Quick question... I have a 2000 CTD 2500 with the towing package and 3.55 gears. I am towing a 8,000 lb trailer and having difficulty with hills in overdrive. The rpm without OD is about 2200 at 60 and about 1800 at 70. My problem is between the 60 and 70 range. My RPM's without overdrive is 2600 at 65 (too high) and down to 1700 RPM with over drive at about 65 (too low rpm). I am thinking of having a set of 4.10 gears installed to help out with the towing but am afraid that the RPM range with overdrive will be about 2200 at 65. Thoughts and advise? Don't want to kill the CTD or tranny by lugging it down, and at the same time hate to loose the 21 MPG with the 3.55 gears. Thanks.