Shawn;
I agree with the statement, except the part which says ALL front axles are FF. Now thats true for Dynatrac, they only sell FF front axles. I have just mentioned higher up in this topic that during the 70s Dodge used semi floating Spicer 44 axles on their full time 4x4s. Before that, all Dodge military Power Wagons were also equipped with Spicer semi floating front axles.
Full time front axles became standard equipment because they were stronger, and could be made lighter without loss of strength, and they were safer. One big advantage for FF was the ability to have a means to engage and disengage the axleshaft from the hub flange, (via a lock-out hub) making it possible for true part time 4wd. This is impossible for a semi floater unless there is a conversion to FF.
With the introduction of all wheeldrive, and CAD systems, , semi floaters are making a come back. There is no longer a need to disengage the axleshafts from the hub flange. AWD works much like full time 4wd except they are capable of constant use on pavement. Since the axles are always engaged to the hub, there is no need to use a FF axles. Many CAD systems make use of SF axles, but engage 4wd by locking in two halves of a common shaft. The axles still are permantly engaged to the wheels. Although the means of CAD engagement is failure prone, CAD is reported to be stronger than lock-out hubs. Currently SF axles of these types are IFS.
Ed
On 2002-01-16 18:49, shawn bentley wrote:
this was taken from Dynatracs website. i think they would know their axles!
Full-Floating vs. Semi-Floating
Any drive axle must be capable of performing two functions: Support the weight of the vehicle safely and transmit power to the wheels for propulsion. By design, all steering (front) drive axles are full-floating, but rear drive axles may be semi-floating or full-floating.
this website will also clearify somethings.
http://www.off-roadweb.com/archives/tech/1201_tech02.shtml