[BIGWHEEL450]

I read bag3813 thread and I am having the same issue with 4th gear Won't shift in to 4th or reeves way up and slams in to gear or down shifts to 3rd I have been running IDP extream tune which I have had some shifting issues with but the last three weeks I have had it in IDP tow tune towing my backhoe (18000#),spoil vac (14000#full), and trencher (12000#) Yesterday it started slipping and it has progressively gotten worse. I think I will be able to get it warranted I don't know yet if I will have to take the truck back to stock. I do have a question about the updates I have not done any of them, should I have them all done while it is in the shop and if i do will my tuner and IDP tunes still work Also does anyone make stouter parts I can have installed in the tranny. The truck is a job1 02/07 with 36,000 miles I bought it used in February with 24,000 miles. I thought the 450 would be heavy duty enough but I might have been mistaken I should just stick with my 4700 Internationals and just buy a another runaround 3/4 ton for light towing. Does anyone think it is the towing lately or the extream tune? Any input or comments will be appreciated thanks