Tee, you would really need to have the tranny replaced. That crack will get bigger, no way around it.
You will really have to weigh your options out and look to see what they are, as to what you should do.
Option 1) Find a lower mileage tour and have the tranny yanked out. Send it off to a tranny shop and have them rebuild it. Cottmans will do this, but they don't like doing it.
The place is actually quite fair. They are the ones that rebuilt mine for me. See the thread above titled, "My CD4E Shopping Experience". Cost will depend on the shops labor rates. If all goes well and no work is required on the replacement tranny, I would say a good guess would be between $500 - $850. Somewhere in there. If the replacment unit will require rebuilding itself, then look at somewhere between $1200 - $2500.
Option 2) Buy a remain unit, which is just a completely rebuilt unit, and "find" someone to install it for you. Labor cost will run about the same here.
Notice in Option 2 I have the word "find" in quotes like that! I talked to roughly 10 shops in my area and could not find anyone that would do it. You can of course install it yourself, that is if you are good with a wrench.
Good luck. If you have any other questions you can of course post them here, but feel free to PM if you like.
