diff --git a/src/Carbon/Carbon.php b/src/Carbon/Carbon.php
index 4068ae811d..2d58016e9b 100644
--- a/src/Carbon/Carbon.php
+++ b/src/Carbon/Carbon.php
@@ -2801,9 +2801,13 @@ public function diffInMinutes(self $dt = null, $abs = true)
     public function diffInSeconds(self $dt = null, $abs = true)
     {
         $dt = $dt ?: static::now($this->getTimezone());
-        $value = $dt->getTimestamp() - $this->getTimestamp();
+        $diff = $this->diff($dt);
+        $value = $diff->days * static::HOURS_PER_DAY * static::MINUTES_PER_HOUR * static::SECONDS_PER_MINUTE +
+            $diff->h * static::MINUTES_PER_HOUR * static::SECONDS_PER_MINUTE +
+            $diff->i * static::SECONDS_PER_MINUTE +
+            $diff->s;
 
-        return $abs ? abs($value) : $value;
+        return $abs || !$diff->invert ? $value : -$value;
     }
 
     /**
@@ -3383,27 +3387,6 @@ public function isBirthday($dt = null)
         return $this->isSameAs('md', $dt);
     }
 
-    /**
-     * Consider the timezone when modifying the instance.
-     *
-     * @param string $modify
-     *
-     * @return static
-     */
-    public function modify($modify)
-    {
-        if ($this->local) {
-            return parent::modify($modify);
-        }
-
-        $timezone = $this->getTimezone();
-        $this->setTimezone('UTC');
-        $instance = parent::modify($modify);
-        $this->setTimezone($timezone);
-
-        return $instance;
-    }
-
     /**
      * Return a serialized string of the instance.
      *
diff --git a/tests/Carbon/ModifyNearDSTChangeTest.php b/tests/Carbon/ModifyNearDSTChangeTest.php
new file mode 100644
index 0000000000..f28561b8fe
--- /dev/null
+++ b/tests/Carbon/ModifyNearDSTChangeTest.php
@@ -0,0 +1,66 @@
+<?php
+
+/*
+ * This file is part of the Carbon package.
+ *
+ * (c) Brian Nesbitt <brian@nesbot.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Tests\Carbon;
+
+use Carbon\Carbon;
+use Tests\AbstractTestCase;
+
+class ModifyNearDSTChangeTest extends AbstractTestCase
+{
+    /**
+     * Tests transition through DST change hour in non default timezone
+     *
+     * @dataProvider getTransitionTests
+     */
+    public function testTransitionInNonDefaultTimezone($dateString, $addHours, $expected)
+    {
+        date_default_timezone_set('Europe/london');
+        $date = Carbon::parse($dateString, 'America/New_York');
+        $date->addHours($addHours);
+        $this->assertSame($expected, $date->format('c'));
+    }
+
+    /**
+     * Tests transition through DST change hour in default timezone
+     *
+     * @dataProvider getTransitionTests
+     */
+    public function testTransitionInDefaultTimezone($dateString, $addHours, $expected)
+    {
+        date_default_timezone_set('America/New_York');
+        $date = Carbon::parse($dateString, 'America/New_York');
+        $date->addHours($addHours);
+        $this->assertSame($expected, $date->format('c'));
+    }
+
+    public function getTransitionTests()
+    {
+
+        // arguments:
+        // - Date string to Carbon::parse in America/New_York.
+        // - Hours to add
+        // - Resulting string in 'c' format
+        $tests = array(
+            // testForwardTransition
+            // When standard time was about to reach 2010-03-14T02:00:00-05:00 clocks were turned forward 1 hour to
+            // 2010-03-14T03:00:00-04:00 local daylight time instead
+            array('2010-03-14T00:00:00', 24, '2010-03-15T00:00:00-04:00'),
+
+            // testBackwardTransition
+            // When local daylight time was about to reach 2010-11-07T02:00:00-04:00 clocks were turned backward 1 hour
+            // to 2010-11-07T01:00:00-05:00 local standard time instead
+            array('2010-11-07T00:00:00', 24, '2010-11-08T00:00:00-05:00'),
+        );
+
+        return $tests;
+    }
+}
diff --git a/tests/Carbon/ModifyTest.php b/tests/Carbon/ModifyTest.php
index 179590c692..aa86172433 100644
--- a/tests/Carbon/ModifyTest.php
+++ b/tests/Carbon/ModifyTest.php
@@ -30,5 +30,8 @@ public function testTimezoneModify()
         $b = $a->copy();
         $b->addHours(24);
         $this->assertSame(24, $a->diffInHours($b));
+        $this->assertSame(24, $a->diffInHours($b, false));
+        $this->assertSame(24, $b->diffInHours($a));
+        $this->assertSame(-24, $b->diffInHours($a, false));
     }
 }