Can external water cause tranny failure?

[AnotherWs6]

Hi all, if you click the link below you will get my story. I started that thread looking for tranny advice. Well I already ordered and paid for a new one, but I am perplexed.

http://67-72chevytrucks.com/vboard/s...75#post7638775

In a nut shell -

Driving on highway

Hear loud popping sound, hear pressurized liquid

Pull over, hard to see, but diagnoses is hole in heater core

Top off coolant in attempt to make it home, pull back on highway

Get up to 30mph and hear harsh, loud buzzing from below

Pull over again, shut off truck, put truck in park, hop out, truck slowly rolling away, hop back in, turn wheel hard right to bump against guardrail

Look around and under truck a little bit, see nothing new, start truck, put in reverse heard harsh, loud buzzing.

Put truck in drive, engages with no noise. Able to drive up to flatbed with no issue.

1 - Is it possible for pressurized liquid to "mess up" the transmission's or transfer case's electronics?

2 - How are park and reverse related? Why is at least 1st gear still ok?

I know I'm not gonna get lucky, change a fuse and have everything work again, but I would like to know if I either jumped the gun on the new tranny, and/or if I need to be looking out for/changing anything else when I install the new tranny.

I know that some of you know a LOOOOOOT more than I do about how auto trannys work. Hoping yhat you can shed some much wanted light on this for me/ Thank you.