AW4 vs. AX15

OK here goes, my 2nd total noob question. When I get my XJ it will not be my DD. I want to use it to go exploring, camping, do some local trails as well as head into Nevada or Arizona. I also have a 17' bassboat that I will tow once in awhile( I live on a private lake so most of the time I only have to go 2 miles to launch), but there will be times I would like to venture out with the boat. I need it to be highway friendly and I don't have,at this time, any plans to conquer the gnarliest 4x trails that God has created. I'll prolly end up with 32's or 33's on a 4 1/2" lift, with some trimming, rear axle swap,(I'm thinkin Ford 8.8 with discs for stopping power when towing). I've done a few searches but they came up empty so here is the question:

AW4 vs AX15 Is there any advantage of one over the other. I would rather drive an automatic for obvious reasons, but would I be giving up performance?

AX15 > * (except NV3550)

The AW4 is a good auto box, but runs warm, if you are going to tow with it keep it in 3rd or lower and install an auxiliary cooler. It does chop a couple miles per gallon off your fuel economy, and isn't as fun to drive.

You do get deeper effective gearing with an AX15 than an AW4, you can compensate for those 32s by installing 2 or 300 dollars worth of junkyard axles that you can find anywhere in the country instead of paying ~280 per axle in gears plus another hundred or two per axle for install as you would have to with an auto. In fact, looking at a gear ratio calculator, an AX15 and 33s with cheap 3.55:1 junkyard axles is actually going to be torquier off the line than an AW4, 3.55:1 stock gears, and stock tires. I think they overgeared the standards to make them easier to shift and preserve clutch life, but I honestly couldn't tell you for sure.

Autos are way easier to find. Aside from all this, it's really a matter of personal taste. Honestly, I have 3 AW4 equipped jeeps right now, and one 5-speed truck. The 5 speed is way more fun to drive than any of the jeeps, and I've bought all the parts to convert one of the jeeps and am looking for the parts to convert another.

It's really a personal preference. I have an AX15 and love it but there are times i wish for the convenience of an auto. The manual requires less regular maintenance and has no electronics to go out of whack. But you have to deal with clutches and slave cylinders and such. The manual doesn't lose as much torque as an auto either. I would say its a wash. For me anyway I like the basic reliability of the AX15, its not about the fun. Fun is quick shifting a short throw on a Mustang, can't really drive an XJ the same. Like Kastein said autos are more prevelant and if you take care of your AW4 it will take care of you.

i love my aw4. theres times i wish i had a manual, but you really cant beat the aw4s reliability. ive beat the crap out of mine, ran it dry once (broke a cooler line in the snow) and it still works like a charm at 250k, which is not unheard of. as said though, they run a little warm, so if you plan a towing, an auxillary cooler is a must.

Kastein, your replies are so full of info that my noob brain is smoking by the time I'm done reading them. I'm tryin to be a good student, based on somethin I read, I thought my gearing would be in the mid 4's with 33's. Especially if I wanted a little extra low end grunt.

What would my top speed be in 3rd gear with an AW4(I think thats what you recomended) is the AW4 a 4speed.

The AW4 is included in damn near every XJ with an auto... certainly every 4.0L equipped XJ you'd want to look at. It's a 3 speed with an overdrive gear.

Top speed isn't something you really should need to worry about. With 3.55s and 33s (horrible gearing, should be more like 4.10 or 4.56) I can hit 90 in second gear, even towing a 2000lb trailer. You can tow at any road legal speed no problem with a trailer even limited to 3rd, by the time the trailer weight starts limiting you, you shouldn't be going that fast anyways because the brakes won't be sufficient.

I tend to write too much rather than too little... I learned most of what I know from this site, along with working on my jeeps and my friend's jeeps, so I figure I should pass the favor on :thumbup:

mongolchuck said:

For me anyway I like the basic reliability of the AX15, its not about the fun.

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I respectfully disagree entirely.

Dest said:

I respectfully disagree entirely.

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Hey Dest, could you elaborate on this, so far the jury is split. So hearing some reasons could help us noobs.

I just hate starting from a dead stop on an uphill incline with a stick. Same thing applies pulling a boat up a launch ramp. once the clutch is all the way out its no prob, but getting your forward momentum started sometimes isnt alot of fun. Guess its not bad if everything is working properly. Plus I've been doin it with a 2.2L S10 truck, lol, not a whole lot of power.

I have always been a manual trans guy, and have the AX15 in my XJ.

However, as slush boxes go, the AW4 is a damn fine transmission.

I have considered switching over to the AW4 lately (getting old, bad back, sciatic nerve issues), but apparently my Son has a FI 4.3 lined up in my future which means a different auto for me.

Keep in mind that a manual trans equipped XJ will come with 3.07 gearing while an AW4 equipped XJ will come with 3.55 gearing.

For a DD Id take a 5 speed any day. The first Jeep I wheeled was my dads '00 TJ SE with a 5spd. TONS of fun on and off road. With the bigger tires and the 4 banger, and Auto would really suck.

But on my trail XJ I love my AW4. Its really an awesome trans behind the I6. Its perfect for places like Rausch Creek. That said, when I build my JeepSpeed XJ (one day......), I plan to install an AX-15.

As far as durability, AW4 > AX15.

Also, Ken you're not taking into account the torque from the converter when you say that an AX15 will be torquier off the line.

Believe me, I love stickshifts (have an NP435 going into my MJ) but I've seen far too many AX15s kick the bucket, but have rarely seen an AW4 croak in the same situation.

I had 300k miles on my AW4, about 200k of those were without a trans cooler, and about 40k of those miles were on 33s and 35s. It still shifted great when I sold it to someone.

Yeah, I forgot the converter :dunce:

I definitely agree on AW4 reliability, I have done things to my current one that I almost expected to break it, I just didn't give a damn because I was pissed off and stuck. It still works great, the TCU took a dump on me but I'm pretty sure it's a loose connection from being in a jeep getting bounced off rocks and stumps.

Join the AX15 For Life club! I'm on my 3rd XJ with an ax15(had a ba10 on my 88 and now have it on the 88 MJ) and never once had an issue with one(these clutches last long too). I don't recall reading people blowing them up(not saying it doesn't happen). You can't go wrong with the aw4 either, so it comes down to preference: do you like shifting or not? There's always 3.55s from aw4 xjs in the JY so that'll make the ax15s better geared so the 3.07s shouldn't be the issue.

AX15 vs AW4... it really is about personnal preference. Both are fine transmissions and each one has it's ups and downs....
With AW4's you have to worry about overheating it
With AX15 you have to worry about the clutch (don't slip it )

Otherwise then that... do what you prefer to deal with as you can get kits for your AW4 to make it behave like a stick shift if you need it

With that being said all my XJ's were stick shifts... well correction... one was an automatic... for about two weeks... then it was a stick shift again

I don't think an AW4 would have survived what my AX-15 has.

As far as not slipping the clutch, I've slipped mine plenty, with an unknown amount of miles on it, it still works.

thankfully I've gone from 3.73's to 4.56's, so no more of that bull.

I think it's preference, both are plenty stout behind a stock 4.0. The AW4 needs heat prevention, the AX-15 is terribly picky about what fluids you stick in it and shifts like a dump truck, 2nd gear in freezing weather is not going to happen until it warms up. Your choice.

Thanks for the input guys. I'm still confused..LOL I guess thats what sucks about beeing a pre-noob. I have no eperience with either. Guess I'll just see whats available when its time to buy.

Thanks again

Think about this. You're 4 wheeling in a tough spot. You've got 2 feet. How many pedals do you wanna deal with only having 2 feet? 2 or 3?

My first XJ had an aw4...I got really bored with it and bought a new wrangler. Got bored with that and bought a 99 XJ ax15 and love it. It's all preference. Hard to beat the aw4's reliability...but the ax-15 still is a good tranny.

I'd say buy the best condition XJ around you at the best deal and decide which you really want to drive more. Sometimes I miss the convenience of an automatic, ie traffic and other times I wish my wife or someone could drive my XJ (and then remember they don't/won't drive stick), but overall I still love it.

The AX15 in my 92 never had a single problem over almost 500,000 miles, even with far to infrequent fluid changes.

I have an AW4 in my 96 now and even though it's an outstanding tranny for this vehicle and rugged as hell I still wish it was an AX15.

I also agree about it being way more fun to drive plus being better on the highway. I did a fair bit of towing and had no issues and better mileage.

Regarding how many feet to worry about - if you're a full time 5-speed driver, it's more first nature than second.

(JrTxJ: sorry to hear that about the wife.)