I am having a strange problem shifting my BJ74. All the fluids were replaced about a month ago. When the truck is sitting off I can pump up the clutchand it will go from very soft to very hard. After driving on the highway for a while I will have to put the truck in nutral and pump it up again or else it is very hard or imposible to get into gear. I took the truck in and we checked all over for leaks and bled the system. After that it was good for about 3 days and this started again. Any help would be muchly appreciated. thanks