Weird Vibration

BlueWaffle · Jul 2, 2013

I noticed yesterday that my truck would get a high frequency vibration/shudder at around 45 mph+. It does not seem RPM dependant so I don't think motor but when I am on the throttle @ 45+, the vibration is there. If i let off and coast at 45+ the vibration goes away. so something in the drivetrain? I am missing some balance weights on one of the wheels but if that was it, it shouldn't matter if it is under power or coasting so I'm not sure. sound transmissionish? again, seems dependant on power input at 45+ mph.

FATHERFORD · Jul 2, 2013

check the drive shaft.

BlueWaffle · Jul 2, 2013

driveshaft is tight and pinion is solid BUT i noticed that there is rear end oil slung all over the fuel tank and exhaust. it seems like it's been there for a while but I'm wondering if this is a rear end issue. no play in u joint though...

bottom of pinion

BlueWaffle · Jul 2, 2013

ok i put the truck on stands and took it up through the gears to try to pinpoint the vibration. the pinion has a little bit of axial play but not much. fast forward to about 50 sec in the vid and watch/hear what happens. it did this several times before i got the camera on it also. rear diff fixing to implode on itself?

not the smartest way to test but it's all i could do...truck was on jack stands not pictured...wasn't resting on the jack itself

ghohouston · Jul 2, 2013

Maybe change rear end fluid, and add friction modifier, and also, grease the slip joint on the drive shaft

florida 6.0 · Jul 2, 2013

My truck has had a vibration at 45 since it was new . Its an 05 . I have tried multiple threads on multiple sights and it seems to have started in 1999 and no one has found a fix for it . Ford has a counter balance you can by but I have not found any one with one to see if it works or not . My fix is to go 40 or 50 mph .

BlueWaffle · Jul 2, 2013

Did you guys not hear see what happened in the vid @ 50 sec and 1:10??

Also, no slip joint in driveshaft. Custom 1 piece shortened shaft

ghohouston · Jul 2, 2013

I saw no video to watch, and I see, maybe driveshaft isnt properly balanced? My company gets all their manual trannys and rear ends rebuilt at ft worth gear and axle, and we have seen some shotty work come from them