i've decided to upgrade my trail capable cj7 to full rock crawling duty. i just picked up a wag' 44 front today. still need a rear to match width. i have no definite plan of what all i'm going to do other than spending a lot of money.

here's what i have: 76 cj7, carburated 360, th400, narrow trac wag' dana 44 front, dana 20 t-case, soa w/hi steer, rear traction link, wag' front leafs, yj rear leafs, d44 power lok lsd.

here's what i want: fuel delivery that will run in the rocks, low range t-case gears, rear end to match the front width(60.5 wms to wms), 4"-7" wheelbase stretch(leafs or 4 link),

tentative plan: put the power lok in the front with the deepest gears available for it, rear spool/locker, tera/klune/double t-case/atlas, 4link rear w/fox air shox/coils/coilovers or rear xj leafs/dakota leafs, projection/howell/propane/q-jet.

note: i'm not trying to build a comp rock rig, just a recreational rock crawler. i've done some research and have a good idea of what i want to do. just trying to spark some discussion about converting from trail jeep to rocks. i'm not asking how to do it but "what" others have done and how it works. any and all opinions are welcome. the budget is $5000. what would y'all do? the fab work is covered but i'll probably have to pay for gear set up. other than that, i'll be doing all the work.

any input?

What tranny?
If you are running a compound t18 or Np435 getting a klune or doubler is silly. If you are running an automatic, Klune and doublers are silly.

Look at the #s, t18 or 435...6.69x2.0x4.88 = 65:1 not bad maybe upgrading to a m300 t-case... at 2.62 = 85.54:1 way coolcrawl ratio. If you pony up to a 3.8 atlas...but go down to 4.10 axle gears...104:1 almost too slow for v8 rockcrawling. I ran a 82:1 set up with my 35" BFGs for years and loved that ratio for pretty extreme trails.
That was 304 Amc, np435,m300 and 4.56 gears.
THis set up was great because the 1st gear ratio would almost climb anything without touching the gas. But when wheel speed was needed 2nd gear was not SOOOO low that I could quickly get the tires spinning for momentum trail obstacles.

Now I run automatics and I'll never go back, the ratio does not have to be so steep because the torque converter multiplies torque. So take, 2.7:1 Common 1st gear in a TH350 or 400 x 2.62x 4.88 =35:1 combine this with a v8 and you have perfection for a 35/36" tall tire.
My new buggy has 38" tires so I'm running 5.13 gears.
The cool part about a slush box is the the wide wheel speed to engine rpm and torque ratio.
You can climb a rock obstacle in 1st gear and stop in the middle and start again without loosing any torque transfer, also if you need wheel speed a quick throttle stab and you can get the tires whipping ALL in 1st gear.

However, with an auto, if you get a 4.0 t-case kit or an 4.3 atlas, combined with 4.88...56:1 is so low (for a v8) that you can't get the tires spinning without hitting 6k rpm. Unless you have a full manual valve body (which I do NOT recomend).

I have built, driven many combos on many trails/type around the country, let me know what you think and what you plan to do. I can help.

SD
Josh

thanks for the reply, i listed the th400 tranny but you might have missed it. the t-case is one of the big ?'s. the 2.0 low range or whatever it is in the d20 is not low enough. i can get the 3.15 to 1 tera gears which would be about right. i understand your point about being geared too low not only for the reason you stated but also holding on to it with the brakes(which i don't plan to upgrade). here's where it gets complicated. i have always liked the sand. i make a 3000 mile drive every summer to go back home to the pacific nw to run the oregon dunes with my old 4x4 club. my 360 does not have enough hp to run sand in high range. 2 to 1 is great but sucks in the rocks. a klune would give me the option to keep sand low range and give me a lower option for rocks. but it may be too low. if i had a dana 300 or np231(which isn't an option with pass side drop front end) i might not be considering t-case gears. i'll probably get the tera 3.15 gears and upgrade the d20 output shaft.

the whole problem with this project is, i'm building for a style of 4 wheeling i'm not experienced in yet. i've been offroading in every type of terrain possible for the last 17 yrs except rocks. i broke my 30 front so it makes sense to upgrade to a 44. well, now i need a rear to match width. the few times i've been rock crawling has taught me enough to know i need lower t-case gears and better fuel delivery.

when it's all said and done, i want a safe reliable jeep that will run on angles, steer, and stop. ground clearance provided by 35-37 inch tires, haul 4 people, geared right for the terrain, around 100" wheelbase, and not too expensive to build. yeah, i know. it's asking a lot.

ooops, bam I see that th400 thing Now? Oh well..

Did I miss what axle gears?

I can't stand the t-case "regear" kits because they tend to break or get really noisy. With the exception of the 4-1 kit for 231's, they seem to hold up fine.

D300 case is a passenger side drop. All cj's from 80-86 had them.

Upgrade the intake/exhaust and get TBI on there and you might have the HP you need in high range?
On my 304 I went from a ford 2bbl to Holley (don't recomend)projection and on my chassis dyno went from 120 to 160 hp.
On mine I did not upgrade to a 4bbl intake, I built my own adapter from the OE 2bbl intake directly to the GM/Holley TBI pattern throttle body. Before I did the EFI I had already spun all the timing a old 304 could take into it.

I guess what I'm saying is.. tell me all the before and "want to" upgrades before you do them and I can help.

SD
Josh

there are a couple issues with axle gears too. i have 4.27's in my rear 44 right now with a power lok. i would like to use what i have for cost reasons but the 4.27 may not be low enough. especially if don't use a 4 to 1 t-case. which we'll discuss next.

the tera gearset for the d20 is about $900. i'm sure i can find a 300 for a lot less in a junkyard. do you think a 2.6 to 1 300 with low axle gears might be a good route? what are you doing with yours and what do you think i should do with mine? and why do you not recommend projection? just preference or is there a problem with it? i know the howell is a bolt on out of the box runner but the projection is much cheaper.

while we're having this discussion, i would like to figure out the axle and t-case. is there a magic number to shoot for on final ratio?

i recomend you go to an auto tranny. it will aleviate alot of your gearing issues. the tourq converter at max slip has a 2 to 1 redution. it will get you that little bit more without having to regear everything and sacrifice top end. the only draw back of low speed auto is heat. the tourq converter while slipping generates ALOT of heat compaired to a manual. luckily an extra tranny cooler and fan are ususaly quite sufficiant.

i have always had an auto, even before they were acceptable to have on a trail rig. tranny cooler and fan noted. thanks.

I have the Howell on my Jeep and even installed a kit on a 67 firebird turn the key watch it pee,intalls in less than 12 hours <img src="/forums/images/graemlins/kewl.gif" alt="" />I also run the auto cool (th400), I wanted the 700r4 how do they fit

i don't drive my jeep on the street so i've never considered the 700r4. in fact, i can't remeber the last time it was in high range. shouldn't be a tough swap though.

My new rig (tube buggy) has a 383 stroker, TH400 and a m300
axles are 14bff and 44front. 38" TSLs.
5.13:1 gears. 36:1 final, should be perfect for the 38s.
Never know a 3:1 atlas might fall from the sky?

SD