I am interested in building my FJ55 using a 700r4 and a 203 doubler and a 4 spd case. I know people have mentioned the slop in the extra drivetrain components(with a manual box), but was wondering if anyone has done the doubler with an auto? Was there a lot of slop? Also, what was done with the valvebody in the tranny? I have 'heard' that I need a manual valve body to keep it in First gear (b/c the tranny will want to up shift?), but I thought if I stuck it in "1" on the shifter it would stay there?

Thanks!

Gordon Pritchard in White Rock, B.C. has a TH350 in front of his NP203. I don't believe Gord is on this BB. I can probably find his address if you need it.

you should not have to make any valve body mods at all, just find a shifter that will allow you to physically select 1st gear and keep it there!;)
the slop problem acts out a little differently in an auto setup. you will not experience a lot of backlash due to the face that when you are in gear the geartrain will allready be "loaded up" aka, wanting to go forward or backward.
the interesting part is that the drivetrain will wind up when you apply the brakes after the vehicle has moved. if you're going forward and come to a stop the drivetrain will want to keep going causing the rear of the truck to lift slightly (or more depending on the weight and spring stiffness). to avoid this you can run a slightly higher stall converter but remember that high stall converters run hot and do not appreciate running below stall when driving down the road. 1600-1800 stall should do the trick. that is about stock for a camaro or a 4.3 powered p-u.
hope that helps. :smokin: