I am running approx a 33.7” tire now (285/70/18), and after having to replace a transmission recently, I have seriously considered going to different gears, but after much thought, at least for now, I am staying with my 3.73s.
Here is why.
Certainly I suffer a bit on takeoff from stops or at slow speeds, and often I wish I had a 4.30 or 4.56 setup, as I have to be patient and not overload my trans before TC lockup.
At higher speeds when I come to a grade, I don’t wnt to be in my overdrive gears (5 or 6), and 4th gear is the single strongest gear as it is direct drive.
I can hold speeds up to about 63-65mph without the engine revving to high (less than 2200rpm at most effective uphill speeds).
Were I to go to a lower diff gear, my takeoff would be under less strain on the clutches, and overall is easier on the trans.
At hwy speeds (55-70j I would be compelled to run in overdrive gears, or be forced to drop to 4th to get out of the overdrive clutches which are notoriousl weak v. the simple smart decision to attack high load situations (grades) in 4th.
Were I to run 4.56 with my tire size, I would be compelled to climb the same grade 10mph lower than with the 3.73s.
All in all, a give and take, I am pretty happy giving slower takeoff and having to be smart with throttle on low line pressure/ no tc lockup situations (traffic/ stop and go city) and enjoy the benefits of having good speeds in a trusty gear on grades.
The engine has all the power would want. The transmission being the weak link.
I am running a Revmax550 with a revmax stage5 lo-stall TC, and a billet input shaft over Revmax’s TCM tune.
Engine is EFI live Anarchy tune on tow setting.
I tow. 16k 5er, and a 10k car hauler/race trailer.