Relative axle strengths/ Tech Thread

[Ktmracer419]

Due to spending too much time on the internets and learnins much. I am bored and have decided to make a thread on axles. More will be added as I gain more smarts on the subject. I know Im missing a bunch of axles, thats because those axles suck and feel they arent worth mentioning, or i don't know enough about them. This is to be used as a guide and depending on your wheeling style you can get away with different setups than listed.



REAR AXLES:

Dana 35: 31" tire max, you can get away with larger tires, but carry a bushel of spare shafts. GREAT AXLE....if you plan on staying on stock tires and drive like a grandma. Sure you can upgrade shafts, truss it, etc, but then you end up with something better suited as a lawn ornament. plenty of available gear ratio's. this is a c-clip axle.

Chrysler 8.25 (27 spline): 33" tire max. still a smart idea to carry spare shafts. Beef Housing, not much afermarket, limited to 4.56 gear ratio. this is a c-clip axle.

Chrysler 8.25 (29 spline): 35" tire max. Same as above 8.25, only slightly stronger shafts.

Dana44 (30 spline) 35" tire max. Plenty of aftermarket. Gear ratio go up to 5.89, although I wouldnt reccomend it as your pinion gear gets awfully small. Aftermarket shafts are plentiful and a worthy upgrade if you have problems with snappage.

Dana44 (33 and 35 spline) 36" tire max. While you gain shaft strength, your gears become the weak link. Still a decent upgrade however.

Ford 8.8 (31 spline) 35" tire max. Stout axle, as long as you take care of its many weak points. Stock carrier is weak, housing MUST be welded to the tubes or they are prone to spinning. gear ratios up to 5.13 available. With the super 8.8 kit I would say you would be good for 37's (carry spare shafts) The super 8.8 kit gets you a c-clip eliminator, locker and 31 spline alloy shafts. this is a c-clipped axle.

The following axles do not have posted tire size limits because I don't have enough experience with them to give an accurate figure.

Ford 9" (35 spline, 40 spline,46 spline) yes i know there are 28 and 31 spline 9"'s available. but why get such a beef axle and leave weak shafts? aside from that this axle is the aftermarket king, ANYTHING is available for it. Early 9"'s have weak housings and a truss would be a smart idea. VERY LOW PINION good for grinding your yoke and driveshaft in the rocks. This is also a third member axle meaning the carrier,gears and whatnot are taken from the housing in one piece. geared and locked third members are available from most everywhere that does gears, just bolt it in and your geared and locked. High pinion third members are available and a very good investment (if you can afford it) the only place that does a worthy high pinion 9" third member is www.truehi9.com gear ratios go DEEP (5.89 iirc)

Dana 60 (35,40 maybe 46 spline) LOTS OF AFTERMARKET. available in both full float and semifloat applications. lower spline counts are available, but again, why build a strong axle and leave a weak link? gears go deep. some rare 35 spline semifloat axles can be had and are found in early jeeps and fords (good luck finding one though) upgrading a semifloater to 35 spline only takes a new locker/spool, stock bearings and seals will work. I am not familiar with upgrading a full floater to 35 spline, but spindle boring is needed. Plenty of gear ratios available.

toyota 8"

14 bolt, dookin axle, boat anchor, shaving is a must, HEAVY

Sterling 10.25, dookin axle, limited aftermarket

FRONT AXLE TECH:

Dana30. good for 35" tires when properly built. smart idea to carry spare shafts. for 95 and earlier dana30's without abs you can swap in abs equipped shafts or 96 and newer shafts for larger u-joints. spicer 260's are the smaller one and spicer 297's are larger. another upgrade is the spicer 5-760x u joint which is the same size as the 297's but even stronger (something to do with how its made) Plenty of aftermarket available for this axle including 30 spline alloy shafts. If you upgrade to the 30 spline shafts beware that your ring and pinion become the weak link. Wheel bearings also come as one hub unit, and will wear quickly if wheeled in mud or with large tires with low backspacing wheels.
high pinion gears go as deep as 4.88.
low pinion gears go as deep as 5.89.

special note for low pinion dana30's. don't put money into them. a high pinion dana30 from an xj is a direct swap and you gain ring and pinion strength as well as a driveshaft that wont spin in the rocks.

Dana44. good for 37" tires when properly built. stock shafts offer no upgrade over dana30 shafts. gear ratios go plenty deep.
High pinion offers slightly more ring and pinion strength over low pinion and keeps the driveshaft out of the rocks.

Good donors for a low pinion 44 (in a modern drivers side drop yj/xj/zj/tj) are the 1980-92 jeep fullsize dana44's. all are 6 lug with the exception of the hd44 found in j-20's. Waggy's offer a near stock width (61ish" iirc) and the most direct swap. J-10 44's are slightly wider(63.5") but other than that are very similar to the waggy 44's. These use a common 1310 u-joint yoke and with the right brackets are a direct swap under a jeep when run with chevy style brake hoses. It is highly reccomended to cut and turn the knuckles on these axles to acheive a halfway decent pinion angle while having a safe and acceptable caster. You can get away with not doing this if you keep a relatively low lift height. J-10s have lockign hubs while the waggys do not, but its just a bolt in affair to convert the waggys to lockouts.

The only option for a High pinion dana44 lies in the 70's ford dana44's. these come wide (67" wms) many earlier models come with drum brakes and the later models come with the cast radius arm wedges which are hard to add link mounts around. There is a sweet spot around the 1977 model year which gets you welded wedges and discs but good luck finding one. Those are found in the f-150's. To narrow these these many just cut the drivers side tube and run a shorter shaft.

the f-250's were leaf sprung and became high pinion somewhere in the late 70's, these were 8 lug and easy to work around.

Rubicon 44's are another option, direct bolt in to a zj/xj/tj (iirc) but not a true 44, it's basically a dana30 with a dana44 centersection and 30 spline inner shafts.

The jk44's are a new option out there, not a direct bolt in, but still a stout axle. high pinion, these come with 32 spline shafts, spicer 1350 sized u-joints. they have an odd 5 on 5 bolt pattern, but wheel adapters are made to alleviate this. These are relatively new and i have heard a few reports of the tubes cracking and breaking, hopefully dana/chrysler will work this issue out as the new model year arrives, but until then i say you can put a stout truss on it and not have to worry. These also require a new yoke or an adapter to run as they come stock with some screwy driveshaft setup i havent looked into yet.


im takins a break for now will add later

[Rico]

thank you sir... more rep 4 u

[XJLI]

4.88s are now available for 8.25s son.

[Mike]

also sam. you have rear Dana44 (33 and 35 spline) 36" tire max.
you have front (when built properly) 37" tire max. Safe to assume a 33 spline rear 44 can run 37s?

Also you should explain the difference between full float and semi float for those who dont know

[Jeep Creep]

also maybe include locked and unlocked?

[grundlepunch]

nitpickers jeeeez

[DrThunder]

Originally Posted by Mike

also sam. you have rear Dana44 (33 and 35 spline) 36" tire max.
you have front (when built properly) 37" tire max. Safe to assume a 33 spline rear 44 can run 37s?

Also you should explain the difference between full float and semi float for those who dont know

That's because a rear axle is subject to more stress considering the fact that it always has a majority of the weight on it when climbing obstacles and from the weight transfer of the jeep actually driving/accelerating. That's why trucks will come with dana 44 front and dana 60 rear. The rear in all cases is greater than or equal to the front.

[Mike]

explain semi or ff

[Lycaon]

semi float is where the axleshaft rests on bearings on the end of the axle tube, whereas full float is where the axleshaft is independant of the wheel bearing and is bolted by a flange to the rotating assembly, therefore allowing the removal of the shaft without disassembling the rotating assembly in the event of axleshaft failure

[Lycaon]

[Riot]

Great thread, dont know how I missed this.

[ninetysix-ex-jay]

I give you 2 thumbs up on this thread

[Saharicon]

Some more D60 infor for you.

These are the non desirable D60s


74-75.5 Ford low pinion drivers side closed knuckle drum brake with 30 spline inners, 19 spline outers, small ujoints and weak knuckles.

75.5-77 Ford low pinion drivers side open knuckle disc brake 30 spline inners, 19 spline outers, outer knuckle spindle pilot hole is smaller than 78+ axle and is therefore notched to allow 1480 series U-joint tp pass through.

94+ Dodge drivers side low pinion CAD unit bearing hub 32 spline 1.31” coil sprung Dana 60s

Any other closed knuckle Dana 60, like those from a Jeep M715 that had coarse spline axles



and another little fun fact for everyone just cuz in my research I have seen this question asked 1 billion times.

ALL GM FRONT D60s ARE PASS. DROP!



***DISCLAIMER*** I am no subject matter expert in any area, I have just been doing tons of research the last two months on axles for my jeep so I thought I would help Samual out and put my 2 cents in.

[Saharicon]

Originally Posted by Lycaon

semi float is where the axleshaft rests on bearings on the end of the axle tube, whereas full float is where the axleshaft is independant of the wheel bearing and is bolted by a flange to the rotating assembly, therefore allowing the removal of the shaft without disassembling the rotating assembly in the event of axleshaft failure

Also, in a full float axle the axleshaft only transmits the rotational torque from the differential out to the wheel. It does not carry the weight of the vehicle like a semi-floater does.

[Arundlemcbrundle]

did not know yj 30's went as deep as 5.89 . . . hrmmmmmmm