To use gasket sealant or no gasket sealant on transmission oil pan
The "reusable" transmission oil pan gasket on my 4r100 tranny doesn't look so reusable so I picked up an aftermarket Fel-Pro gasket. As far as I know Fel-Pro in general recommends that no gasket sealant be used with their gaskets, although I have not called them and confirmed this for this particular gasket--it's just an educated guess as it is not one of those cheap cork gaskets but the nice rubber type. What do you think? Should I make a gasket sandwich and use sealant and the gasket or just use the gasket dry? Either way I will torque the tranny oil pan bolts to 11 lb-ft per the manuals instructions.
Also, the manual says nothing about using thread sealant on any of the bolts. I was wondering whether a little thread sealant on the drain bolts like the torque converter and the tranny oil pan wouldn't hurt? In general I do what the manual says--I don't want to screw anything up.
No stuff! If you absolutely must use something just use high tack on one surface to hold the gasket in place. If you use any sealant with the rubber seal it can actually make the rubber seal slippery and push it out from between the pan and the trans making a leak. I have seen this happen to people with oil pan gaskets. They want to do a good job so they make a mess all over with rtv trying to do the right thing and then the rubber gasket gets squeezed out when they tighten the bolts but they don't see it. They fill the car with oil and lo an behold oil is pouring on the ground.
Not only that but any extra "glue" like mentioned will squeeze out and can clog up filters, screens, pump, etc. It is very important that even when you DO have to use rtv is to only use enough to do the job. When the parts are bolted together there should be minimal and an even squish of rtv out from between the parts like in the pic below of the rear end cover for my X. I have seen oil pick up screens nearly completely blocked off from excess rtv being use on oil pans.
I use either gaskets or silicone never both, unless called for at seams etc. in the manuals, then I just apply a dot. Some manufacturers also recommend you coat gaskets with oil (Chelsea and Muncie PTOs come to mind).