Gear Choice for new rears

[John N]

I'm looking for some input for this decision. I'm building a new set of rears, Scout (58") width 44's. I have a 999TF (1 to 1 high gear), stock 300 transfer case, 360 AMC (basicly stock), currently with 33's (at the most, maybe 35's latter). This is not a daily driver, but is about 50/50 street trail, there isn't much for rock crawling here in Va. I trailer to most offroad runs I go to, I don't like to worry about breaking and figuring out how to get home. These rears will have ARB's. So the question is what ratio to go with, I'm considering 4.10, 4.27, or 4.56? Thanks for the help.
Hey Matt, what up with the "secret project"?
John N

 

[mulescj8]

with a V8 and 33" I'd think that the 4:10s would be pretty good all round gear,but if you do more trails than street and trailer to rides,I'd go with the 4:56s since your thinking of going to 35s at a latter date.My motto is you can never be to low on the trail. JC Oliver

 

[Dennis Chaffin]

The question is how fast do want to go on the highway and how hard do you want to rap the motor? the 33/4.10 combo works well for off road and at 70 mph is 3000 rpm. I just put in 4.56 with 35's, 65 mph is about 3000 rpm I only drove it about 20 miles so I not sure how it'l be. Always good to be low geared.

 

[bob ackley]

I am running the "forgotten" 4.27 ratio. I call it that because you can't get that in the M20, only in the D44, so many CJ owner's don't have experience with it.
I have 33's, and a 5 speed. I am really happy with it both off-road, and on the highway.
Anyway, best advice is to actually measure your tires, most 33's are NOT, then find one of the gear ratio calculators flying about on the web.
Plug the different ratios in, and see what you come up with....

 

[ROK HUGR jefe]

John,
With the TF999, AMC 360, and 33's or 35's, I would go with the 4.10's. You will have plenty of creeping ability with the auto/D300, but will still be able to keep up on the highway, if need be. The larger the displacement of your engine, the taller gears you can get away with off-road. The 360 puts out buttloads of torque down low. With an auto, you can multiply the torque by about 2x because of the slippage of the torque converter, to get the 'feels like' final drive in low/low. If you had an actual creep ratio of 40:1 with your set up, with the auto it will seem like 80:1 in creep compared to a manual. The 4.10 rg&p has a larger pinion than either the 4.27 or 4.56, making it stronger behind your 360. Also because of where you live, you don't need the extreme reduction like us western rock crawlers do. You need wheel speed in mud and for those ledges. Just install a big trans oil cooler. The thing is, you will notice almost no difference between say 4.10 and 4.27(if you could use it) in low low, but will notice a bigger difference on the street and, even though you're trailering now, you will have the OPTION of staying up with traffic on the intertstate, if you decide to drive to a trail, with 4.10's. If you are sure you will never need highway gearing under any circumstances, go with 4.56 or even 4.88's (which I hear are available, on-and-off, for the D30/AMC20).
regards, as always, jefe

 

[John N]

Thanks for the answers guys. John N