[CJM72CHEVY]

A lot of the higher-end and better-quality tranny shops I've been around have tranny dynos for testing units prior to installation. There's no way they'll go to the trouble of installing a rebuilt tranny without knowing for a fact that it's right first. They can check shift points, pressures, proper operation and the like. That might be worth looking into. They might just charge a flat-fee for checking one out. At the very least, change the fluid and filter, and look for any damage while doing that. I'd also get the proper service manual and doing any band checks or adjustments that are called for. If it's free, you're not out anything but the labor to install it, and if it doesn't work, you can then have it rebuilt or trade it in on a rebuilt.