'93 1500 2wd Autotrans Problem!!!

I Noticed My Truck Would Vibrated At A Certian Speed.(35mph) I Checked The Fluid Level And It Was Low. To The Tip Of The Dip Stick. I Added Some Highmileage Fluid (1qt)recommended By The Guy At Autozone, And It Ran Fine For A Couple Of Days. Then Started To Slip Out Of Gears While Driving A Few Miles. No Fwd Or Rev. So I Turned Off The Engine. Started It Back Up And The Tranny Started Working Again But Only A Few Miles. So I Checked Underneath And Noticed The Wiring Harness To The Tranny Had About 5 Wires Burnt Together. I Seperated The Wires And Taped Them Back Up. Then Noticed Fluid Leaking From The Pan Bolts. Each One Was So Loose I Could Unscrew Them By Hand. Checked Fluid Level And Now It Was Way Too High!! An Inch Over The Hot Mark. And Also Was Dark Brown And Smelled Burnt. Now The Tranny Won't Work At All. So I Decided To Do A Filter And Fluid Change.(pan Only) Now Only 1st 2nd And Rev Work Great. But Drive Or Overdrive Still Slip Out. Do I Need To Replace The Tranny!!!! Or Is There Something I Can Try That May Resolve My Issue.

Had the same problem with my 2001 4WD as far as the overdrive slipping problem. I put Lucas "stop slip" in the trans and now it works fine. Took a couple of days before it was 100%. Not to sound like an advertisement, but that Lucas Stop Slip is a miracle product.