneath, I thought all was OK, as I couldn't get any warning signs from the usual lock to lock etc tests.
All good so off we went for a 2000km jaunt from FNQ to Brisbane to do the Christmas thing.
On the way home I picked up a friend north of Bunderberg & we headed for Kroombit Tops for a bit of a look. The "Razorback track" to Biloela looked interesting & very suitable to finally try this Syncro out off road, although I hadn't really planned for any serious 4x4 stuff before I'd left home.
Well I was pretty impressed with the way it was handling itself over what was a pretty challenging, if not completely outrageous track. About 10km along a total of 27km we walked nice & easily down a 250-300mm rock step, but it wasn't long after that there was a distinctly ominous noise from the back. We decided that it was definitely from the left rear.
OK, stop & check and sure enough, the left axle is flopping around in the outer cv like the proverabial in a sock.
Oh dear I thought, that's not good......
Best keep going.....
That was ok till we didn't make it up the next decent hill.
After a couple of tries, we realised that only the front wheels were scratching for traction.
Another crawl underneath & sure enough, the other outer was totalled as well.
Oh dear, that's even worse......
Both rear outer cv's totalled in a gulley, 10km along a remote 27km track on a Sunday afternoon, with no hope of going either forward or back despite a few tries, we were in deepish do do!
The first shaft came out before dark & it looked like both cv's were the same.
Amazingly we had mobile reception as we were line of sight with Callide power station in the (far) distance.
A call to PO Hamish confirmed that the cv's were indeed interchangeable.
Well it's a camper so not a totally bad spot to spend the night......
Even got soap & water to help get the moly grease & dust off....
Next morning the other shaft came out & one goodish one made out of the bits & reinstalled.
Tyres let down till good & baggy & away we went.
We decided to keep going the way we were & the track actually got worse, but we managed to drive out with 2 x front & only 1 x rear drive!
I was quite relieved.......
Hamish had been busy & found that the closest chance of replacement CVs was Nth Rocky Mechanicals & indeed they had GKNs on the shelf & put other work on hold to fit them to my axle when I arrived next day.
I can highly recommend them!
The 2 that broke were not GKN by the way. I think there's a lesson to be learnt there?
Sorry this turned into a bit of an epistle, but I hope you got a smile out of it : )

Regards

Jim




I've used both lockers a few times but most memorably going up over the Snowy's on the Mt Pinnibar Track.

So steep and gnarly I was in Granny gear at 3500 rpm hoping like hell the motor didn't cut out. But it did on a slightly less steep incline. Managed to roll back down enough to a relatively flat spot and sleep the night.
Sure enough she fired up in the morning and off we went.

Some years down the track with a Subi motor fitted now I looked into the metallic noise coming from the VC. Turns out the splines in the VC shaft were almost stripped and just hanging on. That could have have really got me stuck. A good used VC and shaft for $700 sorted that and now she's unstoppable.

Mark