Two different TH400 pans
 

I thought I was headed to fixing my leak by finding a pan with a raised rib around the flange perimeter but I might have a problem. My trans has the "can" style filter and I see now it's pickup has a small lower depression in the pan. My "new" pan with the rib does not. Can I use this pan with the can filter pickup?

No. If you're gonna stick with the "can-style" filter, you MUST use the pan with the heel print. If you're handy though, you COULD upgrade to the 67-1/2-later style broiler pan type filter, and then you can use the later pan with dimples. The later style filters do a better job of filtering and are cheaper and easier to procure.

Or else buy a used heel print style pan with a rib. https://www.ebay.com/itm/11631509093...Bk9SR5SSuti8ZQ

I would use Permatex Aviaton 3 to fixate a new cork gasket on your original pan.
Flatten the screw holes if necessary before.

FWIW

Yup. Convert to the newer filter, dump the "heel print" pan.

I will never use gasket sealer on a trans pan. If a "quality" dry gasket doesn't seal, something else is wrong. Common issue is a different leak entirely, drooling down onto the pan gasket--looks like a pan gasket leak but isn't.

Thanks everyone. The filter is new so I'm not going to upgrade at this point. Upon closer inspection I had over tightened the screws pinching the gasket too much in two locations which corresponded to the weep points. I've ensured the pan is flat and screw holes are ok too. I got a new fiber gasket and have Permatex Aviation #3 to the pan but not the transmission. I'll never have to change the fluid/filter again anyway so right or wrong I'll be back in business.

not a expert by any means, so more asking a question on the subject. I would think you could change the pickup tube and filter easily enough, but does the earlier valve body have the bolt hole that suspends the later model filter? I am thinking no?

Correct, so you have to either drill and tap or else swap out VB for a later one.

DaleO I have one of those filters new in the box I will make you a great deal on for your next change if your interested? I might even have two.

Wishing the modern reinforced silicone pan gaskets (ref 4L80, 4R70w) were made for TH400s. Aftermarket would do well to make.

They are. I have one.

Please share link

I did a quick search for the silicone pan gasket they are available everywhere Summit Amazon do a google search not to hard to find. Thanks 65 lamnas