Trans. Pan Gasket Question

I just put the pan back on my 727 using a new rubber gasket and also a thin coat of Ultra Black. I tightened the pan bolts to 150 in/lbs per the book and assumed all was good and started cleaning up. Went back to the trans. to pick up some tools and happen to look at the pan and the gasket was squirting out from the pan in two spots (both corners on passenger side). Is 150 in/lbs. too much for a rubber gasket? I know people are gonna say I should have used the Mopar hard gasket but the last time I used one of those it leaked too so I just used the rubber gasket since I already had it. I loosened all the bolts and the gasket receded back into place on it's own so should I just snug the bolts up till they are snug?

Have you check THAT pan for flatness? How about the bolt holes, are they flat or dimpled in? How about the bottom sealing ledge on the tranny?
Either one can and probably will make them seep or leak

When you say rubber is that the one that’s stiff with the ridges? I’ve started using that one with no sealer and it stays dry and tight. 150” pounds sounds tight.

The backbone Mopar gasket does not leak.

IF - you have an undamaged, flat pan flange, no damage to the case, etc. You can’t overtighten them either.

Adding silicone to a rubber gasket just lubes them up allowing them to squirt out. If your pan leaked with the Mopar gasket it’s going to leak with the others unless you slop a tube of RTV all over the place.

Gasket or gasket maker. Not both. I prefer gasket. Specifically, the fiber style.Stamped steel pan has to be straight. 120 lbin. or so. No more than 150.

Rule #1: Never install a rubber gasket with RTV silicone. Why? Because rubber is not compressible... it is deformable. So, IF you apply RTV silicone spread across a rubber gasket, its the same as spreading grease across it. the gasket will simply slide and want to split/deform very easily. You will never find a gasket manufacturer with directions to apply RTV silicone across a rubber gasket. Rubber gaskets are always best installed DRY without any wet chemical.

Rule #2: Check for flatness... both surfaces must be flat (stamped pans, etc tend to have distortion, especially at the bolt holes... replace or flatten as needed.

Rule #3: Clean all threadings... so to reduce and eliminate unwanted friction.

Rule #4: Tighten to manufacturer's specifications... avoid over-tightening.

Remember, again, that rubber is not compressible... its deformable and only by about about 30% of its thickness... squeezed any more than that and it'll split apart. (Cork-rubber, by comparison, can be compressed 50%... more forgiving to out-of-flatness and irregular surface imperfections.)

I 'm a former gasket engineer from a major leading company... and I wrote the instructions within their gasket sets.

Stock pan gets the factory style cork, dry. The 518 pan can use the reusable steel core rubber coated gasket, also dry.
Doug

Steel core moroso blue gaskets for valve covers and pan gaskets for me. No leaks and no gasket blowout. Need longer studs tho

Good stuff to know here - GREAT thread!

if you are using a cast aluminum pan, make sure your bolts are long enough to engage enough threads in the transmission case to prevent stripping the threads. [you know : "tighten them until they strip or break, then back them off 1/2 turn"! as i always say. ]
or use studs, which i prefer when using a cast pan.

I just bought this gasket. Any feed back on this one? https://www.ebay.com/itm/115529800890