I posted a response to another thread earlier, but I think that tread is
dead so I'll repost here:

Someone said something about having one of those Pennzoil drive in places
fill your transmission fluid is a bad idea. Something about them using the
wrong kind and it can cause your truck to not want to go into over drive.
Can someone elaborate on this? I have a Dakota that has that issue every now
and then. If this is the issue what do I need to do?

Thanks
-Matt