diff --git a/src/htmx.js b/src/htmx.js
index 5b7795f5c..b6b761981 100644
--- a/src/htmx.js
+++ b/src/htmx.js
@@ -3302,8 +3302,7 @@ return (function () {
                 });
             });
             triggerEvent(elt, 'htmx:beforeSend', responseInfo);
-            var userSetContentType = (etc.headers && etc.headers['Content-Type']);
-            var params = useUrlParams ? null : !userSetContentType ? encodeParamsForBody(xhr, elt, filteredParameters) : etc.values;
+            var params = useUrlParams ? null : encodeParamsForBody(xhr, elt, filteredParameters);
             xhr.send(params);
             return promise;
         }
diff --git a/test/core/api.js b/test/core/api.js
index 916ae3a44..dd88695be 100644
--- a/test/core/api.js
+++ b/test/core/api.js
@@ -272,9 +272,9 @@ describe("Core htmx API test", function(){
     it('ajax api Content-Type header override to application/json', function(){
 
         this.server.respondWith("POST", "/test", function (xhr) {
+            var params = getParameters(xhr);
             xhr.requestHeaders['Content-Type'].should.equal('application/json;charset=utf-8');
-            const requestBody = JSON.parse(xhr.requestBody);
-            chai.expect(requestBody.grug).to.be.equal("brain");
+            params['i1'].should.equal("test");
             xhr.respond(200, {}, "Clicked!");
         });
 
@@ -285,7 +285,7 @@ describe("Core htmx API test", function(){
                 headers: {
                     'Content-Type': 'application/json'
                 },
-                values: '{"grug":"brain"}'
+                values:{i1: 'test'}
         })
 
         this.server.respond();