Looking at a 92 Ford Econoline based RV, equivalent to the current E450. Which transmission's came in this year of van? I was thinking C6 but I'm probably wrong and it's a E4OD. Has 128k and the fluid smells and looks good. Has a bit of 1-2 shudder. Would do a full flush with Mercon V instead of Mercon and add a couple bottles of Lubeguard Red if it does end up in our driveway.