I modified per your recommendation:

#!/usr/bin/perl -w
use strict;
use Expect;

my $timeout = '5';
my $username = 'luser';
my $newpass = 'luser';
my $oldpass = 'n3wp@ss!';

open(HOSTS,"hosts.txt")
            or die "Error while opening file:$!\n";
            chomp( my @hosts = <HOSTS> );
close(HOSTS)
            or die "Error while closing file:$!\n";
my $exp;
foreach (@hosts) { 
    $exp = Expect->spawn("ssh -l $username $_")
    or die "Cannot spawn ssh: $!\n";;
my $spawn_ok;
#$exp->exp_internal(1);
                  do_exp ($timeout, 'password', $oldpass);
                  do_exp ($timeout, "$username\n", "passwd");
                  do_exp ($timeout, 'password:', $oldpass);
                  do_exp ($timeout, 'password:', $newpass);
                  do_exp ($timeout, 'password:', $newpass);
          }

          sub do_exp {
                  my ($_timeout, $_lookfor, $_send) = @_;
                  if ($exp->expect($_timeout,'-re',$_lookfor)) {
                          $exp->send($_send);
                  } else {
                          die "Timeout waiting for $_lookfor.\n";
                  }
          }
[download]

but am still having problems.
I show the output with verbose debugging turned on below:

Starting EXPECT pattern matching...
    Expect::expect('Expect=GLOB(0x835f7e0)', 5, '-re', 'password') cal
+led at ./example.pl line 30
    main::do_exp(5, 'password', 'n3wp@ss!') called at ./example.pl lin
+e 21
spawn id(3): list of patterns:
  #1: -re `password'


spawn id(3): Does `'
match:
  pattern #1: -re `password'? No.

luser@10.10.10.39's password: 
spawn id(3): Does `luser@10.10.10.39\'s password: '
match:
  pattern #1: -re `password'? YES!!
    Before match string: `luser@10.10.10.39\'s '
    Match string: `password'
    After match string: `: '
    Matchlist: ()
Sending 'n3wp@ss!' to spawn id(3)
    Expect::print('Expect=GLOB(0x835f7e0)', 'n3wp@ss!') called at ./ex
+ample.pl line 30
    main::do_exp(5, 'password', 'n3wp@ss!') called at ./example.pl lin
+e 21
Starting EXPECT pattern matching...
    Expect::expect('Expect=GLOB(0x835f7e0)', 5, '-re', 'luser^J') call
+ed at ./example.pl line 30
    main::do_exp(5, 'luser^J', 'passwd') called at ./example.pl line 2
+2
spawn id(3): list of patterns:
  #1: -re `luser\n'


spawn id(3): Does `: '
match:
  pattern #1: -re `luser\n'? No.

n3wp@ss!
spawn id(3): Does `: n3wp@ss!'
match:
  pattern #1: -re `luser\n'? No.

Timeout waiting for luser
[download]

Without verbose debugging:

luser@10.10.10.39's password: n3wp@ss!Timeout waiting for luser
.
[download]

Thanks again for the assist!