2001 a4 automatic transmission slippes between 3&4 gear

First of all change the automatic transmission fluid!

How to check & change oil in automatic transmission on 2001 Audi A4

At the bottom of the automatic gearbox (tiptronic) you will find 2 threaded plugs on below surface. First (in front of the car) is for emptying, and second is for filling up. Tightening torque is 24 Nm.



Automatic Transmission Fluid (ATF) checking:
1. Requirements for check:
1.1. Vehicle standing on level surface.
1.2. Transmission must not be in fail-safe mode.
1.3. Shift lever in "P" position, parking brake applied.
1.4. Engine idling.
1.5. Air Conditioner and heater OFF.
1.6. ATF temperature must not exceed 104 Fahrenheit degree (40 Celsius degree) at start of test.
1.7. Only ATF with designation ESSO LT 71 141 may be used. Do not use any lubricant additives.
1.8. Automatic Transmission Fluid ATF - part number: G 052 162 A2 (1 liter wrapping)
1.9. An ATF level check when transmission oil temperature is too low results in overfilling, when too high results in underfilling.
2. CAUTION: Too much or too little ATF will affect the operation of the transmission. The ATF level must be checked at regular intervals.
3. The oil level is correct if a slight amount of oil runs out when ATF temperature is between 86 Fahrenheit degree (30 Celsius degree) and 113 F deg (45 C deg) (caused by increase of oil level when heated). For warmer climates, 122 F deg (50 C deg).
4. Hang filled ATF reservoir VAG 1924 as high as possible.
5. Shift lever in "P" position, engine running at idle.
6. Place oil drip pan under transmission oil pan.
7. Remove ATF filler plug (at the bottom of the automatic gearbox you will find 2 threaded plugs on below surface. First (in front of the car) is for emptying, and second is for filling up.
8. With ATF temperature between 86 Fahrenheit degree (30 Celsius degree) and 113 F deg (45 C deg), for warmer climates, 122 F deg (50 C deg), a slight amount of oil will flow from filler hole when ATF level is correct.
9. If necessary drain or top off ATF to attain correct oil level. Top ATF with filler hook from VAG 1924 ATF reservoir. Insert VAG 1924 (tool) ATF reservoir filler hook into filler hole and top off until a slight amount of oil flows from filler hole.
NOTE: Fit filler hook into one of the oil deflector cap slots placed on the filler opening.
CAUTION: Do not press filler hook upward or oil deflector cap can be pushed off.
10. Reinstall ATF filler plug. Tightening torque is 24 Nm.