Preparing Surface of Transmission Drain Pan

Video Transcript

"In this clip we're going to talk about surface prep of our transmission pan and of the case of the transmission in order to get a good seal. Alright, I have my transmission pan here and my drain bucket and what we're going to do is begin the surface preparation portion of the transmission pan. First we're going to take and drain out what's left of all that nasty, old transmission fluid. Alright, that's good. I'm going to take and by hand try to peel off as much of the gasket material as possible. This stuff is real sticky, it?s actually, the factory gasket is a fibrous type of paper, and it's designed to seal, so of course it sticks on there real good. I'm going to continue tearing off around it, and get off as much as you can, and what's left you're going to take off with a gasket scraper. The way these gaskets work, if it's not rubber, if it's the fibrous paper type, or a cork type, is they, they're actually designed to leak very slightly in the beginning. The fluid will intrude through capillary action and force this gasket to swell up. The swelling between the transmission pan and the transmission case actually generates the seal. Alright, what we're looking for is a good, clean, shiny surface on it. The gasket will normally stick to one or the other, the trans pan or the transmission case itself. Sometimes a room temperature Vulcanite is used, if it is used you're going to want to reapply RTV instead of a gasket. This is a gasket scraper here. Go ahead and scrape off what's left of the gasket material. Pay very careful attention not to scratch the surface. If you scratch the surface, the scratch may be deeper than the gasket can compromise, causing a leak in your system. A wire wheel, a wire brush can also be used if necessary. You want to be very careful when scraping the gasket off your transmission pan. If you're to put a very deep scratch into the mating surfaces, or the sealing surface, it may be deeper than the gasket can compensate for, thus compromising the seal integrity and causing you a leak. As you can see, there's a raised ridge running around here. That is the portion we're going to pay the most attention to. O.k., once you have as much of the old gasket material scraped off that you can, you're going to use some brake cleaner, to take and spray out your transmission pan, get all the contaminates out from the inside of it. And clean off the surface area here, to see if there's any little gasket particles that still need scraped off. Brake cleaner is the only solvent recommended for use on internal transmission components. You're going to want to take and spray out the inside of the transmission pan, get all the goo out from inside of it, and any gasket material that might've dropped down in it. And spray off the outside so, to avoid any possible contamination during re-installation. On this particular vehicle, being that it has a raised sealing edge, as you can see it around here where bolts go through. The surface is actually raised up, that is the only surface that is necessary to be perfectly clean. The rest of the material between the bolt holes you see here is inconsequential as long as it is lower than the raised sealing surface. That is the proper way to clean off your transmission pan. You're going to repeat that process to the bottom of the transmission case."