[urq] Diff Locks

[Brandon Rogers]

huhh.  interesting.  thanks.  On Lister suggested checking the rubber hoses 
at the back - I'll go ahead and do that since they are 21 yrs old 
anyway...and I'll assume it will still vibrate and we'll call it good.

thanks again.

Brandon
----- Original Message ----- 
From: "Martin Pajak" <Martin at quattro.ca>
To: <Louis_Alain_Richard at computerhorizons.com>; "Brandon Rogers" 
<brogers at terrix.com>
Cc: "Urq List" <urq at audifans.com>
Sent: Monday, June 06, 2005 1:02 PM
Subject: Re: [urq] Diff Locks


> Brandon,
>
> Louis-Alain is right, all of my cars Ur-q and 4kqs do it.
> You have a stress from one driveshaft "trying" to turn the wheel backwards 
> while another "trying" to turn it forwards (at a standstill).  That is due 
> to difference in rolling diameter between tires, front back (load), and 
> wear.
>
> Think of it as turning a slow corner with diffs locked and then stopping 
> in the middle of the turn, the stress will remain untill you start turning 
> the other way...  it even worse with both diffs locked. :)
>
> Hope this helps.
> Martin Pajak
>
> http://www.quattro.ca
>
>
> ---------- Original Message ----------------------------------
> From: "Brandon Rogers" <brogers at terrix.com>
> Reply-To: Brandon Rogers <brogers at terrix.com>
> Date:  Mon, 6 Jun 2005 12:47:13 -0600
>
>>yeah but it vibrates (rough idle) when the car is stationary.  I don't see 
>>how those factors can cause vibration when  the car ain't moving.
>>
>>Brandon
>>  ----- Original Message ----- 
>>  From: Louis_Alain_Richard at computerhorizons.com
>>  To: Brandon Rogers
>>  Cc: Urq List
>>  Sent: Monday, June 06, 2005 12:18 PM
>>  Subject: Re: [urq] Diff Locks
>>
>>
>>  I don't think so.
>>
>>  I have the same behaviour on my car. My conclusion is "drivetrain 
>> stress" or windup.
>>
>>  As each wheel as a different diameter (pressure, wear, weight on each 
>> axle, etc) then one axle as a greater developpment than the other. When 
>> rolling, this difference is absorbed in the slippage of each tire.
>>
>>  When you coast to a stop on an adherent surface with the center diff 
>> locked, it means that one axle has a rotational load and this put a 
>> stress on the engine/transmission/diff mounts. This is the vibration you 
>> feel in the body.
>>
>>  As a proof of this, if you can't have the center diff to disengage (when 
>> the car is stopped), it means there is a load on the dog clutch, CQFD.
>>
>>  To play with my theory, deflate your font tires to 25 psi and inflate 
>> the rears to 35 psi. Lock the diffs, roll 100 ft straight ahead and 
>> notice the vibration. Then do the opposite (35 front, 25 rear). You'll 
>> see that the vibration is a lot less present.
>>
>>  Louis-Alain
>>
>>
>>
>>  -----urq-bounces at audifans.com wrote: -----
>>
>>
>>    To: "Urq List" <urq at audifans.com>
>>    From: "Brandon Rogers" <brogers at terrix.com>
>>    Sent by: urq-bounces at audifans.com
>>    Date: 6/6/2005 12:17
>>    Subject: [urq] Diff Locks
>>
>>    GUys-
>>    did some highway driving in our downpour over the weekend so I locked 
>> the center diff - when I came to a stop I realized I had forgotten to 
>> unlock the diffs - I could tell the diffs were still locked (other than 
>> the fact the green light was still on) because the motor was idling a 
>> little rough.  Turned the dial to unlocked and of course the roughness 
>> went away.
>>
>>    Does this mean I have a vacuum leak somewhere in the lock system?
>>
>>    TIA
>>
>>    Brandon
>>  =
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>