A common issue we run into when a customer calls in looking for a transmission coupler is determining which coupler they need. Sometimes we can look up the engine / transmission to get an idea of what they need. However, since our charts are not necessarily 100% accurate and there may have been modifications made to the engine or transmission, we always want to verify coupler dimensions. The difficulty arises in communicating which measurements we want. As a solution, Buck Algonquin / Hydrasearch has provided us the coupler measurement diagram below. If you have any questions, please give us a call or send an email. Click here for the shaft couplers we offer online. If you need a coupler we do not have on our website, please call or email.