Major Coolant Leak

91 Dodge D150 1/2 ton truck with a 318 (5.2L). Approx. 135K miles. Noticed a leaking freeze plug right behind the starter. Removed the starter & replaced the offending plug. I’ve also replaced other plugs on the block as needed in the past. While I had the starter out, I went ahead and replaced it as it was getting old & tired. After buttoning everything up while adding coolant, I got a major waterfall coming out between the trans and the engine block.

My project for today is to remove the transmission so I can get to the rear plugs and replace. How many plugs are back there? I’m obviously changing all the plugs back there along with the rear main seal. Is there any advantage going with the brass plugs or should I just stick with the regular ones?

Brass does not rust. If the original are steel, I would go with brass.

I would stay with the aluminized steel plugs. Brass is a less active metal than iron, therefore when there is dissimilar metal corrosion, the iron block will corrode instead of the plug. Which would you rather have corrode, the block or the plug. There is also less dissimilar metal corrosion between iron and steel than between iron and brass as they are less dissimilar.

Besides the old steel plug lasted for 24 years now.

I will just add that it would be a good idea to replace the front pump seal (torque converter seal) in the transmission if it’s an automatic.
If you don’t Murphy’s Law states it will leak right after it’s put back together.