the transmission wont shift into 1st gear manually or automatic ?
So you have put the shifter into "1 or L or L1" and the vehicle does not move ? If your answer is "yes", go have the transmission serviced (fluid and filter change) because while they are in there they can stop any issues that might be coming along such as pieces of metal from the bands or band "slip disc" material.
does the vehicle move? if it drives normally and the shifter does not go into 1st gear it is the shifter cable that connects the gear shift to the transmission gear selector, it needs adjustment or replacement can be done at your local repair shop
I am not sure about your 2001, but my 21 audi a8 has an automatic with triptronic shifting, it will not down shift to first until you come to a deadstop or or take off and stay in first gear unless you have your foot on the floor or it shifts out first realquick, ldont know if that helps check your owners manual.
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