Any shim that was installed behind the back pinion bearing race wouldn't be just a piece of metal jammed in there. It'd be a complete circular shim that fits the back side of the race against the case well. In other words it'll look like the shim behind the bearing but larger. I've found it's easier to read the pattern when you don't use so much marking grease. When it's real thick like you put on it can smear. You don't have to completely remove the grease. Take enough off so it's not smearing out so much and level it out with your grease brush. Really doesn't take a lot of grease. When you get the grease smoothed out rotate it to where it's just about to contact the pinion teeth then hold the pinion yoke with one hand real tight and with the other hand rotate the carrier until the grease patch is completely through then backwards to get the coast pattern. I have never had to apply pressure via any other means than just the resistance I apply by holding the pinion as tight as I can. Hope that makes sense.
