I'm doing a rough math but let's assume $250 in a fluid change - $20 per quart, new filter and gasket.

That's 7-8% of what a tranny rebuild would be. Regardless, it sounds like th tranny needs a rebuild....

It's all relative I suppose and maybe your do the $250 cost and hope you didn't just plunk that money down when you really needed a rebuild...

When it slams into gear like that though, I'm errring on the rebuild side