Anyone tried syn in trans to 'fix' TC issue?

[dayne66]

i had an '03 Envoy...the trans started shifting hard,hesitating,slow downshifts... generally not right..light came on briefly a few times...dealer was useless....I had filter changed and flushed..put in Amsoil....worked like new for the next 30k until lease was up.

 

[tjkj2002]

i had an '03 Envoy...the trans started shifting hard,hesitating,slow downshifts... generally not right..light came on briefly a few times...dealer was useless....I had filter changed and flushed..put in Amsoil....worked like new for the next 30k until lease was up.

The OEM tarnny fluid in your KJ is ATF+4,a full synthetic ****** fluid,but Amsoil ATF is good also.