Diff Lock

Came out from a friends house last night to find I had a flat rear tyre.
Locked the central diff lock as per handbook instruction and changed wheel.

Drove home about a mile with the diff still engaged as I could not get it to
disengage.
I tried reversing (maybe not enough) to free it .
I could "feel it" winding up .
When I got home I jacked the rear axle and the transmission unwound(the
wheels moved)

Question: 1 Is this likely to cause any damage to the drive line.(Auto box)

2 Is it possible to unlock the central diff by reversing a
short distance.


--
Simon Mills
Melton Vic.
Australia
98 Disco Tdi

On Sat, 25 Sep 2004 23:51:02 GMT, "Simon Mills" <smil2921remove this
[email protected]> wrote:

>Question: 1 Is this likely to cause any damage to the drive line.(Auto box)
>
Eventually yes it would damage the driveline, over a short distance
unlikely unless you were very heavy with the right foot and making
tight turns.
> 2 Is it possible to unlock the central diff by reversing a
>short distance.

The secret is to get no windup in the drive line this can be by
driving a short distance in reverse, putting one set of wheels in the
dirt/grass/or other less tractive surface. In a manual its usually
easiest to quickly back off the throttle and it should disengage. In
earlier vehicles with the vacuum diff lock sometimes a squirt of WD40
into the diff lock switch worked wonders as they tend to leak air into
the switch.

On Sat, 25 Sep 2004 23:51:02 GMT, "Simon Mills" <smil2921remove this
[email protected]> wrote:

>Question: 1 Is this likely to cause any damage to the drive line.(Auto box)

IMO no, the cost is in fuel consumption and tyre scrub.

>
> 2 Is it possible to unlock the central diff by reversing a
>short distance.

Should be, the trick is to make the load come off the central diff so
the dogs can retract under their spring pressure. Making the front
drive train cover more distance than the back, or vice versa, is what
allows this. So driving backwards turning from lock to lock should
achieve this. Spinning a wheel on soft ground and slowing down
sometimes works.

AJH

In message <[email protected]>, Mr. Nice.
<[email protected]> writes
>Twas Sat, 25 Sep 2004 23:51:02 GMT when "Simon Mills" <smil2921remove
>this [email protected]> put finger to keyboard producing:
>
>>Came out from a friends house last night to find I had a flat rear tyre.
>>Locked the central diff lock as per handbook instruction and changed wheel.
>>
>>Drove home about a mile with the diff still engaged as I could not get it to
>>disengage.
>>I tried reversing (maybe not enough) to free it .
>>I could "feel it" winding up .
>>When I got home I jacked the rear axle and the transmission unwound(the
>>wheels moved)
>>
>>Question: 1 Is this likely to cause any damage to the drive line.(Auto box)
>
>Unlikely
>
>> 2 Is it possible to unlock the central diff by reversing a
>>short distance.
>
>when mine stays locked I find reversing usually does the trick, 10
>feet or so.
> I hear also bumping up a kerb lets one wheel spin freely for a moment
>and can do the job (not needed to try that myself).
>
>
>Regards.
>Mark.(AKA, Mr.Nice.)
I believe that's mandatory about every 15 miles or so in a 6 wheel drive
Scammel!!
--
hugh
Reply to address is valid at the time of posting

In message <[email protected]>,
[email protected] writes
>On Sat, 25 Sep 2004 23:51:02 GMT, "Simon Mills" <smil2921remove this
>[email protected]> wrote:
>
>>Question: 1 Is this likely to cause any damage to the drive line.(Auto box)
>
>IMO no, the cost is in fuel consumption and tyre scrub.
>
>>
>
<Snip>
The answer is either "no" or a big bang and something broken - e.g. half
shaft. I don't think there's an in between.
--
hugh
Reply to address is valid at the time of posting