cj 5 help

Baker

Baker

Well-Known Member
Joined
Mar 25, 2010
Location
Suffolk, VA
ok so i'm not real new to wheeling but i'm new to building a project i've always just had some rusted out rig beat to shit and ran it into the ground. I just bought a 78 cj 5 from "bsmith" thanks for the smoking deal man. and i've got big plans i wanna do it right but like i said i need a little input first. The plans are i'd like to put like a dana 44 or 60 up front and a 14 bolt in the rear, 4 link them full cage custom bumpers, winch and have the rear locked and front have a selectable lock so i can still drive on the road just not a dd. this cj is all stock i have an amc 360 but it came from another jeep not real sure if its rebuildable or not i'll know tomorrow but i need some input on what tranny and transfer would be best for a rig that'll spend 80 % of its time wheelin and the other 20 driving. what gears to run all that stuff. so any input would be greatly appreciated. thanks guys
 
its hard to beat a sm420/dana300 combo in a cj5.
 
when everybody talks about a twin stick dana 300 what does the twin stick mean?
 
Baker said:
when everybody talks about a twin stick dana 300 what does the twin stick mean?
Click to expand...

It means you convert it to have two shifters instead of one. The two shifters control the front and rear independently. It has several benefits.
 
is it just to control whether each axle is in 2wd or 4wd individually? i've heard of twin stick transmissions before like in race cars and stuff i'm just new to the twin stick transfer case but i've heard alot of people love em
 
a rig with axles locked front and rear can be a bear to turn in 4LO...enter the twin sticks, crawl in 2wd-Low range (rear wh.drive) until you really need 4Lo.
 
oh ok that makes sense now. thanks renegadeT. so hows that sm420/d300 for road driving? i only wanna drive the jeep on road occasionally anyways but i want to be able to go highway speeds at least 70/75 mph. any other suggestions? are they hard to come by? whats a reasonable price for them?
 
the sm420 is good for road driving, just keep good oil in it. you basically have three streetable gears, with 4th being a 1:1 ratio. but it has the lowest 1st gear available at 7.05:1, and is also the shortest heavy-duty granny gear with an overall length of 10.7" they are easy to adapt into a jeep, but finding a good one may be hard. they were only used by GM from 48-68. all the info you need here....
http://www.novak-adapt.com/knowledge/sm420.htm
 
The sm420 is a great tranny but i dont understand why its being suggested. It is a gm transmission and needs an expensive adapter for the dana 300. New to building i would think stock parts (guarenteed to fit) would be smarter. A t18 has a 6.32 first gear and can mate to a dana 20 with no high dollar parts. You can even find stock drive shafts to use instead of having to have them built. As far as road driving all trannies a have a high gear of 1 to 1 unless its an overdrive. So it doesnt really affect high way driving. Your choices to get a higher top end include rearend gearing, tire size, and going to an overdrive.
 
so do i have a t150 in mine? its stock from a 78 cj 5 3 speed. i'm not really sure what any of the drive train is i just know that i have a dana 30 and an amc 20. but i'm looking to upgrade to a d44 or d60 in front and prob a 14b in the rear with prob 4.88 gears but gearing isnt final yet just what i'm thinking as of right now
 
78 should be a T150/D20. I agree with sawdoff, T18/D20 is the easiest, probably cheapest. Be sure its a 76-79 CJ T18, Ford and J-truck T18 require a littel more work
 
is a t 18 a 4 speed or a 3 speed? i'd like a 4 speed just bc the fact i'm gonna be running it on the road i'd like the extra gear
 
Baker said:
is a t 18 a 4 speed or a 3 speed? i'd like a 4 speed just bc the fact i'm gonna be running it on the road i'd like the extra gear
Click to expand...

its a 4spd, but still really only 3 usable gears on road. First gear is granny low, unless your tires are way over sized for your axle gears, you'd start out in second gear most of the time. Both the T18 and T150 have top gear of 1:1 (no overdrive)
 
still it'd have decent road speeds without tackin out wouldn't it? i'm really just looking to get about 75 out of it so i can travel highway speeds and the granny gear is what i want to crawl with so i'm thinkin that might be the way to go
 
All of the 3 speeds and granny gear 4 speeds have a top gear ratio of 1:1. Top speed and rpm range all depends on tire size and axle ratio. There isn't a good 5 speed option for a cj5, unless you plan on stretching the wheelbase.

The t18/dana20 may be cheaper than the sm420/dana300, especially if you already have a useable dana 20, but the strength you would gain may be worth the extra expense. Especially if big tires, low gears, and that 360 v8 are in play. But that's just my opinion. Another downside to the sm420 is parts availability, they are getting harder to find.
 
You could bolt in a CJ T18/D20 combo with no fab work and be driving the same day for under $500. It would work fine with the axles you have now and all you would have to do when you go to HD axles is upgrade the D20 rear output to a HD one. Its cheap, quick, and gets you wheeling the soonest.

Bob
 
thank y'all for the input i'm thinking im gonna end up looking for a t-18 i want something thats got good crawling gear and still be able to run down the road, which looks like the t-18 should do the trick if i have my axles geared right? any suggestions on what to gear them too? i'm gonna end up putting a d44 and 14b in it found a set i'm buying shortly.
 
That T18/ Dana 20 combo will take almost anything you want to throw at it. If you get to where you need a lower crawl ratio, you can always buy an adapter and put a dana 300 T case with it and if you want lower ratio than that spend money and put the 4:1 low kit in the dana 300. :beer:

Are you planning on 4 link and sliding the axles out? If so, you have more room to work with as far as drive line length.
 
yeah i'm planning on 4 link and cutting the rear wheel well straight back and cutting the back at an angle like you see on alot of jeeps to get more clearance and i wanna slide the rear axle back not sure what i'm gonna get for a wheelbase but i know i wont be happy with the stock cj 5 wheelbase
 
The only issue I can see with the T18 and D20 combo would be crawl ratio, depending on tire size. If youre sliding your rear axle back, that means you should have room for a doubler. In the event you need it, you can always do that later.
 
I'm thinking I'd like to run 38's. I have the means to build this jeep how I want it and do it right the first time so that's what I'm doing. Wife's talking about trying to have kids within the next 2 years so now is my time to get it done so I don't have to sell it. So would a t 18 hold up to 38s and a 360? Also what's sye mean I see alot of people talkin about it just dont know what it stands for?
 
yeah the T18 will be fine with that, the weak point is the D20 rear output. There is an upgrade to the D20 available somewhere, I figired I'd look into it if I ever broke mine, never had to.

The SYE is a "new" Jeep thing, Slip-Yoke Eliminator, you dont need to worry about it. The Wrangler and XJ Cherokee have a fixed rear driveshaft, the yoke of the d'shaft slips in/out of the t-case rear output as the rear axle articulates.
 
Anybody know where I can find a t18? Lol
 
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