My 2002 4.0 5 speed (NV3550) will be getting some fresh fluid in the trans tomorrow (If I can escape from work). I can get the Royal Purple Synchromax from the local pep boys. Any recommendation on this oil either positive or negative. I am getting up in miles (148k) and not sure what the prior owner had done. Starting to get a little bit of grinding and tougher than normal shifts. Any other oil I should consider? I'd go with redline MTL, but that seems like it needs to be shipped.