[ekrupa2]

Jim - I am by no means a mechanic, and I only posted as I almost have the same set up us you. I speculate this is a heat issue...rather than a problem with the trans. That clutch slave line is very close to the headers and I tend to notice a change in shifting manners when sitting in stop and go traffic. But I stress nowhere to the extremes you have mentioned. I do know when I adjust my slave (via shims), I can change the adjustment only 1/32 of an inch to induce a grind when going from forward to reverse...and now know by feel where the sweet spot is. When in stop and go traffic, first gear can chatter a bit if my clutch let out is not perfect when there is no air movement cooling things down. This is not the case during non stop and go driving. I did switch to hi-temp fluid, and also installed a heat shield above the brake/clutch line prior to my motor drop. Good luck and I do hope you find the cause of your issue.