diff --git a/lib/ransack/helpers/form_helper.rb b/lib/ransack/helpers/form_helper.rb
index 421c43064..0f69895a4 100644
--- a/lib/ransack/helpers/form_helper.rb
+++ b/lib/ransack/helpers/form_helper.rb
@@ -83,7 +83,7 @@ def sort_link(search, attribute, *args)
         sort_params = []
 
         Array(sort_fields).each do |sort_field|
-          attr_name, new_dir = sort_field.to_s.downcase.split(/\s+/)
+          attr_name, new_dir = sort_field.to_s.split(/\s+/)
           current_dir = nil
 
           # if the user didn't specify the sort direction, detect the previous
diff --git a/spec/ransack/helpers/form_helper_spec.rb b/spec/ransack/helpers/form_helper_spec.rb
index ffa0b4b30..ec9fa5aa7 100644
--- a/spec/ransack/helpers/form_helper_spec.rb
+++ b/spec/ransack/helpers/form_helper_spec.rb
@@ -7,6 +7,7 @@ module Helpers
       router = ActionDispatch::Routing::RouteSet.new
       router.draw do
         resources :people
+        resources :notes
         get ':controller(/:action(/:id(.:format)))'
       end
 
@@ -266,6 +267,25 @@ module Helpers
           should match /Full Name/
         }
       end
+
+      describe "#sort_link on polymorphic association should preserves association model name case" do
+        subject { @controller.view_context
+          .sort_link([:main_app, Note.search()],
+            :notable_of_Person_type_name, "Notable", :controller => 'notes')
+          }
+        it {
+          should match(
+            if ActiveRecord::VERSION::STRING =~ /^3\.[1-2]\./
+              /notes\?q%5Bs%5D=notable_of_Person_type_name\+asc/
+            else
+              /notes\?q(%5B|\[)s(%5D|\])=notable_of_Person_type_name\+asc/
+            end
+            )
+          }
+        it { should match /sort_link/ }
+        it { should match /Notable/ }
+      end
+
       context 'view has existing parameters' do
         before do
           @controller.view_context.params.merge!({ :exist => 'existing' })