What sealer do you guys recommend?

I have to guarantee my transmissions don't leak. I use Lock-tite "Gasket Maker" on all the gaskets - a .010" film on both sides (about as little as you can spread on the gasket) No problem to clean up - it comes off with the gasket and if there is any residue it peals off like a plastic film. Leave the metal clean and ready for more.

That's good to know, Paul. If it really cleans-up that easy, I'll grab some for when I have a problem child. Thanks for the easy-clean pointer!

David

I have tried nearly all the sealers there are and I have found the best and worst sealers for each application. Trannys should NEVER have silicone RTV on them - even if you get the case clean enough to get the RTV to bond, you can never get all of the RTV off without sanding. Most transmission fluids will disolve the silicone sealers and it ends up in one or more passages. RTV works well for water but so does Gasket Maker - and the gasket maker is so much easier to clean that I use it for everything but head and exhaust manifold gaskets. Silver chrome paint works best for head gaskets (tes, even the imprinted ones), and a good metal to metal contact works best on exhaust manifolds. Headers won't seal this way unless the flanges are at least 3/8" thick.

Paul that is the 515 dark red stuff???

The stuff that I have been using is blue-green and thick - not runny at all. I can't tell you what the number is because it has the Caterpillar part number on it. I used to get it for free but I am finally on my last tube so I will have to get some from the auto parts house unless I can find another Caterpillar mechanic. I should probably just get it at the parts store and then I will have the number. I can give you the Caterpillar number - but that wouldn't help unless you knew a mechanic or wanted to pay the higher price for the Caterpillar name.