I have a 1999 F-250 Super Duty with 4.30 Limited Slip differential.
Is this a "floating" axle?
What is the difference between a floating axle and a non-floating axle?
Is a non-floating axle just called an "axle"?

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1999 F-250 XLT Super Duty Crew Cab Long Bed
V-10, Automatic 4R100, 4.30 Limited Slip.
GVW = 6700# Towing Capacity = 13,300#
4 Wheel ABS disks + Reese 15K hitch
Dark Hunter Green. Ford Running Boards.
Grey Rhino-Liner. Captain's Chairs. CD+Tape
Polished Stainless Steel Wheel-well Molding http://members.home.net/jchartier/jnctrk.html

 

Greetings!

A "floating" axle (also known as a "live" axle) means that the axle assembly (differential, shafts and brake assembly) "float" or are "live" from the driveshaft (and rest of vehicle for that mater) and are supported (most of the time) by leaf springs/shocks. In other words, if you were to jack up your truck and disconnect the driveshaft from the differential and remove the springs and shocks, the entire axle with tires and all would fall to the floor.

Compare this setup to the independant suspension systems (e.g. Explorers, most cars, etc.) where the axle may be attached to the body of the vehicle not only via the driveshaft, but through coil springs, struts, etc. All F-150/250/350's have live rear axles, and SuperDuty's have this same setup in the front, whereas F-150's (and 97-99 F-150 light duty's) have torsion bars up front.

Steve

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2000 4X4 Lariat SuperCab
5.4 Triton
Two-tone black on silver
All options except LS differential

MODS so far:

-Westin step bars (powder coated matte black)
-Lund bug shield
-Gentex electrochromatic rear view mirror
-Cabin filtration kit
-Superchip
-Stull Billet Grill
-Flowmaster Force II catback (series 50 SUV with duals out the rear)
-Line-X bedliner

MODS to come:

-K&N or AirAid FIPK kit
-Mickey Thompson Challenger 16" wheels with 295/75 BFG AT KO's
-4.10 gears (still thinking about this one ...anyone have any input?)
-LS diff or locker of some sort once they are available..
-A.R.E. LSII or Ford HarleyDavidson tonneau cover

[This message has been edited by TSSCS (edited 02-23-2000).]

[This message has been edited by TSSCS (edited 02-23-2000).]

 

Steve, Thanks for the quick reply. I understand the independent suspension (having owned a GTV Alfa Romeo in a previous life). But I'm still confused over the terms:
"Full Floating" and "Semi-Floating"...
Could you unconfuse me? TIA

 

A full floating axle is able to carry more weight than a regular axle. The weight of the vehicle and or cargo is supported by the axle housing and not the axle shaft like on a regular axle. The only thing that the axle does on a full floater is turn the wheels, while on a regular axle the axles turn the wheels and also carry all the weight because the wheel bearing is attached usually pressed onto the axle. It is hard to explain, to be so obvious. Any front axle on a 4x4 that has locking hubs is a full floating axle. I have just confused myself typing this, but I hope you can make something out of it, and hopefully someone else can explain it better.

LHM

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2000 F-150 Super Cab XLT 4x4 ORP 5.4liter V8, Towing Package, Rear Slider, Remote keyless Entry,3.55 LS, Black Exterior, Medium Graphite interior, manual shift 4x4. Current mods Gooseneck hitch, mud flaps and Y pipe with duals.

 

An example of a 'live axle' is illustrated by your garden tractor, where the axle shaft that exits the gear portion of the rear-end extends out several inches and holds the tire -- and the entire weight of the vehicle is borne by the axle shaft -- not supported out by any bearing at the wheel. The axle is free to bend as it is loaded -- sometimes actually being the 'spring' for the vehicle.

The 'semi-floating' axle is one where onto the axle shaft is 'pressed' a bearing -- and that axle itself has studs for the mounting of the wheel on that end -- and splines to go into the 'spider gears' of the differential carrier on the other. In this form, the axle bears the weight of the vehicle via the bearing which is located in the axle 'housing' close to the flange which holds the wheel.

A 'full floating' axle is one in which the hub (onto which the wheel is bolted) is supported by bearings; and the axle shafts are then connected (in our case pushed from the outside towards the differential carrier (aka 'pig' or 'chunk' or 'gearset'). No actual weight is borne by the axle shafts -- which are merely used to transmit torque from the 'rear end' gears to the 'wheel-end'. (While in the Army as mechanic trainees, two of us 'got even' with a jerk who we caught at a bar in a 'duece-and-a-half' while he was on duty. Well, since the truck had 'full-floating' axles, and since we had recently taken the thing apart as a class exercise, we disabled truck by pulling out one front and one rear axle shafts which only meant some 8 or 10 bolts that held in each -- easily handled with hand tools and a brief whack with a hammer.)

Oh, those were the days...

 

The quick way to tell if your truck is full floating or not is to pull off one of the center caps (if they just clip on) and see if the axle is sticking out. If it is then you have a full floating axle. If the axle is setting flush to the rim, then you have a semi floating axle. With the axle shaft sticking out from the wheel, it means that not all of the wait is put on the end of the shaft. My dad's F-250 Powerstroke (96 model) has a full floating axle where as my '80 model didn't.

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1999 F-250LD 4X4 XLT Supercab, Short Bed, 5.4L, AT, 3.73LS, 33"Wrangler ATS, Dual Exhaust, Custom Air Intake, Superchip, Color: Harvest Gold cc "Ready to Farm"

 

Thanks to all. These are good descriptions.