I have a '92 300D 2.5 Turbo. It is equipped with the ASD (locking differential). Looking at the engine bay, there is a tank on the drivers side that holds hydraulic fluid that is connected to the power steering pump. There are hydraulic lines that lead down towards the bottom of the car and connect to the differential and then back to to the power steering pump. My question: Is the power steering fluid the same as the ASD fluid? Why the two reservoirs? How often do you change it? How do you change it? Its kind of confusing because the maintenance disk that I have mentions nothing about how to change this fluid. Thanks for the response.

Herb
'82 240D
'87 300SDL
'92 300D 2.5 Turbo

Anybody else have the locking differential on their cars?

Herb
'82 240D
'87 300SDL
'92 300D 2.5 Turbo

Sorry. Wish I could help. My '91 doesn't have it. Is that the same as positraction?

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'91 300D 2.5 Turbo 330K
'00 VW TDI Golf, 190K
'67 BMW R50/2
'73 Norton Commando Interstate

I'd also like to know since my dad's car does have the ASD box on the engine.

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Audi TT

Supposedly, ASD was introduced on diesel engine cars as an option beginning in 1991. It is described in the owners manual as follows:

"The automatic locking differential engages when there is a difference in speed (slip) between the front and rear wheels of over 1.2 mph and the vehicle speed is less than 15.5 mph. It will disengage at speeds above 16.2 mph.

The yellow function indicator in the speedometer comes on whenever there is a difference in speed between the front and rear wheels of over 1.2 mph warning of slippery road conditions."

Herb
'82 240D
'87 300SDL
'92 300D 2.5 Turbo