firstfallen... Your joking right? Your a 35 year ASE tech and you THINK posi locks both axles together at all time and don't unlock them???? Have you lost your $#@&*&% mind man?? Posi = ford's term used for limited slip All posi units has a clutch system of some type (spring, cone gears, dog gears, etc) to let one wheel unlock as it turns a turn. Heck even full race lockers does that. I had 2 lockers a mini type gear locker (replaces spider gears) made by powertrax called lockrite and a full carrier locker detroit locker. Both uses springs and dog gears to lock/un lock as its going around a turn. The ONLY fully locked "posi" is a full or mini spool. You sure need to go back and re take your ASE test my friend. Now to answer question. Yes you can weld the spider gears to the side gears and make a locked rear end. Alot of drag racers in the 60's and 70's use to do this. However it is an unsafe thing to do and is now out lawed at the races. With welded spiders, your wheels cant turn at diff speeds as your turning.. So you kinda drag/slid one tire as you turn. You get bucking and tire squeal as you turn.. It can cause axles to break, and due to not unlocking it tends to push the car straight as you try to turn