Techniques morgan in Shefford changed my 3.7 ratio to 4.11 on my 2011 4/4. Probably the best mod I have done to the car. At 70mph the car indicates an extra 300 rpm, but 5 th is useable at 40 mph and 4th useable at 30. The car is so much more “drivable” but there is always a but. When accelerating hard 1st gets to rpm limit very quickly (almost to quick)as acceleration is much improved. And as stated the diff does “ring” can be a little noisy at certain speeds. The diff noise occurs when Cruising. Apply some power it stops & letting your foot off (deceleration) it stops. I have put some sound proofing over the back part of the frame & tool tray to help. Please note I was warned that extra noise may be apparent.
