Jayco254 wrote:
I'd keep asking around. In the 2001 5.9 liter Durango I had before I bought my Expedition ( it was also one of the reasons I bought the Expedition ) I went from 3:55s to 3:92s against the advice of the mechanic that installed them, turned out he was right I couldn't tell any difference to speak of, just the waste of a lot of money. The gear ratios are just to close together to make much difference.
I went from 3.55 to 3.90 on my 97 Dodge conv. van with the 5.9L. it was a night and day difference! I wanted to go to 4.10, but I settled for the 3.90`s. glad I did. big difference in towing performance!
I also went from 3.73 to 4.30 in my X and it too was a night and day difference. regearing with the proper gears is the best mod for towing performance.