Transmission seems to be sluggish andvibrates when moving between gears at about 40-45 and 60-65. This has been the case for several years now, but recently towed a U-Haul trialor and it seems to have worsened and at times makes a noise for say 10-15 seonds that sound and feels like y9ou are driving on a rumbe strip on the highway shoulder. Does this sound like complete transmission issue could it need some minor adjustments?