diff --git a/lib/6to5/transformation/transformers/es6/tail-call.js b/lib/6to5/transformation/transformers/es6/tail-call.js
index b9af8e209a..c54259135c 100644
--- a/lib/6to5/transformation/transformers/es6/tail-call.js
+++ b/lib/6to5/transformation/transformers/es6/tail-call.js
@@ -210,6 +210,4 @@ exports.FunctionExpression = function (node, parent, scope) {
     ]), shouldContinueId),
     t.returnStatement(resultId)
   ]);
-
-  node.params = [];
 };
diff --git a/lib/6to5/transformation/transformers/index.js b/lib/6to5/transformation/transformers/index.js
index ab5aff2ee9..ffd23e19bb 100644
--- a/lib/6to5/transformation/transformers/index.js
+++ b/lib/6to5/transformation/transformers/index.js
@@ -52,13 +52,13 @@ module.exports = {
   // needs to be after `es6.blockScoping` due to needing `letReferences` set on blocks
   "es6.blockScopingTDZ":                   require("./es6/block-scoping-tdz"),
 
-  "es6.tailCall":                          require("./es6/tail-call"),
-
   "es6.parameters.default":                require("./es6/parameters.default"),
   "es6.parameters.rest":                   require("./es6/parameters.rest"),
 
   "es6.destructuring":                     require("./es6/destructuring"),
 
+  "es6.tailCall":                          require("./es6/tail-call"),
+
   regenerator:                             require("./other/regenerator"),
 
   // needs to be after `regenerator` due to needing `regeneratorRuntime` references
diff --git a/test/fixtures/transformation/es6-tail-call/call-apply/expected.js b/test/fixtures/transformation/es6-tail-call/call-apply/expected.js
index 806974a174..56732fe861 100644
--- a/test/fixtures/transformation/es6-tail-call/call-apply/expected.js
+++ b/test/fixtures/transformation/es6-tail-call/call-apply/expected.js
@@ -1,6 +1,6 @@
 "use strict";
 
-(function f() {
+(function f(n) {
   var _arguments = arguments,
       _this = this,
       _shouldContinue,
diff --git a/test/fixtures/transformation/es6-tail-call/expressions/expected.js b/test/fixtures/transformation/es6-tail-call/expressions/expected.js
index fe2b8c5d97..b00fec1a5b 100644
--- a/test/fixtures/transformation/es6-tail-call/expressions/expected.js
+++ b/test/fixtures/transformation/es6-tail-call/expressions/expected.js
@@ -1,6 +1,6 @@
 "use strict";
 
-(function f() {
+(function f(n) {
   var _arguments = arguments,
       _this = this,
       _shouldContinue,
diff --git a/test/fixtures/transformation/es6-tail-call/recursion/actual.js b/test/fixtures/transformation/es6-tail-call/recursion/actual.js
index 9d2b656565..67de2e6943 100644
--- a/test/fixtures/transformation/es6-tail-call/recursion/actual.js
+++ b/test/fixtures/transformation/es6-tail-call/recursion/actual.js
@@ -1,4 +1,4 @@
-(function f(n, /* should be undefined after first pass */ m) {
+(function f(n = getDefaultValue(), /* should be undefined after first pass */ m) {
   if (n <= 0) {
     return "foo";
   }
diff --git a/test/fixtures/transformation/es6-tail-call/recursion/exec.js b/test/fixtures/transformation/es6-tail-call/recursion/exec.js
new file mode 100644
index 0000000000..a3098d4c24
--- /dev/null
+++ b/test/fixtures/transformation/es6-tail-call/recursion/exec.js
@@ -0,0 +1,9 @@
+var timeLimit = Date.now() + 1000;
+
+assert.equal((function f(n) {
+  assert.operator(Date.now(), '<', timeLimit, "Timeout");
+  if (n <= 0) {
+    return "foo";
+  }
+  return f(n - 1);
+})(1e6), "foo");
diff --git a/test/fixtures/transformation/es6-tail-call/recursion/expected.js b/test/fixtures/transformation/es6-tail-call/recursion/expected.js
index d2831ed807..1f5e8fcaf5 100644
--- a/test/fixtures/transformation/es6-tail-call/recursion/expected.js
+++ b/test/fixtures/transformation/es6-tail-call/recursion/expected.js
@@ -1,13 +1,14 @@
 "use strict";
 
-(function f() {
+(function f(_x, /* should be undefined after first pass */m) {
   var _arguments = arguments,
       _this = this,
       _shouldContinue,
       _result;
   do {
     _shouldContinue = false;
-    _result = (function (n, /* should be undefined after first pass */m) {
+    _result = (function (_x, m) {
+      var n = arguments[0] === undefined ? getDefaultValue() : arguments[0];
       if (n <= 0) {
         return "foo";
       }
diff --git a/test/fixtures/transformation/es6-tail-call/try-catch/expected.js b/test/fixtures/transformation/es6-tail-call/try-catch/expected.js
index 0896197b35..cc8434fd01 100644
--- a/test/fixtures/transformation/es6-tail-call/try-catch/expected.js
+++ b/test/fixtures/transformation/es6-tail-call/try-catch/expected.js
@@ -9,7 +9,7 @@
   } catch (e) {}
 })(1000000) === "foo";
 
-(function f() {
+(function f(n) {
   var _arguments = arguments,
       _this = this,
       _shouldContinue,
@@ -43,7 +43,7 @@
   } finally {}
 })(1000000) === "foo";
 
-(function f() {
+(function f(n) {
   var _arguments = arguments,
       _this = this,
       _shouldContinue,