First, I'm sure this has been covered more than once but the google search brings the suck.
Helping a buddy build a yota. He is running 33's, manual tranny, and looking into a 4.70 tcase gear. With this setup, the final drive ratio calcs out to about 76.
Since I have a xj with and auto and 5:13's, and only two shakedown runs under my beltshaking, I have no concept of how this kind of final drive performs in manual gearbox yota.
This truck is being built to be a mild wheeler - Fordyce is the toughest trail it will see, at least for a long time.
So the question comes down to this - is it low enough to have fun on the 'con/fordyce?
I believe you are talking about crawl ratio not final drive ratio. try searching that.
My experience is I started with stock 2.28 t-case. I took that through pritchett canyon in moab the day after it snowed. The trail is rated a 5 (most difficult by moab ratings). I say that to illustrate that crawler gears are not required, although I haven't done the trails your talking about.
Now I have a dual case. 4.7 rear and 2.28 crawler. I honestly use the 4.7s on many obstacles that cannot be "crawled" I use the 2.28 and 4.7 to crawl up on something to get a feel before I give it a go. I use both t-cases on virtually every trail in low low at some point. Pritchett is now easier with the dual case setup. it gives you more control/finesse
Your buddy will appreciate the 4.7 kit. 76:1 isn't bad but i my opinion its still a bit high for a manual truck. From experience it's really nice to have at least 100:1 manual or 60:1 auto. This is "just enough" crawl to get through some of the toughest shit around with a full body rig.
With only a 76:1 crawl ratio with a 4.7 Tcase I'm guessing your buddy has stock 4.10 R&P gears. Swapping to 4.88's in the diffs will bring the ratio up to 90:1 which is a very good crawl ratio for the 'Con and Fordyce.
crawl ratio is when the trans is in first, and tcase is in selected gear (usually low)
final drive is usually important for people you end up on the street- it is when the trans is in its highest gear (usually drive 1:1 or overdrive .75:1) and the tcase is usually in high (1:1)
one important detail is that crawl ratios are directly related to tire size. A 100:1 ratio with 42 tires isn't the same perception as a 100:1 crawl ration with 35" tires, due to the difference in tire circumfrence. The larger the tire, the higher crawl ration you will want.
My rig is an auto with a ~54:1 crawl and 39.5" tires. I would like to be about 65 or 70:1, but it isn't in the budget...
then there is also the agruement between ruinning a doubler or just low tcase gears to achieve the ratio you want. Personally I like the doubler approach better, simply becuase you will have something between the low 54:1 and the 1:1. For instance my setup yeilds 54:1, 27:1, 20:1 and 1:1. You only get those options with a doubler or atlas 4 speed.
Your buddy will appreciate the 4.7 kit. 76:1 isn't bad but i my opinion its still a bit high for a manual truck. From experience it's really nice to have at least 100:1 manual or 60:1 auto. This is "just enough" crawl to get through some of the toughest shit around with a full body rig.
I think 76:1 is quite low for being on 33's. I'm running a 54:1 crawl ratio and while it's occasionally a bit higher than I like, it gets the job done. However, my setup is quite different than the one in question, I can idle at 400rpms and have pleanty of torque to boot.
I personally think people get way to hung up on crawl ratio, tire diameter is equally important, and being on 33's that's more than enough gear.
My truck came stock with 59:1, and with 35" rubber it crawled farily nice, the huge gap from 1rst to 2nd got annoying, that and, reverse was so low I lacked any wheelspeed.
Putting a doubler in mine brought it to 123:1, which seems to work out nicely with 38's. However, the biggest things I gained was 2nd and 3rd double low are sweeeeetttttt ratios, and the option of a higher low range, for more wheelspeed in reverse.
I am at 81:1 with a GM 2.5 and 34s. It seems to be enough for my samurai.
I understand the toy weighs more, But I think that the 22RE has more power realistically.
I think that I would want a little more than 76:1. I think that a doubler would be the way to go.
For me, I ran a 5.0LTBI V8, SM465(6.5), stock FJ40 tcase(~2.0), and 4.11 gears with 35" tires. Crawl ratio was about 53 to 1. There were a couple instances where I really wanted/needed lower. Motor had no problem idling down to 400-500 rpm.
76 to 1 with 33s is going to be good for 99% of the stuff. With 33s, I would think ground clearance would be more of an issue than gearing. Gearing does compensate for a lot of stuff though.
Next mod would be bigger tires and lower diff gears, then get the doubler after that.
Well, I haven't run Fordyce but 76:1 is a very good ratio for 33 inch tires. Most of the guys with higher ratios have much larger rubber.
To me the path here is really clear. Wheel the thing, get some experience, and use that to guide the direction of the buildup. I'd guess that with 33's it's still a mildly built rig and there are things he'll want to address long before the crawl ratio.
To me the path here is really clear. Wheel the thing, get some experience, and use that to guide the direction of the buildup. I'd guess that with 33's it's still a mildly built rig and there are things he'll want to address long before the crawl ratio.
Well, at this point... I think we are ready to tackle crawl ratio. It will stay on 33's most likely for the next two years. So, at this point Chevy's and shackles are taken care of in the rear, All Pro Springs and a drop hangar were recently slipped in up front. High steer should be taken care of this weekend. All that is left to get it wheelable is gears and a locker. While ideally he should be gearing the axles as well as the tcase, he is not. He thinks he can hang with his 4.10's for the time being. Certaintly not ideal, but doable. Also, he came across a little more money so it looks like it will be dual cases first as opposed to the 4.7 gear. In low/low this should give an 84:1 ratio, which sounds like it will do the trick nicely.
if you are looking to do just the gears or the dual cases, I would recomend the dual cases first, especially for a mild wheeler. I use my stock low range quite a bit still, and my friend with just the gears seems to have trouble finding the right gear sometimes.
I run @ over 90 to 1 with 37's // sm420 //D300 in a CJ & really like it at Fordyce & the Con. However, for hillclimbing my granny is too low & 1st gear is too high. I would still rather be out in the woods wheeling than on the computer bitchin about it.
My buddy runs at 70:1 in a CJ with 35's//T98//D300. He says he is a little fast, would like to be slower. His rig works very well on Fordyce & the con. His granny-1st gear split really sucks. He pretty much runs the con in granny because his 1st gear is too fast.
It would be real nice to have a doubler for the gearing options for hillclimbing, crawlin, or cruising the bouncy stuff over the trails.
htek what part of the world are you in? I found that from the Mississippi west low is 150/1 or lower where as in the east 80/1 is more the definition of "crawl" .
JH
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