Symmons Temptrol leaking question

Hello all,
With the popularity of this product, I'm sure this question has been asked and answered before, but doing a search, I cannot seem to find it.

I have a Temptrol tub/shower valve that won't shut off completely. It's dripping about a drop p/sec. To simplify and expedite what I thought would be a fix, I replaced the entire spindle (TA10), but this did not solve the problem. It leaked just as much.
So, I put the original back in and I'm back at square 1. Is this a 'seat' problem I need to buy special tools for? I'm at a loss and would appreciate any help. Thanks

Yes, there are hot and cold seats which need to be replaced. You absolutely must have the symmons seat tools. All this should be available at the same place you got the TA10.

This shows you all the details> http://www.symmons.com/ins/temptrol_ins.pdf

Thank you.

Thank you!!!