I found my B-W autobox was not changing as I would expect. I did not know what fluid was in it, so I drained and re-filled with Comma AQF which made a very noticeable improvement to the up-changes. I have researched a lot about fluid spec. for these gearboxes and it became very clear, do not use any `modern´ fluids as the additives can affect how the bands grip, and although it may work, excessive wear can happen very quickly. Therefore only original spec. fluids suchs as AQF are suitable. This is apparently very important. The message always comes back to Use only original spec. fluid for this B-W box, and change it at correct frequency. I use a local motor factor for the Comma AQF, he orders it in 2x 5 litre packs, and delivers to the door at a very competitive price. Part of a period Ford Zephyr manual refers to this gearbox and states a fluid change is required every 15,000 miles which may seem a small mileage but it is apparently well worth the trouble. It's recommended to work as follows: 1) Warm the oil sufficiently so it will drain easily. Ensure you have a drain-tray that will accept up to 15 pints (approx. 10 pints in gearbox, 5 pints in converter). 2) After switching off, remove the cover under the converter-housing, and get an assistant to slowly turn the engine until the converter drain-plug is accessible through the housing. 3) Remove gearbox drain plug on side of gearbox sump first. 4) Remove torque-converter drain-plug next. 5) Remove pressure take-off drain plug last (small square-headed taper-plug). 6) Replace all plugs when draining is completed, replace cover under converter-housing. If the gearbox sump has never been removed, it may be a good time to remove it and clean it out, as well as the gauze filter. A new B-W gasket has to be used on re-fitting, without any compound. Any work done in the sump area has to be scrupulously clean (essential). 7) Refill the gearbox with 10 pints of AQF or direct equivalent. 8) Handbrake on (chocks if necessary), Start the engine and select L. Idle for 1 minute to transfer oil into the converter. 9) Still in L with engine idling (choke off, slow idle), gradually add required quantity of fluid to bring level to correct mark on the dipstick. This should be approx. 4 to 5 pints. As others have stated the box is sensitive to fluid level so take time to be accurate here. Hope this helps, Giles Lacey Posted by lacey giles 10/04/2015 09:02:52