Every TTY bolt I've ever used had specific instructions on the loading. The +90* is different from what I recall being to apply torque in stages, ie, x lb-ft then to y lb-ft. There are several TTY bolts on the GT.
Finished updating the bolts per TSB 06-23-8. The old bolts and washers looked really good. None of them were broken. All came out without too much trouble and all felt evenly torqued. Putting the new bolts in and turning them 90 degrees after 21 ft-lb didn't feel anywhere near 295 ft-lb. Felt more like 70 ft-lb.
Finished updating the bolts per TSB 06-23-8. The old bolts and washers looked really good. None of them were broken. All came out without too much trouble and all felt evenly torqued. Putting the new bolts in and turning them 90 degrees after 21 ft-lb didn't feel anywhere near 295 ft-lb. Felt more like 70 ft-lb.
Take one of those OEM washers and put it on a very flat surface with the bolt head side up. It will be "cupped" and it will rock back and forth on a flat surface....