This is likely a rehashed discussion but let revive it.
Transmission screen do or do not use?
I think that you will find that the majority of posters here do use the screen. I have it in all of my Ts.
I can not imagine a convincing argument for NOT using the screen. Every time I clean out my screens I am so thankful that the debris has been caught and is no longer in the oil.
Of course, we must remember to clean the screen on a regular basis. I clean mine at every oil change and about half way between oil changes.
I feel that the screen should be considered standard and needed equipment; all Ts should have them.
My two cents worth. Bill
Bill the argument I've heard is that the screen interferes with oil getting to the back or the transmission.
Are the pictures posted of a typical clean out between oil changes?
There's no reason I can remember given here for not using it. As to the oil returning: a poster recently ran a video of the screen in use. Trans cover off and a very quick run/shutdown. No apparent restrictions however it is a filter and should be checked/cleaned. I too believe there are many in use and no one's complained about it yet.
Typical appearance when you lift the inspection cover of what can be in the oil screen.
Tar like fuzz from modern Scandinavian linings
Unknown soft steel debris
Metallic fuzz from new motor on oil screen magnet, after 20 miles break in.
More stuff collected by the oil screen.
As for any chance of the oil screen preventing flow of oil to the band linings or the triple gears and bushings....I like to enlarge the small holes in the plate above the screen with a step reamer or drill a few extra. Just more assurance oil is being dropped there as the oil flows down the angled catch plate. That lets more than enough flow of oil to the transmission and bands.
A lot of the oil is spun around by the flywheel and the oil gets everywhere. Have run an experiment at low idle and fast idle by video of the oil flow with a clear glass plate over the inspection opening. This showed the oil gobs over the angled catch plate at low speeds, at higher speeds the flow rate over the angled catch plate slows, indicating that most of the oil is being slung way fast by the flywheel and magnets into the crankcase. The test oil screen was std. without my extra holes. The oil screen IMO will not stop flow to the bands or triple gears. Have years of running with oil screens and no issue with triple gears or linings, other than worn linings, the Scandi. tar coated linings being the worst.
Typical available oil screen.
Have enlarged hole oil screens in all my T's. Wouldn't leave home without one
A new oil screen won't quite fit some hogsheads.
They have only 2" of space for the bottom end of the screen.
But the screen as you receive it needs 2½". The easy fix for this is a little body work with a drift and hammer. Just flatten the little bit of screen that doesn't lie down.
After an engine overhaul there will be lots of metal in the oil during break-in.
Even after break-in you will get some. I've seen online comments griping about the wimpy little magnet that came with screens bought from Mac's. The screens I've bought from Chaffin's and Bob's came with nice, big, strong magnets.
Seeing how much non-ferrous debris is caught by the screens, I've moved the magnet up to the flat area above the screen so it doesn't block any of the little screen holes.
The magnet when used is very helpful too.
Comment now, have resisted putting the magnet in any place but on the screen, doesn't seem to block any oil sloshing over the angled plate and down onto the screen.
Like that the screen area is captured with the inspection cover over it, that makes a small compartment to hold that magnet just it case it wants to lift up and move somewhere.
Now maybe it won't as it's attracted to the metal, but....
...stuck up on the angled plate it could shift and fall into the transmission. The T sure has a lot of shaking going on, loosens up most any part. I travel with the T on the car hauler and some pot holes on the interstate are so rough, things pop up and down on the T, jiggled out the ignition key once, and lifted the floorboards. Maybe enough to flip that magnet?
Magnet is trapped if moved, can't pass thru the crease of the cover plate, up and out of the screen room.
Maybe I just respect Murphy's Laws too much.....
#251 "If a thing can pass through an opening...it will"
Tried it but didn't like it.
We tried the screen and quit using it on my dad's '17 touring after the motor and transmission were rebuilt which included an NOS driving plate and NOS fourth main.
After we installed the screen, we experienced oil leaks between the hogs head and fourth main. Once we removed the screen, the problem when away.
At least one other person mentioned a similar problem on the forum in the past.
My opinion is that with all the oil flying around at such great force, more oil than usual deflected or forced back to the rear of the hogshead and pan or maybe it collects back there quicker than it can drain down . I've been scoffed at for mentioning this in the past and have been told this is not plausible but I have no other explanation.
I can't see the screen causing leak between the hogs head and 4th main if they are correctly sealed. If the transmission inspection plate and screen are sealed when the screen is placed and the cover secured it would not leak there either.
However, I can see that there might be more oil getting through the 4th main. That oil would be mixed with grease and leak out around the universal joint.