I am changing out the cartridge on a Moen single handle positemp shower faucet. I am wondering what type and how much lubricant I should be using on the cartridge prior to inserting it in the "pipe". The package seems to be concerned about using silicaon lubricant.

Yes, Silicone Jel is what Moen recommends. Just grease it lightly on the "O" rings. Never use any Petroleum product such as Vaseline as it will deteriorate and rot neoprene. Good luck, Tom

They sell the lubricant in Home Depot. Otherwise, it is free (in the box) when you purchase new faucet. You should buy the lubricant with the cartridge. Cost: few pennies.