95 honda civic tranny problem

when cold my tranny slips outta drive and makes this weird sound only one time. i was stuck in low2 this morning then after work i went to reverse and it dont shift into reverse had to be pushed out of stall now what
get tranny rebuilt or buy one from salvage yard? help

Fluid level?

Buying from salvage yard can be tricky, most of items from them doesn't last long. Any budget for a new one? find out how much it will cost you to rebuilt it. Autopartswarehouse (http://stores.ebay.com/Auto-Parts-Warehouse)can be good place to check price parts.