Devbot
New member
Hi all,
So quick backstory; had a vibe with throttle only after I installed my lift. It would come around 40-50 strongest and most reliably but sometimes it would happen much lighter at lower speeds, usually starting as an oscillating "wub-wub-wub" sound that would steady out. Only with throttle; would cut out the second you let off. Figured it to be bad u-joint(s), so I replaced my driveshaft which helped but didn't solve the problem - come to find one of the u-joints they used was crap and had very obvious play in it, to the point where the driveshaft would clunk if pushed just right. The bad joint in question was in the rear, at the slip yoke/third member.
I put up with it for a while until recently tackling it again, and replacing the joint with a brand new one from Spicer; now I still have the vibration, but it's even worse than before. Doesn't oscillate so much, but definitely louder than before - still same symptoms as before, happening worst at ~50mph and ONLY with gas, seemingly around 1500RPM and over. Happens in both 2WD and 4WD. Feels and looks like I'm driving a subwoofer when I look in the mirror. I have attached a video of it happening though it might be hard to hear without headphones on. (Before anyone says so, I was on my way to the gas station while recording this!)
After replacing the joint the play I noticed was gone but pushing on the driveshaft the clunk was still there, just greatly diminished. I have a feeling at least one of the u-joints in the double cardan is probably also faulty (and if they used 3 from the same batch like it seems, it's probably a safe assumption)
With all that said, I'd love to hear anyone's input on this. I'm fairly confident it's either a bad pinion angle or u-joint, but I've never experienced a bad pinion angle before so I'm not sure what to look for in that regard; if that's where I should start looking, how does one check their angle, and is there a good number to shoot for? I tried looking for a missing balancing weight on the prop shaft and didn't see anything missing. To add to this my third member has been replaced before and the oil looked fine when draining it last year so I highly doubt it's the pinion bearing/diff itself wearing out; and the fact that the sound has changed/altered as I messed with the driveline leads me to believe I'm on the right track. Regardless a second or third opinion would still be appreciated here. Buddy of mine is adamant it's the trans, but it doesn't seem that way to me - I would imagine it to be much more constant with much worse symptoms if so. I tried to include anything I thought would be handy, but if I missed any information let me know.
<iframe width="560" height="315" src="https://www.youtube.com/embed/8k_UF2FOTMk" title="YouTube video player" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>
So quick backstory; had a vibe with throttle only after I installed my lift. It would come around 40-50 strongest and most reliably but sometimes it would happen much lighter at lower speeds, usually starting as an oscillating "wub-wub-wub" sound that would steady out. Only with throttle; would cut out the second you let off. Figured it to be bad u-joint(s), so I replaced my driveshaft which helped but didn't solve the problem - come to find one of the u-joints they used was crap and had very obvious play in it, to the point where the driveshaft would clunk if pushed just right. The bad joint in question was in the rear, at the slip yoke/third member.
I put up with it for a while until recently tackling it again, and replacing the joint with a brand new one from Spicer; now I still have the vibration, but it's even worse than before. Doesn't oscillate so much, but definitely louder than before - still same symptoms as before, happening worst at ~50mph and ONLY with gas, seemingly around 1500RPM and over. Happens in both 2WD and 4WD. Feels and looks like I'm driving a subwoofer when I look in the mirror. I have attached a video of it happening though it might be hard to hear without headphones on. (Before anyone says so, I was on my way to the gas station while recording this!)
After replacing the joint the play I noticed was gone but pushing on the driveshaft the clunk was still there, just greatly diminished. I have a feeling at least one of the u-joints in the double cardan is probably also faulty (and if they used 3 from the same batch like it seems, it's probably a safe assumption)
With all that said, I'd love to hear anyone's input on this. I'm fairly confident it's either a bad pinion angle or u-joint, but I've never experienced a bad pinion angle before so I'm not sure what to look for in that regard; if that's where I should start looking, how does one check their angle, and is there a good number to shoot for? I tried looking for a missing balancing weight on the prop shaft and didn't see anything missing. To add to this my third member has been replaced before and the oil looked fine when draining it last year so I highly doubt it's the pinion bearing/diff itself wearing out; and the fact that the sound has changed/altered as I messed with the driveline leads me to believe I'm on the right track. Regardless a second or third opinion would still be appreciated here. Buddy of mine is adamant it's the trans, but it doesn't seem that way to me - I would imagine it to be much more constant with much worse symptoms if so. I tried to include anything I thought would be handy, but if I missed any information let me know.
<iframe width="560" height="315" src="https://www.youtube.com/embed/8k_UF2FOTMk" title="YouTube video player" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>
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