Depending on the year and cab and bed configuration, F150 pickups come with either a one-piece driveshaft or a two-piece driveshaft. It depends entirely on the wheelbase of the truck. A shorter wheelbase truck can get away with a one-piece driveshaft whereas longer trucks must use a two-piece shaft. To tell which your truck has, simply look underneath. Two-piece shafts will have an additional central support mount that is quite easy to identify.
OEM driveshaft material is mainly steel. However, some factory one-piece driveshafts are indeed made from aluminum. Determining which shaft your truck has can be done using a magnet. If a magnet won’t stick to the driveshaft, then you have an aluminum version.
It is difficult to source an exact number at which the factory driveshaft is rated to. Rather, digging through many online owner reports, it seems that the bulk of driveshaft failures are related to two scenarios: 1) driveshaft tears due to stress when off-roading (where the wheel is slipping then suddenly bites – most commonly the front driveshaft of 4WD breaks under this circumstance), and 2) seized u-joints.
Moreover, there are exponentially more complaints concerning odd driveline harshness, vibrations, or thuds through all phases of driving. These driveline symptoms have been an issue that has plagued F150 pickup trucks for multiple generations, with the real cause remaining a mystery for the most part as some trucks suffer from it time and time again whereas others go their entire life without issue. Furthermore, any problem with the OEM driveshaft necessitates replacement of the entire system (shaft, central carrier, and u-joints) as it is a non-serviceable unit.
If your truck is currently suffering from a similar driveline symptom or you want to prevent yourself from blowing a shaft out on the trail and possible becoming stranded, aftermarket units are readily available to take care of problem one and beef up problem two.