Newbie here and I need some expert advice. I have a 1991 ext. cab 4wd with the 22re with an a340f auto tranny. I bought a junk 1989 truck with a good 5 spd. and I am going to convert my auto to a manual. My questions are 1.) Do I have to hook up a neutral safety switch on the manual tranny for the truck to start? 2.) Will this mess with my computer, will the engine run correctly, can I use the computer that came in my truck that was equipped with an auto from the factory without any problems? 3.) Which driveshaft will have to be made longer or shorter? The manual tranny came out of a regualr cab pickup, and it's going in an ext. cab pickup. I have already switched the pedals, mounted the clutch master cylinder, installed the flywheel, clutch, pressure plate, throw out bearing and pilot bearing. I was also going to change the gear oil in the tranny and the transfer case. The book calls for 75w90, can I use 80w90? Any advice at all would be greatly appreciated. Thanks for your time guys.