Gears opinions? (1 Viewer)

[Tennessee80]

There are loads of threads on mud about 40s and what diff gears/transfer case gears to get, and it also depends on what type of wheeling you are doing and how much street/trail the truck sees. My rig is SOA on 35's with the original F.5 and 4 speed. It drives well (relatively) on the street, and I don't plan on making it a trailer queen. For events that are a reasonable distance, I plan on driving the 40 with my camper. I want the 40 to be capable, not into crazy hard core stuff, but I do enjoy some challenges. I would just like to see if anyone else has my same base setup, and if they regeared or got transfer case gears like Orion...

Just in the planning stages...

thanks,

Joel

 

[pb4ugo]

If you're happy with you're hi range gears on the street now , then I'd probably look at either a different tcase with a lower low range ratio or maybe a trans with a lower 1st gear or a combination of both. There are many options.

I have made major driveline swaps in the past. Anymore I start with what tranny and tcase options that available and the various tcase low range gears swaps. Then look at the various individual tranny gear ratios of each tranny(1st,2nd,3rd,etc) you are considering and compare them to you're ratios you are now running. I do it this way because you know where youre current setup is good and is lacking. Find a good rpm calculator on the net to factor in you're tire size and then figure in the lower range ratios and compare those too. Now you might also check how different diff ratios effect rpms too. I usually make a chart for how each driveline computes out. Don't forget there are 5 speeds as an option too. Then look at the cost and and the amount of work is involved. Remember most GM tranny will not shift as nice as a stk L/C 4 speed.

Going from 4.11's to say 4.88's is not much of a change imo. This was my 1st gearing change after running 4.ll's and 33's for 10yrs or so. Because of the long seat time with 4.11's the upgrade was very helpfull, but I quickly wanted a lower gear. My 1st fj40 is set up for more trail use but is able to run60 or 65 on the highway and crawl with a 85:1 ratio. It does have a sbc though, so the higher rpms are OK. It runs 35" boggers. My 2nd 40 is set up more for street sbc,nv4500,stk tcase, and 3.70 diffs and 33s. I figure it will be approx 1900 rpms at 60mph and have a decent low range. I'm currently doing some upgrades on it so i havent driven it with the 3.70's yet.

Look for the best option for the money and the amount of work. Remember 4th gear is usually 1:1 among all 4 speeds.

 

[Tennessee80]

Good advice, dude! I am going to a few trips this spring/summer and will wheel it as it sits now, then decide what I want to achieve after that first "diagnosis" from the trail. Low range engine braking in 1st gear downhill will be an initial indicator to how I probably need lower transfer case gears, I bet. Even though I have 4 wheel disc brakes, being able to stay off the brakes is huge.

 

[White Stripe]

Good advice, dude! I am going to a few trips this spring/summer and will wheel it as it sits now, then decide what I want to achieve after that first "diagnosis" from the trail. Low range engine braking in 1st gear downhill will be an initial indicator to how I probably need lower transfer case gears, I bet. Even though I have 4 wheel disc brakes, being able to stay off the brakes is huge.

I have 4.11s and 35s with a sm465 and stock tcase. I have an Orion sitting waiting for me to put it together. I like my cruising rpm at highway speed. I need lower gears for offroad though, and that is why i bought the orion. I want to have at least 100:1 in 1st gear low range. With the sm465 alone I am at about 61:1 which is low enough for most situations, but when things get really technical its not low enough. Thus why I got the orion which should put me around 107:1 with the sm465s low first gear.

 

[Tennessee80]

Do you have the SM465 mated to a F or 2f?

thanks

 

[Tigerstripe40]

I've been running SM420, '4 speed' t-case (1.9:1) , and 4.88's and 35's for 5 years now.
Overall Crawl ratio is 66:1 and I rarely feel like I need more.

On the highway, I can do 65-70mph, but the engine is turning pretty high rpms.
I drive my truck to/from the trail. I've often considered an overdrive, but for the costs involved for the various options (H55, NV4500, Ranger OD), a tandem axle flatbed trailer would be a better use of my $$$.

 

[Tennessee80]

Yeah, with a 40 that naturally isn't as highway friendly with larger tires, gears, etc, it's no wonder why they are on trailers going to events. A lot of wagons drive to trails for sure. I'll see where I'm at this spring and then decide if I want to do gears or tcase gears or both? @ToyotaTrailTeam's 80 has 5.29 and crawler gears and it's a joy to drive on trails

 

[1911]

I drive mine cross-country to get to good trails, and love the combination I currently have:

33" tires, 3.70 diffs, 4:1 Orion, H41 transmission (with its 5.3:1 1st gear).

Starts from full stop easily, pulls 65 mph at 2450 RPM on the highway, 78:1 crawl ratio in low-range 1st gear when needed on the trail. Can do most anything in the Moab area with this gearing.