1991 Audi 90 Q&A
1991 Audi 90 Question: Where is the drain and fill plug for the Torque converter.
I am changing the auto trans fluid and specs call for dextron and hypoid gear oil. Not sure where the drain/fill plug is for the torque converter. - Visitor
MOST torque converters in cars do NOT have ways to drain and refill them... The best way to flush out and replace the ATF, is to connect the lines going to the transmission fluid cooler (either inside radiator or the air-oli cooler), and first replace all the ATF inside the transmission pan, replacing the filter and cleaning the magnet inside the pan. Then connect the out line from the trans to the ATF cooler to discharge the ATF and place a funnel to replace the ATF. Get ready about 1.3 times the full capacity of the transmission number of new ATF quarts, use vynil transparent hose in order to see the color of the fluid as it comes out of the circuit, and start the engine in park. The trans pump will circulate the old ATF out of the transmission, at the same time you have to carefully restore approximately same quantity of new ATF in order to maintain the normal fluid level. By using 30% of extra new ATF, you will be able to "flush" the torque converter and then the transmission fluid will look exactly like the new fluid: a cherry, light red completely transparent fluid, that is indistinguishable from the new one. That is the PROPER way to do it. By only changing the ATF inside the trans pan, you are only changing about half of the total; therefore, you have to flush the converter's fluid out. More info at allpar.com in repairs. - amclaussen