I have a couple of questions. I have been using Castrol 20W-50 on our cars now for awhile and seems to do the job. But I have been hearing the Mobil1 will get rid of the lifter noise? Will it? Is it better? And would you recommend channging the trans fluid with Redline. I have a 5speed 88 90. Just curious if it would help or hurt or do nothing. Thanks. Rov randrews@post.smu.edu