Drive shaft vibration? (1 Viewer)

[tarpaigh]

I have a vibration from my back end in 3rd gear (3speed transmission) that goes away when I push the clutch. The phasing on the driveshaft I thought was correct. Should I remove the driveshaft and take it to someone for balancing? There seems to be a weight on one side. Is there something else I should do? Thank you for the help.

 

[Broski]

Well If you put the clutch in and your still moving the driveshaft is still turning. kinda rules out the driveshaft
Is there no change coasting with the clutch engaged.
Is this a new setup ? The pinyon angle seem off pointing to high up.

 

[charliemeyer007]

Interesting. The weight is the balance adjustment - I have never seen 2 on one shaft.

You might try checking your tranny/transfer fluid level.

The phase looks odd to me but I'm no pro

 

[pb4ugo]

I agree the pinion looks like it's pointing up too much. What's the history of this setup? What year, model and origin of this vehicle? The perches don't look stock.

 

[3_puppies]

rear diff has been changed or atleast the flange, 2 different style of Ujoints.
x alot on the diff angle
sure looks like the ubolts are at an angle
wonder how much of the slip yoke is engaged??
at the angle of the diff, seems like the pinion is up out of the oil level

more pics and investigation needed before driving it anymore

 

[Paul_A]

The angles are not good. Grab the diff flange and jerk it around, up, down, in, out, side to side and look for movement.

 

[majdomo]

That slip yoke looks barely engaged. There should be about 1.5" of the last part of the slip yoke showing - you can see it in the photo, the gold-ish unpainted bit should be down in the slip spline of the driveshaft. Agree pinion angle looks way off. Check for torque on pinion nut and flange when the driveshaft is off.

 

[Mike Shull]

You can have a driveline vibration from misaligned angles that goes away when you depress the clutch and disengage the power to the driveline. In this case, most likely what is happening is that under load your shifting the pinion upwards, causing your drive line angles in your case to worsen.

As others have said, I would fix your driveline angles first. You will want equal and opposing driveline angles on that type of setup.

I zoomed in on your right rear leaf spring and it looks like it has a wave in it. Is this just the angle of the camera?

 

[tarpaigh]

Not a new build so I wasn’t sure why it developed. It completely goes away when the clutch is engaged. I will check the transmission fluid level. The pinion angle didn't end up what it should be with new springs/axle. I bought the axles from a later model to get the disc brakes. We reused the old driveshaft but changed the u joints. I was trying to get this drive-able for my son's parade tonight.

 

[pb4ugo]

A later model with disc brakes? From what model Land Cruiser? 40's didn't come with disc brakes. How long has it been driven with this setup. Because of the really high pinion angle, you've put a lot of stress on the pinion bearings and u joints. Check them 1st. If they're ok, then I'd address the pinion angle. The tcase output and pinion need to be horizontally parallel to each other to eliminate vibration. To correct the pinion angle you might be able to use shims. The angle looks really extreme and I'm not sure shims will work. If the shims don't wirk you'll have to cut the perches off and rotate the axle housing. Once the pinion angle is corrected, then weld the perches to the housing. The pinion angle is most likely causing the vibration.

 

[peesalot]

Put some 2 degree shims under the perches to kick pinion down, get the driveshaft retubed to proper length, in my exp the rattle you hear is from the slip spline and others are correct you only have 1.5" of engagement if that. It looks like you used the tube side of the later year and the slip yoke from earlier year to make drive shaft so u-joints would work which is fine, its just too short. x4 on check trans fluid, make sure earl is not transfering from tcase to trans or vise versa, I cant remember which one fills sometimes when the seal between goes.

 

[3_puppies]

Not a new build so I wasn’t sure why it developed. It completely goes away when the clutch is engaged. I will check the transmission fluid level. The pinion angle didn't end up what it should be with new springs/axle. I bought the axles from a later model to get the disc brakes. We reused the old driveshaft but changed the u joints. I was trying to get this drive-able for my son's parade tonight.

more pics needed, I wouldn't drive it right now, but that is me
what axle did you install?
what springs? is the military wrap on the fixed end of the spring?


good news is the driveshaft is in phase

 

[tarpaigh]

The axles are from a 1976. I put some shims under the rear. Here is a new picture. I took it for a spin. Still has some rattle above 30 mph but seems better.

 

[pb4ugo]

What dergree shims are those? It's better and the slip joint looks better too. You can go to the hardware store and get a cheap angle finder and measure the pinion and tcase output flange angles. Park it on level ground. You can get on tom woods driveshaft and read driveshafts 101 or something like that. You'll understand what you're trying to do.

 

[jim land]

No extra tall shackles on the rear ?

 

[3_puppies]

wonder if the mounts welded to the axle are off
they look non stock and looking at where the wheel cylinder is located, it looks higher up than it should be it looks like 10 o'clock and it should be more at 9 o'clock

 

[peesalot]

Those perches are whack, curious about rear shackle length as well

 

[pb4ugo]

I think the perches aren't stk, and look to be aftermarket. I'd guess the axles came from a lifted 40 that ran a double cardon joint. That would explain the pinion angle. If it requires more than a 4* shims and you like the suspension and tires, then I'd consider cutting the perches off and correcting the angle with no shims. He needs to measure the angles to see where it's at 1st.

 

[tarpaigh]

Thank you for the help. With the advice here, I was able to fix a number of problems and ultimately get the vibration to stop. The last thing I did was top off the transfer case fluid which was low. After I did that, it stopped. Transmission fluid was fine. But now there is no more rattle. I have no idea why the fluid level was low. I am really impressed with all that was identified from my picture and grateful for the help on this forum.