Considering new gears and locker options

[txag88]

I'm in a 78 CJ5 with all stock axles and gears (3.54 ratio) on 31"x10.50"R15 MT tires. I'm in the decision/budgeting phase for upgrading. I usually only highway drive it once and a while to keep miles on it (DD is a 4x4 half ton, so snow/ice/heavy rain aren't really a concern for the Jeep). I know I need to upgrade to one piece axles rear. But while I'm at it I'd like to put lockers and possibly lower my ratio. Thinking about LOKKA (previously Aussie) front and rear and 4.10 gears. I know that mechanical, ECTED, or air are the best options, but I'm trying to keep this Jeep to a budget toy, not a pro-grade crawler. I humbly open the floor to any suggestions, arguments, etc.

 

[Jimbos76cj]

What size tire are you going to? Transmission ? maunual or auto?

Honestly when it comes time to upgrade my axles I always look for some one who upgraded thier and are looking to sell. I would try to find a set of wide tracks whiles I was at it. you should be able to buy a set of stock CJ wide tracks for around $250.. Im sure its more then you budgetted but you will be alot happier with the wider stance. For a AMC20 rear I would definately upgrade to one peice shafts. As for the choice of lockers... auto lockers normally take a while to learn how to drive with on the road and seem to be love em or hate em.

 

[txag88]

I actually just came down from 33" to 31", and I really like my new size. PO put on the 33", but from what I can tell, it's a stock suspension, so I was getting little to no articulation with the 33". T-18 and Dana 20 Transmission and Transfer Case .

Would you recommend spacers vice wide-track?

 

[IOPort51]

Axles are expencive!! that said, I am guessing you have a T-150 3 speed with a Dana 20 TC. 3.54 R&Ps are not the worst thing that you could have and drop in lockers are pretty easy installs, if your careful not to change any shims. You will have to pull both carriers. the lockers only fit open carriers so if by some miracle you have Limited slip it becomes a problem.

changing ratios may require new carriers and professional help to put the axles together. you can real easy put a couple of grand into an axle and still not get every thing you would hope for. like I said, Axles are expensive.

I'm in a 78 CJ5 with all stock axles and gears (3.54 ratio) on 31"x10.50"R15 MT tires. I'm in the decision/budgeting phase for upgrading. I usually only highway drive it once and a while to keep miles on it (DD is a 4x4 half ton, so snow/ice/heavy rain aren't really a concern for the Jeep). I know I need to upgrade to one piece axles rear. But while I'm at it I'd like to put lockers and possibly lower my ratio. Thinking about LOKKA (previously Aussie) front and rear and 4.10 gears. I know that mechanical, ECTED, or air are the best options, but I'm trying to keep this Jeep to a budget toy, not a pro-grade crawler. I humbly open the floor to any suggestions, arguments, etc.

 

[IOPort51]

Axles are expencive!! that said, I am guessing you have a T-150 3 speed with a Dana 20 TC. 3.54 R&Ps are not the worst thing that you could have and drop in lockers are pretty easy installs, if your careful not to change any shims. You will have to pull both carriers. the lockers only fit open carriers so if by some miracle you have Limited slip it becomes a problem.

changing ratios may require new carriers and professional help to put the axles together. you can real easy put a couple of grand into an axle and still not get every thing you would hope for. like I said, Axles are expensive.

A T-18 close or wide ratio?? whichever it is I would not sweat changing ratios with the T-18 for the kind of wheeling you describe.

 

[txag88]

A T-18 close or wide ratio?? whichever it is I would not sweat changing ratios with the T-18 for the kind of wheeling you describe.

Wide, granny low.

And I do have open differentials on both. I've been told that a lunchbox isn't a good idea front because it's awful to turn on pavement, but theoretically, I'd rarely if ever have my front hubs locked in on pavement.

 

[Petescj]

Wide, granny low.

And I do have open differentials on both. I've been told that a lunchbox isn't a good idea front because it's awful to turn on pavement, but theoretically, I'd rarely if ever have my front hubs locked in on pavement.

That is correct. And they suck in the snow but you covered that already. Ive heard good things about the Detroit true trac for a front axle but have no expierence with it. You may want to just hang on to your spider gears and go lunchbox lockers in both. Then if things change ( they do that sometimes ) and cash is low you can atleast go back to the open diff in the front.

 

[txag88]

Pete, 3 piggy back questions, then:
(1) Any advice on changing ratio? IO recommends keeping 3.54.
(2) If I were to install lockers one axle at a time, which would be more beneficial to do first?
(3) Is it normal/kosher to mix and match LSD and lunchbox?

 

[Petescj]

1. Im not gonna go against IO on the gear ratio "unless you feel your going to go up in tire size at some point." 3.54s are fine for 31s. If you think may move up in tire size soon Id start saving money for regearing.

2. My opinion on this can be controversial. I would say the front. I like to have both fronts locked to help crawl over obstacles. If crawling isnt your game then you would probably benifit more from the rear first. If you decide to go with the LSD front then I definately take the rear first.

3. Yup its a decent combo , but its usually used for daily driver vehicles. The intent of the LSD up front is to help alleviate the steering issues you get with the Lunchbox lockers.

 

[Old Dog]

I'm kinda with IO here. with 31" tires and the T-18 your current gears seem ok. but only you know for sure.
If you really feel the need for taller gears than 4:10s would be fine but you will need a new carrier in the front, the 20 will be ok.
Mixing lockers and LS is fine.
I had a Eaton Truetrak in the front of mine, I worked great as long as you kept both tires on the ground.

 

[Petescj]

I'm kinda with IO here. with 31" tires and the T-18 your current gears seem ok. but only you know for sure.
If you really feel the need for taller gears than 4:10s would be fine but you will need a new carrier in the front, the 20 will be ok.
Mixing lockers and LS is fine.
I had a Eaton Truetrak in the front of mine, I worked great as long as you kept both tires on the ground.

Im always a lower gears kinda guy . The T-18 is the X factor here. That really helps you out. You said you didnt get good articulation so I assume you had it off road a bit. What did you "feel" , seat of the pants so to say? On a side note we never mentioned 1 piece axles. A locked AMC20 should have them if you get the tires bound up in your style of wheeling.

 

[txag88]

Im always a lower gears kinda guy . The T-18 is the X factor here. That really helps you out. You said you didnt get good articulation so I assume you had it off road a bit. What did you "feel" , seat of the pants so to say? On a side note we never mentioned 1 piece axles. A locked AMC20 should have them if you get the tires bound up in your style of wheeling.

Yes, I've had it off road in both the 33s and 31s. First time I did significant wheeling and not just tooling around was this past weekend. Hit some rock crawls, deep soft sand, hill climbs, and some muddy water crossings. Was really blown away with how well it did, but I was Limited to the much smaller, smoother rock crawls due to my open diffs.

I got pretty decent articulation with the new tires. I like the finesse-style of wheeling: slower and more methodical, where you can challenge your rig and find its limits safely without breaking too much So "seat of the pants", loved how the CJ did. She treated me very well, and every time I take her out I get more excited about what she can do :drool:

They say every time you go wheelin, you add something to your to-do list, and lockers just got put up at the top!

 

[Old Dog]

If you like rocks than the LS might not be a good thing, as they only work when both wheels are on the ground.
At the same time a full time locker will make it really hard to turn.
If I were you I'd save up for a selectable locker for the front.
For the rocks the 4:10's might be a better bet, even with the T-18 .
And yes when you wheel your rig the list never ends. I would put under body armor at the top of the list myself.

 

[BusaDave9]

It would be nice to have 4.1 gears but is it worth it? I agree with the others, it's really not worth the effort and time to regear your axles. You are close enough. That being said a lunch box locker would be nice.
The biggest advantage of the Lokka and other lunch box lockers is that you can do it without a lot of work and worrying about gear meshing. On the other hand if you do decide to regear your axles then I would NOT use any lunch box locker. The carrier becomes the weakness at that point. If you are going so far as to replace the gears then put in a Detroit or some other locker.

Here's more info on lockers: http://www.jeep-cj.com/forums/f105/lockers-limited-slip-differentials-12434/

 

[IOPort51]

there are two t-18s, one with 4 to 1 and one with 6 to 1. I am betting you have the 4 to 1 but could be wrong.

 

[Torxhead]

There is another option of adding lower Transfer Case gears.

 

[GatorBate]

Here's my $0.2 worth... I have selectable lockers in both front and rear and I tend to use the rear locker twice as much as the front one. Don't get me wrong, I use them both!!

I think 4:1 gears would be the way to go also. I'm not sure if they make 4:1s for the Dana 20 though. I like it because it still runs good on the highway, but in low range its unstoppable. well almost.

Good luck with the build

 

[txag88]

there are two t-18s, one with 4 to 1 and one with 6 to 1. I am betting you have the 4 to 1 but could be wrong.

I'm pretty sure it's the T-18a with 6.32:1 based on the info in Busa's CJ encyclopedia:

According to the guys at Novak Jeep released 12 different versions of the T-18 . Most variations were different gearing and input shaft lengths. The most desirable T-18 's had the granny low first. These were referred to as the T-18a. All the T-18 's in CJ's from 1977 to 1979 had this T-18a wide ratio gearing.

Read more: http://www.jeep-cj.com/forums/f105/manual-cj-transmissions-12112/#ixzz2eSOkSXhl

I think what looks like the best option for the near future is to put a lunchbox in the rear and enjoy the 3.54 gears on 31s bc y'all are right that the 3.54s are a good match for these small tires. Sometime a little down the road (after several paychecks of savings) putting a Detroit in the front. Then further down the road (when these 31s get worn or blown), lift for larger tires, gear it down, with an Ox in the rear and leave the Detroit in the front.

 

[Jimbos76cj]

One peice axles, keep the 3:54's if that's what you have, selectable locker rear and lunch box up front. This is one of those thing that are expensive to do once but are really expensive to do twice. If you road drive it pay for the selectable rear. I'd recommend ox and upgrade to the electric actuator if you can or upgrade it down the road.

If you decide to do you own install on the lunchbox lockers the front carrier should have the shims between the carrier and bearings so they won't fall out when/if you pull it. The 20 on the other hand uses shims between the bearings and case so if you pull it and loose track of the shims you are now having to reset the rear carrier.

 

[IOPort51]

If you do the OX, pay someone to do it.