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what diff's and gears?

mitsumotors

NAXJA Forum User
Location
Winnipeg
i have an '88 xj and i'm puting a rc 3" lift with 31 inch bfgodrich A/T's. its only got a crappy 231 transfer case with the disco front diff, the dana 35 rear and not too sure what diff i got up front. no lsd. and the also shitty puegot BA-10/5 tranny. what would you guys do with this setup to make it runn better for lifting and bigger tires. some people have said to change the gearing, some have said to put a locker, some said not to touch the dana 35 cause its garbage to start with, and some have said to switch out the transfer case. what should i all do here? i need some options, and it would also be nice to know why. thanks guys.
 
The Dana 30 can be made into a non disco.

Swap out the Turdy 5 for a 8 and 1/4 or a 44

Put in 4.10s

Lockers

Whats wrong with the 231...?
 
You don't HAVE to do anything to run the lift. A re-gear will be good to get your rpm range back to ideal and make it more driveable. Lockers are great for traction upgrades.

On 31's you won't have problems with locking the d35 unless you're stupid with the skinny pedal.

What makes you think the 231 is crappy? It is basically the most common T-case in Cherokees and there is nothing wrong with them. I don't know where you're getting all of your information.
 
i just don't like the 231 because everyone keeps telling me that i can't use the 4hi for long periods of time. i want it to be more versitile so that my fiance can just hop into it in the winter on a snowy day and just pop it in 4hi and go, regardless of weather its ice, snowy roads or just a few patches of ice on an otherwise clear highway.
 
one thing i like about the dana 30 is that it disconnects when in 2wd which is good for the gas mileage. why do people not like the disconnect diff?
 
also, someone told me to just take a rear diff out of 4cylinder jeep. whats with that? what kind of diff is in a 4 cylinder? whats so good about it?
 
mitsumotors said:
also, someone told me to just take a rear diff out of 4cylinder jeep. whats with that? what kind of diff is in a 4 cylinder? whats so good about it?
FAQs and searching are beautiful things.





..the four banger has 4.10s in it. and you will have to regear the front if you swap that in. and just because its a 4 banger doesnt me it doenst have a 35 bud so its not as simple as that.
 
its the same diff, but they are often geared to 4.10 which means you'd have to regear the front to match.

I've driven my Jeep for an easy week plus on end in the snow in 4hi without troubles, I'm not sure where your information comes from but I'd reconsider your sources.
 
mitsumotors said:
i have an '88 xj and i'm puting a rc 3" lift with 31 inch bfgodrich A/T's. its only got a crappy 231 transfer case :bs: with the disco front diff, the dana 35 rear and not too sure what diff i got up front. no lsd. and the also shitty puegot BA-10/5 tranny.:yelclap: what would you guys do with this setup to make it runn better for lifting and bigger tires. some people have said to change the gearing, some have said to put a locker, some said not to touch the dana 35 cause its garbage to start with, and some have said to switch out the transfer case. what should i all do here? i need some options, and it would also be nice to know why. thanks guys.

Damn that is a lot of shit and crap!! You should be more carefull with the advice you get. Yes, the tranny you have is not the best.....:puke: but the 231 is a very good transfercase! Your 30 can become a non-disco with new axles and a cover plate. The 4 cylinder has lower gears already in it, I believe 411. Use the search feature here and you will be rewarded with a wealth of info!! And finally...WELCOME!!NAXJA
 
the 231 will actually hold up to a very mild V8 believe it or not. so there's no problem there. it is the most commong and also widely prefered transfer case among jeeps.
as for the 4hi. you don't want to drive it on dry pavement. BUT there is no time limit on how long to drive it. i've had my 4hi engaged for over a week if there was snow/ice out. and besides....you can shift on the fly. so just teach your g/f that if it's slippery out, to pull the lever into 4hi as long as she's doing less than 55mph. and when the roads clear up like in a well plowed city, then just push the lever back into 2wd. no offense, but even the biggest blond "should" be able to understand that after such a simple explanation.

the reason people are telling you to pull the rear axle out of a 4banger is not because the axle itself is an upgrade, but because it "usually" has 4.10 gears in it. which means that it would save you a good amount of money in parts purchase and labor because now you only have to buy gears/install kit for the front and pay to have it installed. essentially cutting your re-gear cost "almost" in 1/2.

You have a Dana30 front axle. you'd have to look to see if it's vacuum disconnect or not. if the passenger side of the axle has a round cast "sleeve" looking section on it with a big "pump" looking thingy sticking off the backside of it, then it's a disconnect axle. there's really nothing wrong with that, but if you want to eliminate it, it can be done relatively easy. on a easy/medium/hard scale, i would rate it medium-hard for a beginner, and easy for somebody with more mechanical experience.
and the front disconnect axle really doesn't giving you that much extra gas mileage to justify keeping it if that is the only reason for keeping it. after all, that's part of the reason why they eliminated it from the factory. there really wasn't that much savings in the gas department.

hope that helps some.
 
mitsumotors said:
if i had the 4.10 gears out of a four cylinder, about how hard is it to install on a dana 35? or how much does it cost to get it done?
you are not going to take the gears out you are going to swap the entire axle. it'll probably cost you $300-$400+ an axle to put gears in. Thats why you swap the entire thing. $100 an axle for axles out of a 4banger so $200 for the entire rig for gears
 
HOLY SHIT......Worry about the lift first. SEE once you start working on your jeep you get this click. kind like a meth head. You start obsessing over the brick shaped suv, and you cant get enough of it. By the time you need to do this swap.... You already have done it in your head 10 times. As far as questions. This is the place. But no the swap isnt the hardest thing to do.
 
the front is pretty easy because you can disconnect everything without loosing any fluid or anything. but with the age of your vehicle, some of the bolts might be pretty rusted. so i hope you have a good air compressor and air tools, and a few friends that can be bought for some beer.

the rear is either easier or harder depending on how you look at it.
you can either disconnect the brake lines, swap the axle and then you'll have to bleed the brakes, or you can actually leave the brake lines connected, and unbolt the backing plates instead. then you use bungee cords to hold the backing plates and the entire brake lines up and out of the way while you swap the axle, and then just bolt the backing plates back on. then you don't even have to open the brake lines and don't have to bleed them.

again rust will be your enemy. start making friends with PB Blaster (available at most parts stores), and start using it days before you even attempt to start the project, so it has time to soak in.
 
As mentioned, you can swap the two piece axles out for one piece units from a 95+ XJ or any TJ D30.
http://www.stu-offroad.com/axle/yjd30convert/yjconvert-1.htm

You can swap the BA5/10 for a AX15 for a better trans.
http://www.4wheeloffroad.com/techar...x15_bolt_on_transmission_swap_jeep/index.html
http://jeep.off-road.com/jeep/article/articleDetail.jsp?id=261459

For the Full time 4wd option, you can swap in a NP242.
http://www.weatherlover1.com/jeep/242.htm

Make sure you get a transfer case that has the same spline count as the 23 spline AX15.
 
i have basically the same xj as you, dana35/dana30 with axle disconnect, ba10 and 231 transfercase. i have 4.5 infront and 4" in the back with 31's. the lift consists of 3" coils with 1.5 spacers, adjustable track bar, upper and lower adjustable control arms, zj tierod in the front. the back are 3" leaf springs with jks 1" lift shackle.

i regeared to 4.10 because i didnt want to swap axles but in the long run, if you can find axles from a 2.5 it would be cheaper. i dont have any vibs, older xjs with 5sp are less prone to vibs because the rear driveshaft is a bit longer and less angle. as for the tranny, it is working just fine after 225k miles. as for the axle disconnect, it also works fine and have had no problems. iam debating about putting in a lunch box locker in the dana 35 because oof the strength issue.
 
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