there is a lot of info in the diy forms on this site look there.you can do a stall test to see if the 1st 2nd or reverse are slipping(hold the brake and set the e brake smash the gas watch the take you shouldn't see more then 2500 rpms in 1st 2nd or reverse also test drive and let the trans cool down after each test like 5 min.only hold the gas for 3-6seconds or you could hurt the trans.so example if 1st stalls at 2100rpm and 2nd stalls at 4500rpms 2nd is slipping).