How did the 93 S4 locking differential work? - 1993 Audi S4

remove differential cover and rotate carrier look in the area around the axle gear small teeth can be seen with little gears that come to a flywheel weight governor (g80) that spins and tightens the axle gears against the carrier creating posi. works only under power

Put back on H2 or all normal, remove both battery cables from the battery, without touching the battery, hold the positive and the negative cables together for 30 seconds, then return the cables to the proper posts on the battery. This will drain all memory at the ECU, the next 10 or so miles , under normal driving will re- teach the computer. I hope this improves the issue!

No.

The baisc differences are ratio , locking or open carrier and drum or disc brake.There are two ratios that are common and that is 3:41 and 3:73 to one. 3:08 (smog/emissions) and 4:10(performance/off road) were rare.Most jimmys did not have a locking rear diff so i will not elaborate on this.The housing is the same for drum and disc brakes even though the hardware is different.

FOUR-WHEEL DRIVE SYSTEM

(a) Four-wheel drive control

Use the four-wheel drive control lever and center

differential lock button to select the following transfer and

center differential modes.

The "H" and "L" position of the four-wheel drive control lever

provides either lock or unlock mode of the center differential

depending on the center differential lock button position.

Use the center differential lock system if your wheels get stuck

in a ditch, or when you are driving on a slippery or bumpy

surface. When the center differential is locked, the vehicle

stability control system is automatically turned off and the

center differential lock and "VSC OFF" indicator lights come on

because the function that controls engine performance

As soon as the center differential lock switch is turned

on, the "VSC OFF" indicator light comes on. After the

wheels are out of the ditch or off the slippery or bumpy

surface, turn the center differential lock switch off.

Make sure the center differential lock indicator light and

vehicle stability control system off indicator light turn

off.

"H" (high speed position, center differential unlocked):

Lever at "H", center differential lock button left out

Use this for normal driving on all types of roads, from dry

hard-surfaced roads to wet, icy or snow-covered roads. This

position gives greater economy, quietest ride, least wear and

better vehicle control.

"H" (high speed position, center differential locked): Lever

at "H", center differential lock button pushed in

Use this for greater traction when you experience a loss of

power, such as wheel slipping, in the center differential unlock

mode.

"N" (neutral position): Lever at "N"

No power is delivered to the wheels. The vehicle must be

stopped.

"L" (low speed position, center differential unlocked):

Lever at "L", center differential lock button left out

Use this for maximum power and traction. Use this for climbing

or descending steep hills, off-road driving, and hard pulling in

sand or mud.

In this mode, the braking feeling that occurs when the wheels

are negotiating a sharp corner is further reduced than in the "L"

(low position, center differential locked) mode.

"L" (low speed position, center differential locked): Lever

at "L", center differential lock button pushed in

Use this for maximum power and traction. Use this for hard

pulling in situations the vehicle cannot negotiate even in the "L"

(low speed position, center differential unlocked) mode. Also,

using this mode when driving down steep off-road inclines will

help contribute to increased vehicle stability.

https://secure.drivers.lexus.com/lexusdrivers/info/my-lexus/resources/submit-owners-manual-search.do

Please copy and paste the link above and it will take you to the lexus site. There you will find the owners manual and you can download whatever sections you need for free.

Hope this helps.

easy way to tell have someone watch the tires as you do a burn out if one tire spins and the other dont then its not locked if both spin then its locked have fun.

Hi, I had the same problem with a stuck differential plug on an old ollsmobile I had many years ago. What I did was apply a liberal amount of penatrating oil on the plug and them left it overnight. The next day, I took an air hammer and carefully hit the plug for several minutes. That loosened it enough so I could remove it. Hope this helps!

It sounds like your front 4x4 actuator on the front differential has locked up. It's common to happen and the fork that engages the 4X4 in the differential is still locked up or partially locked up.
On the full size, the front actuator is electric, not vacuum.

When in 4wd mode, a switch on top of the transfer case conducts 12 volts out to the actuator. Wire #50 (brown) is the 12v feed, and it conducts to the light blue wire (#900) to the actuator.
When shifted out of 4wd, the switch opens up and no voltage goes to the actuator.

Check voltage at the connector for the front actuator (at the front differential - it looks like a large bullet that threads into the front diff.) If it has 12 volts, the actuator is the problem. If it does not have 12 volts, check the transfer case switch and the power feed to the transfer case.

I'll assume it is the actuator, if the plug to the actuator is getting 12 volts when in 4wd.
The way this actuator works, is it is a sealed chamber that gets heated by voltage. When it heats, the pin in the end swells and pushes a shift fork in the front differential. The shift fork engages a spline on the passenger side of the differential, and boom! you have 4WD.

GM offered an upgrade to this actuator that is a motor instead of a heated device. However, it requires a small harness addition, a spacer, and a new actuator. It is about a $150 to $200 option.

If I were you, I would buy a new heated actuator. They are available at most auto parts stores, and are about $90. They are also on eBay for about $55 plus shipping. These are very easy to change - just thread out the old one, and thread in a new one.

Good luck. The actuator is usually the problem 90% of time but recheck all of the wire harness just to maker sure there is no short before replacing any parts.
http://www.getdieselpower.com/misc_auto/actuator_upgrade/GM_TRUCK_4X4_ACTUATOR_UPGRADE.html

Plugged filter or the rack is bypassing one of the clyinders but there should be no pressure there unless it's an inclosed system.

pressed the c diff lock by accident - now the alarm wont go off when I turn it off? What should I do?