fine mesh filter?
 

Looks like I have to add some ATF to my '87 300SDL.The owners manual says to use a "fine mesh filter".What is "fine"? Should I use a nylon stocking in the funnel? A piece of door screen? Is this really necessary or just super cautious?? Also...do I add it while the engine is running?? Thanks a lot for any of the usual good advice.

screen probably not needed
 

transmissions are super sensitive. any lint from a rag can clog up a transmission.

just be careful that your funnel is very clean and you don't contaminate the fluid in any way

when you wipe your dipstick down don't accidently introduce any crud into the system - make sure it's clean before reinserting

brass or stainless mesh
 

There are available, at low cost, brass or stainless fine mesh screens, which won't pass water. I forget the mesh size, but I believe you're only talking five to twenty dollars for a funnel with built-in fine mesh. I think it's a good idea to put a little coarser mesh, with a space in between the two mesh filter's to keep the finest one from plugging with large debris (such as the lint size contaminants mentioned by one of our member's). There are also "paper" micron-size throw-away membrane's you can get from scientific supply houses.

I never heard of going to that extreme to add ATF, but, whatever.....

A diesel prefilter and some 5/16 hose should do he job nicely. If you get a straight prefilter like from a 115 240D, that would be easier than using the 90 degree angled prefilter from the later models.

Thanks to all for the prompt responses and advice.Just added the Mobil 1 ATF with EXTREME caution,spotless funnel,piece of leather to wipe the dipstick,etc...should be fine.Thanks!

adding ATF
 

I've always : Cleaned the dipstick and the top of the tube with Brake Parts
Cleaner before opening (shielding any other possible affected surfaces with rags),used a small plastic funnel that I've just blown out (inside and out) with BPC AND a COFFEE FILTER in the funnel as I slowly add the ATF.

Here's what I do.

Clean the funnel with a rag or paper towel. Then I pour a little ATF through into a waste recepticle. Then use to pour new ATF into tranny.
No need for any filters.

Danny

Use a nice clean inline fuel filter, that will filter out all the lint etc.

funnels
 

I found a great funnel at Walmart. It comes with a gooseneck tube, fine mesh filter, lids for both ends and you can start and stop flow by twisting the base. I bought two (at $5 or so apiece), one for ATF and one for hydralic fluid. The lids keep all debris out of funnel.