When I was inspecting all of my parts before I put together my th400 I noticed that my rear servo piston had alot of scratches on the inner diameter of it. The scratches dont look too deep but they do catch my nail when I run my finger across it. Are these ok or should I scrap it and find another one? I took a picture of it. What do you guys think? Thanks - Justin
Justin, If you can't polish the scratches out, then repalce it. I tried to email you but it came back as a bad address. Jim Burek
Hey Jim what should I use to polish it with? Some really fine emry cloth? What grit should I use? Will these scratches cause a big problem? A pretty big leak? Thanks - Justin
I use either fine emery cloth or the red scothbrite pads. Don't go too heavy on the sanding. What year trans are you building? Inner pistons are different from mid 70 on up. Early ones use a thicker sealing ring than later. Make sure you have the correct one for the trans. Most kits contain the thinner metal style or teflon. Using teflon is not recommended as they tend to leak. My 2 cents, Mark
The transmission is a 70 Cadillac TH400. Are the earlier pistons more desireable to use? Will the thinner sealing rings that come in the kit work with the older servo piston and accumulator piston? Thanks - Justin
To the best of my knowledge, the later thinner sealing ring will not work with the early inner piston. You need to find the early thicker sealing ring or use a later inner piston. You can use the later inner piston/ring with the older servo. The later style inner piston is the more common one and should be easy to find. Mark
