I just ordered a seal kit for the pump in my '67 Cougar from Mustangs plus. I also got an entirely rebuilt steering set-up (all the parts under the car) from a guy on ebay. Question is, is there a difference if I use ATF as the fluid or conventional power steering fluid. The power steering fluid seems thicker than ATF, and might also help in reducing possible seeping and leaking. Can I even use the other one? Thoughts?