1967 Cougar transmission problems

I've got a 67 cougar, with a hi-po 289 in it, and i'm having some troubles with it shifting. It's a 3 speed automatic transmission, and it hesitates to shift gears. Especially when the cars not warmed up. I don't have a rpm guage, but the rpm's will keep going up, as if it doesn't want to shift. And the car has a tremendous lack of power/torque. I can shift it manually from 1st to 2nd, but when i go from second to drive, it acts like it's in nuetral, and doesn't go anywhere. Also, when i take off, and give it gas, i hear a grinding noise comming from the transmission. Any clues?

ford introduce the c4 in1964-1982.the larger version was introduce 1966 call c6
for large v8s.there for i assume you either have a c4 aluimune or c6 cast iron transmission either way will go from here.in 1969 i had a galaxy 500 with 302 bored out 289 factory.i had aluimine c4.had same problem.the forward clutch pack fiber disk wore out and the steels are rubbing together do not drive this car anymore your in trouble the only way is rebuild intermed band caused problem.shevings are in the oil you will have too replace torque converter if you have a drain plug on this unit you might be able to flush out not recomended.rebuild kits in 1972 were $64.00 bands $20.00 torque converter refurbished $100.00.intermedant band was nylon light duty replace this with heavy duty this band has caused your problem.it took me 14hours to fix my self.recomend buying automatic transmission and transaxle 3rd edition. this is a class room manual.many pictures color detail cad drawings covers all ford transmissions.great reading chek-chart publications.they have valve body and check valve locations (little rubber balls) warning do not open valve body unless your sure you know what your doing if these check valves fall out your in trouble.band adjustment are touchey has to be on the money or your work will be in vane. trust me been their done that call when you get to this point 919-934-8513 i will tell you how to do this.this transmission is so easy to rebuild a cave man can do it.good luck.