My printer (brand new brother) keeps jamming when I try to print a large package (100 pages legal and letter) It does not jam when I use foxit but I can't get foxit to pull from both trays so I need to use Adobe.
I'd be very surprised if the software (which should be using the same print driver) is causing a jam. But who knows? I would take careful note as to what printer/driver is being used by Foxit, and then ensure Reader/Acrobat is using the exact same one. I have seen multiple listings of the same printer that behave differently over the years. And I would dig deep into the printer settings to see if you can find a place to turn control the pulling from your paper trays.
A possible solution might also be to print to just one paper size, and enable the fit to page feature, forcing the legal pages to fit to Letter/A4 pages - but I know that is not always a viable solution.
It kept jamming on the same page of the package. Brother replaced the printer and the new one keeps jamming on the same page. Does that sound like it's Acrobat? I have a Macbook pro.
Jamming is a physical issue with the paper traveling through the printer. How can Acrobat do that?
One thing to look at is your statement that you "can't get Foxit to pull from both trays". Perhaps it is the second tray that Foxit can't get to that is the problem? Try another program, such as Word, and print to the other tray.
As David mentioned, a physical print jam would not be because of adobe. Is the print jam happening because the paper is physically getting stuck somewhere in your printer? or are you getting an error code that says there is a error in something like spooling?