I don't think the filter on my AW70 has been replaced ever, the previous owner didn't have the fluid flushed while he owned the car. its dark but not burnt. how much fluid would I need just to drop what's in the pan and replace the filter? I'm planning on doing a flush in 10k miles after the filter change, since it won't remove all the fluid.

 

you'd need to drain the transmission pan, which is about 2/3rds of the ATF that is in the full system (the remainder is in the trans cooler, and the torque converter), then remove the pan to access this 'filter', which is really just a thin metal screen. it rarely actually needs changing but its a good idea once in a blue moon to inspect it for metal bits and clean off any accumulated sludge. its really important to have everything really clean when you drop the transmission pan so as not to introduce any grit inside.

 

any idea how many quarts it is? I don't think the filter has been changed in 256k miles, and my pan gasket is leaking so im planning on replacing that as well.

 

Many times the dipstick tube nut won't come undone or strips/shreds/leaks forever after that, so I would recommend taking the starter bolts out and taking the pan off with the dipstick tube still attached.

 

are the problems with the dipstick based on it seizing to the pan?

 

I think the main body of the transmission holds around 4-5 quarts, and there's 2-3 more in the rest of the system.

I would warm things up, and check the fluid level so you know how much is in it.... dump the ATF from the pan, remove, inspect, and clean the filter, reassemble (ALWAYS using a new gasket), add the amount that came out back in through the dipstick tube, then disconnect the transmission fluid line at the radiator, hook up a clear vinyl hose to that pipe and run it into a graduated bucket, start the engine and let it idle, and for every dirty quart that comes out add a fresh quart in, when its running clear, stop the engine, reconnect the cooler pipe, verify that the total amount that came out equals the amount you've added, add some more if needed, then drive around for 20 mins to warm up the transmission and with the engine idling check the trans dipstick to ensure the level is correct.

you definitely want a good transmission funnel for this job, the ones I've used look like this: I generally shorten that vinyl hose way up, and rig up some sort of coat hanger stand to hold the funnel top upright directly over the trans dipstick. the blue collar is a valve you can close or open to control the transmission fluid flow out of the funnel

 

Yes - the dipstick tube may not come loose from the pan. And when it does not - it will be a problem. It was easy to fix in the 80's-90's with used or new parts- but now?

And that's a cool funnel - the only one I found that would work, (the dipstick end was always too large) was a yellow funnel from BG products (the additive people that I eventually rejected) - but their yellow funnel ends are small enough to fit in a Volvo dipstick tube to be able to pour in Trans fluid without spilling.

 

thanks for the tips! I will be doing this in the near future..