GM auto transmissions have two "dimples" in each side of the case. Would something like this fit into them or would that be too much strain on those. The factory (Kentmore) tool was like a big C-clamp with dowels that went into these dimples. I doubt there's anyone who has made a homemade version. Is there anyone with a manual trans holder (older 4-speeds)? I would imagine maybe some blocks to stabilize the tail shaft would work. I don't think anything in a clamp would work other than a device with do this stabilizing. The newer 5 & 6-speeds would be another thing.