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Unimog axles in a tj

12K views 37 replies 17 participants last post by  bsharp704 
#1 ·
i have an 01 tj with an 8" long arm and coil over shocks. i am running 37 inch iroks on 17 inch wheels. my axles are still a dana 30 front and dana 35 rear. they have both been regeared to 4.88 and the rear has chromoly shafts and a detroit locker. i realize that my axles are way undersized for what i am running so lets just skip all that and get right to it. i NEED bigger axles but don't know what to go to. i know that i REALLY want to run portals. i would love to have pro rock 60's with AIM portals but thats over $22,000. I have recently been pointed in the direction of unimog 404's or possibly unimog 406's. these axles are portals as well and the cost is almost 1/3 of the dynatrac pro rock 60's. does anyone have much experience or knowledge of these? i'm trying to save money up now and would like to take this next step with my rig within a year. any info, suggestions, and help would be greatly appreciated.

:confused::confused:
 
#4 ·
I have a little experience with them, as I own a 404.

I cant remember exactly, but I seem to recall a combined ratio between the hub and the diff to be about 7.56:1.

They're set up to run as a torque tube, so you'll need to convert the pinions to run drive shafts. I don't know what all is involved in this process. I do need to replace a wheel cylinder on it, and i'm not really looking forward to it at the moment. Stock 404 suspension is coil, so that may lead to be beneficial.

Stock brakes - i don't believe anything smaller than a 20" rim will clear the brake/hub assembly. The drums are freaking huge. They also have a massive 6 bolt pattern, and stock rims are fairly narrow. Mine's running a 10.5 R20 that fit well. Clearance to the pumpkin is ~17.5" with tires at normal pressure. Another buddy has 39" iroks that are 12 or 14" wide and not quite screaming for a wider rim, but for what he wants to do they're working ok.

If you run highway trips with it, some guys choose to monitor the hub temps pretty closely.

Another option are the SEE axles, as they tubes are bolt-on replaceable, but they're a bit more, but considerably stronger.
 
#6 ·
i've looked at places like the mog shop who can do all the pinion and disc brake conversions and then ship the axles to me. all conversions done and shipped was around $7,000. not cheap but still way cheaper than dynatrac pro rock 60's with aim portals. from what i've learned, they will also set them up with a more convenient bolt pattern and the disc brake conversion allows for a smaller wheel option.

i'd never heard of the 419's until i followed the previous link to the buggy build in which that is what he was using. i like the gear ratio in the 419 a little better. and 4 wheel steer is definitely a bonus. i plan to run at least a 44" tire with these axles so the 6.54 ratio doesn't sound that far off either but i'm not sure i need something as heavy duty as the 419's. which would be better for my type of wheeling, 404's, 419's, or other i do a lot of wheeling on drummond island and i just got back from a 2 week trip out west where i ran the rubicon, deer valley, and 5 days in moab so i am progressively starting to run tougher terrain. this is the reason i'm really looking at bigger axles i'm not going to be able to do the fab work myself, unfortunately, to put these axles in so i'm gonna have to rely on someone, or a shop, to work on it for me. i've turned every single bolt on this jeep myself as well as worked on lots of other jeeps for guys but i'm just not setup for heavy fabrication work and i want to the end result to be right.

where can you get these axles and how much? do you know any shops that have experience with installing these? i think while i am installing the new axles a will also look at moving the front and rear axles outward and going with full hydraulic steer. i'm afraid to even think what this may cost in the end. maybe it's just a big dream. Lol.
 
#7 ·
How much HP do you think you will end up with? In other words unless you are planning on running 42" and larger tires with 400+ hp i think anything over 1 tons is over kill.

In my opinion a Pro Rock 60 is a waste of money and people who buy those dont really know what they need. You know that axle because they spend lots of money in advertising and sponsoring.

If you are dead set on portals the mogs are great. Also another option would be to put the Aim's on a Corp 14 both front and rear.
 
#8 · (Edited)
i'm still running the 4.0 right now with future hopes of running a 4bt cummins diesel and 44" tires or larger. either way i'm not looking at alot of horsepower. a built 4bt might push 300hp and 500lbs of torque if lucky. i'm pretty set on portals though for the clearance aspects, and i want something that i can thrash pretty hard on the rocks and not have to worry about ever breaking.

i saw an article last month in peterson's where terra traction in florida built a tj up. it was a tj body and interior on a tube chassis with 404's and a 4.0. it looked like a pretty awesome machine. i started to view myself going in that direction. i thought about just starting with an ARR chassis and building off of that but then decided that i wanted to retain my jeep body and interior for the creature comforts and the ability to keep my top on in bad weather.

i hadn't thought about the corp 14's with aim portals though. got any info on them? how wide of a set up would that be flange to flange? any ideas on availability and price?
 
#9 ·
mike the guy building the buggy in the link bought like 10 sets of those axles.he still has some for sale i believe. pm him.he has done a bunch of research and is a good guy to talk to about this stuff.
 
#14 ·
My opinion is the 419 is the way to go, they have the U1300 portal boxes which are slightly stronger then the 406 boxes (much stronger than the 404), the 416/419 use large stright cut gears so you can run them either way (the 404 do not use straight cut. The 404 are nice, but i hear the portal boxes can break when abused in rocks. I like the 419 because they have factory disc breaks (the disc are larger than my toyotas flywheel), the axles roughly weigh 650lbs (pretty light for this kind of strength IMO), stock 55* turning radius, 1 3/4" double-cardam axles shafts, air lockers, 6:52 to 1 overall gear ratio, and awesome ground clearance - may 6" more than normal. I recentered my rims to widened my width with 49" tires to 89". I really don't know how well they will work as i have only driven my buggy off the trailer for the first time this morning at the exhaust shop.


I do have a pair of steer axles i may want to sell, although they need pinion gears....
 
#25 ·
Yea the 303 is less strength then the Dana 60. But the weight savings over the 404/406 is a few hundred pounds. And the cost is a lot less to make it into a nice off road axle. Also the width is comparable to what you have in the tj now. Look on pirate there are a few people building them with parts beefed.

I'm not into portal axles due to the low speed requirements making it a 45mph and under axle making it a short range/low speed axle. But for ground clearance for the cost of around a Dana 60 it is a good option.

The fact that he is looking at putting that heavy frito lay engine in there may be another reason to go with the 406 though.

http://lucienfrelin.com/jeepbuild/tag/frito-lay/

There are lighter/better diesel options out there if you want to go the diesel route. Don't get me wrong it is a cool engine(i'm just not a diesel nut knowing how picky they can be) I'm just saying there are lighter options.

http://youtu.be/Rugr6XdFJwQ
 
#26 ·
thanks for all the links and help from everyone so far, i am learning a lot.

i've been looking at the 303's and reading several articles on them. i didn't realize that portals had such a low speed rating. i don't do very much road running, just they occasional from the house or hotel to a trail head. is there any portals that can be run at 65 mph for lets say, an hour, if need be? if i put portals under my jeep am i eliminating all hopes of driving it down the road like normal? maybe i have to run a more traditional axles and forget abouth the extra ground clearanc that a portal provides.

as for diesel powerplants, what other options are favorable for jeeps. i referred to the 4bt because i had read other articles where it was used and people had lots of good things to say about it. i started looking around and i found two of them at a local heavy truck shop that were readily available.
 
#32 ·
Are you building a Jeep to wheel or a Jeep to DD? If you are building a Jeep to wheel why be concerned with how it drives on the road? If you are building a Jeep to DD why go nutty with custom everything?

At one point, until a wise little grasshopper talked some sense into me, I wanted a Jeep that was very capable on the trail, but still streetable. Why? Why should I give up off road ability just so I can drive it to DQ once a month?

It really comes down to off road toys are for off road and on road vehicles are for daily driving. Be honest with yourself and don't handicap the vehicle with pipe dreams.

Also, once again per the wise little grasshopper, with portals you need to think about packaging and the extra challenges that brings with everything sitting 6" above the axle. Either you get creative with the torch on your tub or you end up with something retardedly tall like that MBRP JK they are building.

I used to love the idea of portals, but I have since realized that its not worth it. And considering how few full body rigs out there you see with them I think that's probably the common consensus...but good luck anyway.

Just my $.02...
 
#27 ·
IMHO, if you're worried about running 65 mph and portals, maybe they're not for you? Lot of capable rigs out there without them.

As for what other diesel fits - a 6.2/6.5 GM diesel is relatively light weight and not too different than a SBC install. Before choosing a diesel, I ask you to consider a few things:
1. Do you like smelling like diesel exhaust?
2. Does your co-pilot like the smell of diesel exhaust?
3. Have you breathed diesel exhaust for hours on end?
4. Wheel with others often?

I'm not, contrary to popular belief) trying to be an asshole; I was dead-set on installing a 6.5L GM diesel in my old XJ. My reasoning was that is weighed about the same as the 4.0L, I'd get better fuel economy as a DD, and it would be pretty cool to have a low-rpm torque monster.

Then - I had the chance to wheel in a group that had one CUCV 6.2L Blazer. Awesome truck, set up nice, but every time I was behind him waiting for an obstacle, I'd get bathed in his exhaust and start feeling sick. I took several breaks just to get away from the smell and sick feeling.

Not saying everyone is that way, but after the not-so-warm reception from other people from my old PSD tow rig's exhaust, I dropped the idea of a diesel in a wheeling rig.

YMMV.
 
#28 ·
Its funny, everyone likes the idea of a torquey engine, but, in just about any properly gear Jeep, torque isn't a problem. My Jeep with 258, 37s, and just a 3 speed auto and 4.10s, torque was never ever an issue. Heck, my Toyota with 38.5s and a 4 cyl crawled up everything, it was just an issue of no horsepower.

Its horsepower that just about everyone needs. Spin the wheels to get wheelspeed and heat the tread, get through deep snow, climb hills, sand dunes, mud, etc.

4BTs are what, 130hp and about 750 lbs. So adding 200lbs to the nose, and you'll have to dowork just to get get up to a stock 4.0 horsepower level, which is already underpowered for a Jeep.
 
#31 ·
The volvo303 has a Max speed of 65mph. Which is faster then a mog but you still need to consider the heat generated at those speeds. The "cruising" speed for like a hour would be around 50 mph.
If you were to drive for that long day after day plan on constantly changing the fluid in the portals and checking the seals. In some cases they use different fluids in the portals then in the axles.
The fluid in the axles seal can rupture at higher temperatures putting additional fluid into the portal.
You would have no way of telling this if you did not constantly check the portal level.

The portal left unchecked then overfills and that seal ruptures. The fluid goes out the portal seal and then it begins to run dry. The portal gears will chew them self's up quickly at 50 mph.

The aftermarket has a fix with better seals. But that is a example of what can happen at higher speeds.

Portals are good for clearance and the 303 is rather simplistic in design compared to a 404. They can be beefed to be a very impressive off road axle. But have no real place on dry pavement.

As far as the diesel. Consider the geling that happens in the winter, The additional cost of everything, the weight, and the fact that you really need a turbo or it is a dog which means more parts and cost.
 
#37 ·
LMAO!!! that's exactly what my wife said. well long story short, the initial buy of the fabtech 8" krawler lift with coilover shocks and 5-37x14x17 irok's with wheels was just a fuzz under 10k. not cheap by any means. i know the price on some of this has come down since i bought it but, that's what it was then. the rest is just a blur but poison spider bumpers, rockers, drop down tire carrier and other various armor, plus powder coating aint cheap, and warn doesn't give power plant winches away either. borla stainless steel header and exhaust system, sent trans out to be built up, teraflex sway bar setups, lockers, gears and carriers, axle shafts, etc, etc, etc....

i'm sure you've had builds before that if you were to go back and add up everything you've put into them it would suprise you. it's not always the big purchases that cost the most, it's the constant little things that you keep adding that break the bank.
 
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