Propeller Shaft U-Joint Phasing

Propeller Shaft U-Joint Phasing


this is a demonstration of how to check or drive shaft phasing or propeller shaft phasing though some manufactures call it phasing of the u-joints is critical to make sure that second-order vibrations do not occur second-order vibrations are vibrations that have two shakes per revolution of the propeller shaft or drive shaft so we’re looking here at the front drive shaft propeller shaft of a 2007 Toyota Tundra here’s the front differential and the transfer case the rear propeller shaft in two pieces and the rear differential will appear on the front propeller shaft we have two u joints and to check for phasing proper phasing of the u joints you need some sort of an inclinometer tool and there are many smartphone applications that have an inclination what the phasing of the u-joints means is is this u-joint cap lined up with this u-joint cap are they perfectly in line with each other or not so what we do is we’ll come in with an inclinometer and we’ll measure 2.3 degrees and then without moving the propeller shaft we’ll come to the back u joint and if this propeller shell is put together properly we should have the same angle measured back here so I’ll get it as close as I can in the same location we’ve got to well we’ve got three degrees back here so we had to point come back up to the front here double-check that well there we go I musta bump it to point nine on the front three degrees on the back those two are very close to being equal the phasing specification is no more than plus or minus three degrees from the front you joint to the rear meaning that if the propeller shaft were twisted the maximum amount it could be twisted would be three degrees now obviously the closer that is to being zero the better off your propeller shaft is going to be in the less likely it is deal that you will end up with the vibration now you as a technician can actually cause these to be out of phase if you’re not careful and that is right here on the front propeller shaft and on rear propeller shaft sometimes there’s a slip yoke and the slip yoke is under this rubber bellows here but it has a bunch of splines and if for some reason that front or this rear piece gets pulled out of the front piece and you just slide it back in any old way that it’ll go you could set up as a second-order propeller shaft vibration two shakes per revolution if this u-joint bearing cap is not lined up with this bearing cap so they need to be lined up and you need to watch that to make sure that you’ve got them lined up when you put it together now here on the rear propeller shaft we’ve got three u joints and we’re going to measure the angles of all of those so let me come around here to the other side where it’s a little easier to to see and we’ll come in with our in klonoa so I’m laying that in klonoa right on the u-joint cap you could do this from underneath the vehicle focus there there we go 0.2 degrees so in the truck obviously you’re going to be putting the in klonoa underneath where here I’m putting it putting it on top it doesn’t matter whether it’s on top or underneath just wherever you can get it to fit so we had zero Oh point two on that rear u-joint zero point six point seven on this middle u-joint and once again here is a slip yoke there’s splines in here and if you ever had this come apart make sure when you put it back together that it is lined up properly the u joints are lined up with each other and then here on the front you joint our odd u joint well put the inclinometer and we are at zero point four degrees so we have zero point two at the back u joint we had zero point six in the middle and zero point four at the front as long as all of those are within the plus or minus three degrees technically it’s within specification but this is a beautiful driveshaft as far as being set up properly because all of these are equal within half a degree which is quite a challenge you try that on any other propeller shaft and I think you’ll be surprised at how hard it is to get that lined up at this isn’t definitely a well-built propeller shaft so this has been a demonstration of how to measure proper u joint phasing once again phasing means that the u joints are it’s a measurement of how closely are all u joints lined up together so as you look up the shaft here from the rim where u joint forward although u joint bearing caps need to be lined up together with plus or minus three degrees preferred of course would be zero


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