The only real play i see with it in neutral is in the video below.
View attachment 20250204_144816.mp4
View attachment 20250204_144816.mp4
CK5
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Long standing pulsating vibration issue that I need help solving
- Thread starter Ramba_ral
- Start date
You need to measure angles front to back not side to side
yesAlright.
looks like transfer case side is 5 degrees pointing down
drive shaft is 17 pointing up to the transfer case
rear end is 15 pointing up to the transfer case
following this example the cv joint op angle is 12
and the pinion joint op angle of 2
Assuming the rear end kicks up about 2 degrees under acceleration that would put it at 0?
looks like transfer case side is 5 degrees pointing down
drive shaft is 17 pointing up to the transfer case
rear end is 15 pointing up to the transfer case
following this example the cv joint op angle is 12
and the pinion joint op angle of 2
Assuming the rear end kicks up about 2 degrees under acceleration that would put it at 0?
in my mind the pinion should be 26° lower then shaft not above, from your drawing. With the double cardan cv really doesn't matter what angle the t case is for the rear. More important for front shaft.
really can't get accurate measurement on the um machined parts of the yoke. The 2 middle diff cover bolts would be more accurate for a quick rough ball park. Best way is to unbolt the shaft and measure angle across the yoke, on one u joint saddle.
That t case output bearing has enough slop to cause a vibration.
really can't get accurate measurement on the um machined parts of the yoke. The 2 middle diff cover bolts would be more accurate for a quick rough ball park. Best way is to unbolt the shaft and measure angle across the yoke, on one u joint saddle.
That t case output bearing has enough slop to cause a vibration.
That looks like the are to much splines showing to me. How much are the splines inserted into the slip yoak? Will that move up and down (axial) Is the driveshaft being checked with that much spline showing or is it slid together more when being checked? If that moves at all ,it could vibrate like a bent driveshaft under a load.
If all of that checks out, post a picture of the front "bull" bar.
I had a guy with a Bronco complain about the same thing. Only above 60mph. I went through everything. Put a piece of carboard over the brush guard and it went away. He sold the brush guard.
I had a guy with a Bronco complain about the same thing. Only above 60mph. I went through everything. Put a piece of carboard over the brush guard and it went away. He sold the brush guard.
It's not unusual to get some harmonic vibration that happens only in 3rd gear (well, whatever gear is 1:1). There's something about the engine and drivetrain all being locked together at the same speed. If that's the issue, an overdrive transmission would solve it (and honestly, sustained 65+ MPH without overdrive isn't a great setup unless you gear it to be a dog.) When this truck was built, the national speed limits were 55MPH. The easiest solution is to slow down 
. I'm curious what gear ratio you have, because the taller the gears, the slower the drivetrain is going. If the issue was with the fan or balancer, it should happen at the same RPM in 1st and 2nd gears.
Some other easy checks are to raise each corner and spin each tire by hand to check for a bent axle flange or wheel, out of round wheel, etc. A dial indicator is the best way to check, but you can also place fixed objects near the item you're measuring in such a way you can eyeball the gap and see if it's changing.
If you have access to another set of wheels and tires in a different height, you could figure out if it's the wind speed or driveline speed that sets it off. You'd probably want to use GPS for speed in both setups.
. I'm curious what gear ratio you have, because the taller the gears, the slower the drivetrain is going. If the issue was with the fan or balancer, it should happen at the same RPM in 1st and 2nd gears.Some other easy checks are to raise each corner and spin each tire by hand to check for a bent axle flange or wheel, out of round wheel, etc. A dial indicator is the best way to check, but you can also place fixed objects near the item you're measuring in such a way you can eyeball the gap and see if it's changing.
If you have access to another set of wheels and tires in a different height, you could figure out if it's the wind speed or driveline speed that sets it off. You'd probably want to use GPS for speed in both setups.
I don't think it's his drawing, so the numbers in the drawing should be replaced with the ones he typed, and they seem pretty decent.
@Blue85 I have heavily considered a 700r4 or a 4l60e swap. Right now it has 3.73 gears on 35s At 65mph im sitting around 2600-2700 rpm. 3k~ at 75
i have a spare set of rims but not a smaller set of tires to test.
as for the check you mentioned. they all seem to be fine and even. one of the reasons I had the rear end rebuilt was one of rear axles was bent.
i have a spare set of rims but not a smaller set of tires to test.
as for the check you mentioned. they all seem to be fine and even. one of the reasons I had the rear end rebuilt was one of rear axles was bent.
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That one is not and issue. The flat bar or screened ones will flutter.
Still want to see the pinion pointed down at least 1° from drive shaft slope. When you accelerate the pinion will move up 1 or 2°. maybe I'm not getting the angles correct in my mind but 28° seems to above the drive shaft slope.
assuming i took the measurements right yes
looks like transfer case side is 5 degrees pointing down
drive shaft is 17 pointing up to the transfer case
rear end is 15 pointing up to the transfer case
following this example the cv joint op angle is 12
and the pinion joint op angle of 2
Assuming the rear end kicks up about 2 degrees under acceleration that would put it at 0?
looks like transfer case side is 5 degrees pointing down
drive shaft is 17 pointing up to the transfer case
rear end is 15 pointing up to the transfer case
following this example the cv joint op angle is 12
and the pinion joint op angle of 2
Assuming the rear end kicks up about 2 degrees under acceleration that would put it at 0?
