It is hard to tell since we can't see both ends of the driveshaft at the same time. Take a look at post #6 in this thread. You will see that the sleeve yokes will be aligned, this is in phase. If they are not aligned then taking off one end and simply rotating it until they are in alignment before sliding the shaft back together.
High 3rd gear, low 4th gear vibration (1 Viewer)
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- Thread starter
- #42
All of the yokes appear to be aligned - the section before the transfer case and the one in the rear after the transfer case as well.
- Thread starter
- #44
Now that I have a better idea of what I'm looking for, maybe a straight on shot of the shaft would be more helpful to everyone -
Wow, that's the first time I actually saw how short the 40 prop shaft is.
Fair enough. My bad. They looked out of phase to me, even with the right photos, but obviously I was wrong!
That's great news, but also sucks because you don't have a fix for your problem.
My grease gun is a bit tight in those joints too - it only fits if the joint is exactly in the right place, try rolling it forwards a few inches.
I add a photo of my 45 Prop shaft fwiw - tons of space underneath
Fair enough. My bad. They looked out of phase to me, even with the right photos, but obviously I was wrong!
That's great news, but also sucks because you don't have a fix for your problem.
My grease gun is a bit tight in those joints too - it only fits if the joint is exactly in the right place, try rolling it forwards a few inches.
I add a photo of my 45 Prop shaft fwiw - tons of space underneath
That is in phase , that’s a good sign.
micruz60
Unleaded Regular
It appears to me that the rear differential / pinion is not pointing / aligned to the angle of the driveshaft / propeller shaft, a common issue due to a lift.
- Thread starter
- #48
Interesting point. You'd normally rotate the axle upwards would you?
How about the handbrake end - looks even worse to me.
Loading up the truck with a bit of weight in the back should help, right?
micruz60
Unleaded Regular
The shim would be recommended on the rear axle where it sits on the spring perches, tilting the differential to align to the driveshaft.
micruz60
Unleaded Regular
Here’s a picture of the driveshaft on my 40, I do not get much vibration when going up to 50 mph, above that it’s wind resistance and front axle noise that gets my attention. 
The rear axle does not have any shims, and the differential is mostly horizontal in relation to the driveshaft.
The rear axle does not have any shims, and the differential is mostly horizontal in relation to the driveshaft.
Do you have similar lift do you think?Here’s a picture of the driveshaft on my 40, I do not get much vibration when going up to 50 mph, above that it’s wind resistance and front axle noise that gets my attention.
View attachment 3419844
The rear axle does not have any shims, and the differential is mostly horizontal in relation to the driveshaft.
micruz60
Unleaded Regular
I’m running a three inch lift.
- Thread starter
- #54
Since you are running a lift with no shims, how are you able to keep that angle from your drive shaft to the diff straight?
micruz60
Unleaded Regular
The drive shaft and pinion shouldn’t be in a perfect plane unless you’re running a double Cardan. When running one of those you point the differential directly at the transfer case. Since your running a stock setup you likely will need to adjust the pinion down not up. Unfortunately this is just a guess till you take off the shaft and check the piñon angle and transfer case angle, you want these to be within 2 degrees of each other.
Agreed, the pinion looks angled up too high. And under load would go higher.
Just re-reading this and checking that I understood correctly...
Did you mean that the vibration stops when you push down on the clutch (at say 40mph)?
- Thread starter
- #59
Yessir, took it back out after lubing the zerks along the drive shaft and I think I'm gaslighting myself, the vibration seems a tiny bit better but it's still bad.
To answer your question though, yes if I push the clutch in, the vibrations go away like "the issue" is being disengaged.I can definitely tell when I accelerate I can "feel" it ramp up as the truck pulls thru the gear.
Aha interesting. So you get it both on the gas and off the gas, and cruising at 40 (?), but not with the clutch pushed in.
I see a drop of fluid on the transfer drain plug - all your fluids are topped up I assume? (Gearbox, transfer, differentials).
