diff --git a/spring-cloud-gateway-core/src/main/java/org/springframework/cloud/gateway/filter/factory/rewrite/ModifyRequestBodyGatewayFilterFactory.java b/spring-cloud-gateway-core/src/main/java/org/springframework/cloud/gateway/filter/factory/rewrite/ModifyRequestBodyGatewayFilterFactory.java
index 2ee1f74a..5dbb9013 100644
--- a/spring-cloud-gateway-core/src/main/java/org/springframework/cloud/gateway/filter/factory/rewrite/ModifyRequestBodyGatewayFilterFactory.java
+++ b/spring-cloud-gateway-core/src/main/java/org/springframework/cloud/gateway/filter/factory/rewrite/ModifyRequestBodyGatewayFilterFactory.java
@@ -63,7 +63,9 @@ public class ModifyRequestBodyGatewayFilterFactory
 					.flatMap(o -> config.rewriteFunction.apply(exchange, o));
 
 			BodyInserter bodyInserter = BodyInserters.fromPublisher(modifiedBody, config.getOutClass());
-			CachedBodyOutputMessage outputMessage = new CachedBodyOutputMessage(exchange, exchange.getRequest().getHeaders());
+			HttpHeaders headers = new HttpHeaders();
+			headers.putAll(exchange.getRequest().getHeaders());
+			CachedBodyOutputMessage outputMessage = new CachedBodyOutputMessage(exchange, headers);
 			return bodyInserter.insert(outputMessage,  new BodyInserterContext())
 					// .log("modify_request", Level.INFO)
 					.then(Mono.defer(() -> {
@@ -71,10 +73,15 @@ public class ModifyRequestBodyGatewayFilterFactory
 								exchange.getRequest()) {
 							@Override
 							public HttpHeaders getHeaders() {
+								long contentLength = headers.getContentLength();
 								HttpHeaders httpHeaders = new HttpHeaders();
 								httpHeaders.putAll(super.getHeaders());
-								// TODO: this causes a 'HTTP/1.1 411 Length Required' on httpbin.org
-								httpHeaders.set(HttpHeaders.TRANSFER_ENCODING, "chunked");
+								if (contentLength >= 0) {
+									httpHeaders.setContentLength(contentLength);
+								} else {
+									// TODO: this causes a 'HTTP/1.1 411 Length Required' on httpbin.org
+									httpHeaders.set(HttpHeaders.TRANSFER_ENCODING, "chunked");
+								}
 								return httpHeaders;
 							}
 
diff --git a/spring-cloud-gateway-sample/src/main/java/org/springframework/cloud/gateway/sample/GatewaySampleApplication.java b/spring-cloud-gateway-sample/src/main/java/org/springframework/cloud/gateway/sample/GatewaySampleApplication.java
index 7af93e97..7901b668 100644
--- a/spring-cloud-gateway-sample/src/main/java/org/springframework/cloud/gateway/sample/GatewaySampleApplication.java
+++ b/spring-cloud-gateway-sample/src/main/java/org/springframework/cloud/gateway/sample/GatewaySampleApplication.java
@@ -72,6 +72,7 @@ public class GatewaySampleApplication {
 					.filters(f -> f.prefixPath("/httpbin")
 							//TODO: add as configuration to modifyRequestBody
 							.setRequestHeader("Content-Type", MediaType.APPLICATION_JSON_VALUE)
+							.removeRequestHeader("Content-Length")
 							.addResponseHeader("X-TestHeader", "rewrite_request")
 							.modifyRequestBody(String.class, Hello.class,
 									(exchange, s) -> {
@@ -82,9 +83,10 @@ public class GatewaySampleApplication {
 				.route("rewrite_request_upper", r -> r.host("*.rewriterequestupper.org")
 					.filters(f -> f.prefixPath("/httpbin")
 							.addResponseHeader("X-TestHeader", "rewrite_request_upper")
+							.removeRequestHeader("Content-Length")
 							.modifyRequestBody(String.class, String.class,
 									(exchange, s) -> {
-										return Mono.just(s.toUpperCase());
+										return Mono.just(s.toUpperCase()+s.toUpperCase());
 									})
 					).uri(uri)
 				)
diff --git a/spring-cloud-gateway-sample/src/test/java/org/springframework/cloud/gateway/sample/GatewaySampleApplicationTests.java b/spring-cloud-gateway-sample/src/test/java/org/springframework/cloud/gateway/sample/GatewaySampleApplicationTests.java
index 103fd2ec..fa976515 100644
--- a/spring-cloud-gateway-sample/src/test/java/org/springframework/cloud/gateway/sample/GatewaySampleApplicationTests.java
+++ b/spring-cloud-gateway-sample/src/test/java/org/springframework/cloud/gateway/sample/GatewaySampleApplicationTests.java
@@ -28,7 +28,6 @@ import com.netflix.loadbalancer.ServerList;
 import org.junit.AfterClass;
 import org.junit.Before;
 import org.junit.BeforeClass;
-import org.junit.Ignore;
 import org.junit.Test;
 import org.junit.runner.RunWith;
 
@@ -119,12 +118,11 @@ public class GatewaySampleApplicationTests {
 				.expectHeader().valueEquals("X-TestHeader", "rewrite_request_upper")
 				.expectBody(Map.class)
 				.consumeWith(result ->
-						assertThat(result.getResponseBody()).containsEntry("data", "HELLO"));
+						assertThat(result.getResponseBody()).containsEntry("data", "HELLOHELLO"));
 	}
 
 	@Test
 	@SuppressWarnings("unchecked")
-	@Ignore //FIXME 2.1.0
 	public void rewriteRequestBodyObjectWorks() {
 		webClient.post()
 				.uri("/post")