Vibration 10-15mph after adding more caster. Why? (2 Viewers)

[lasoundguy]

front is installed as it came from toyota, so out of phase im pretty sure.
View attachment 2521739

look how clean that driveshaft is!

 

[richardlillard1]

front is installed as it came from toyota, so out of phase im pretty sure.
View attachment 2521739

Put it in phase and see if it makes a difference. I had that same issue when I installed the superior engineering arms and I’ve seen other 80s go through the same thing after caster is added.

 

[Surfdc]

Put it in phase and see if it makes a difference. I had that same issue when I installed the superior engineering arms and I’ve seen other 80s go through the same thing after caster is added.

Ok. Going to properly grease the joints and shaft. Then I’ll reinstall it in phase and report back.
thanks for the feedback

 

[Surfdc]

Update:
Greased and remounted the front driveshaft “in phase” and that got rid of the vibration at 10-15 mph!

But the “whrrrrrr” at 40mph is worse.
Thoughts?

 

[richardlillard1]

Update:
Greased and remounted the front driveshaft “in phase” and that got rid of the vibration at 10-15 mph!

But the “whrrrrrr” at 40mph is worse.
Thoughts?

I’m assuming this is when the gears are in float, so between drive and coast?

 

[Surfdc]

I’m assuming this is when the gears are in float, so between drive and coast?

Just drove it to see and in float, or coasting at 40-45mph it is a very faint “whrrrr” then accelerating through 40-45 is turns into “MMMMMMMMMMMMM”

 

[lasoundguy]

Apologies for no update from me, I had a rough go of it yesterday. One u joint down one more to go. At least the new one went in quite easily.
(The grinder felt like a form of defeat but I was tired after about 90 minutes of fighting the cross to seat back the other way to get the second races out on each side.)

 

[tacocat]

Just drove it to see and in float, or coasting at 40-45mph it is a very faint “whrrrr” then accelerating through 40-45 is turns into “MMMMMMMMMMMMM”

Revert the driveshaft to out of phase. You have three choices.

1. Live with the 10-15 mph vibration.
2. Try a DC Shaft.
3. Convert to part time.

 

[Surfdc]

Revert the driveshaft to out of phase. You have three choices.

1. Live with the 10-15 mph vibration.
2. Try a DC Shaft.
3. Convert to part time.

Thanks tacocat
I suppose a 4th option is to go back down to a 2 or 2.5 inch lift and less castor, thus less pinion angle ...

 

[richardlillard1]

Both of these sound like typical NVH to me. Mine has had the sound in float for years, if I had to guess based on the times I’ve had the front driveshaft removed, it’d in the transfer case and not the driveshaft.

The”m” sound you describe could be a bearing howl. Several 80s with stock gears I’ve driven seem to have a howl from the front diff. Mine did it too before I installed new gears and bearings. In one 80 we put thicker gear oil in and the sound got somewhat quieter, but’s definitely still there.

 

[Surfdc]

Both of these sound like typical NVH to me. Mine has had the sound in float for years, if I had to guess based on the times I’ve had the front driveshaft removed, it’d in the transfer case and not the driveshaft.

The”m” sound you describe could be a bearing howl. Several 80s with stock gears I’ve driven seem to have a howl from the front diff. Mine did it too before I installed new gears and bearings. In one 80 we put thicker gear oil in and the sound got somewhat quieter, but’s definitely still there.

It could be. But again, it only started after adding the radius arms....

 

[tacocat]

It could be. But again, it only started after adding the radius arms....

I’m of the opinion that it’s pinion angle harmonics due to the fact that this is similar phenomenon amongst lifted radius arm vehicles.

Your vibration at the 10 -15 mph zone is most likely harmless, but is probably beyond irksome.

 

[Surfdc]

I’m of the opinion that it’s pinion angle harmonics due to the fact that this is similar phenomenon amongst lifted radius arm vehicles.

Your vibration at the 10 -15 mph zone is most likely harmless, but is probably beyond irksome.

I am going to agree with you.

Last night I reinstalled the front shaft “out of phase” and am back to a vibration at 10-15mph and a nice “mmmmmwhrrrrrr” at 40-45mph. Since this is my DD and my commute is through town, most of my speeds are in this range, stoping and then slowing and accelerating through lights, yes it is BEYOND irksome. Especially when it was fine before the lift.
I’m over it, I don’t have time to be under the truck f@ing with drivrshafts every other night and running around getting alignments.
-rant over-
So, going to try a dc driveshaft. If that doesn’t work, I’m going to a lower lift with less castor.
Dave @Delta VS has been super cool and helpful and will swap out the 4” arms for the 2” arms if this is the path I take.
Thank you all for your help and I will post updates as I move forward.

 

[tacocat]

I am going to agree with you.

Last night I reinstalled the front shaft “out of phase” and am back to a vibration at 10-15mph and a nice “mmmmmwhrrrrrr” at 40-45mph. Since this is my DD and my commute is through town, most of my speeds are in this range, stoping and then slowing and accelerating through lights, yes it is BEYOND irksome. Especially when it was fine before the lift.
I’m over it, I don’t have time to be under the truck f@ing with drivrshafts every other night and running around getting alignments.
-rant over-
So, going to try a dc driveshaft. If that doesn’t work, I’m going to a lower lift with less castor.
Dave @Delta VS has been super cool and helpful and will swap out the 4” arms for the 2” arms if this is the path I take.
Thank you all for your help and I will post updates as I move forward.

The DC should solve your issues. With it, you can experiment with coil spring spacers to eliminate vibes and feedback.

If you were a highway speed commuter, the part time is really nice. IME, my 80 series seems to protest going over 70 mph. It will do it, but it will let you know it doesn’t care for it.

In 2WD, it’s silent and smooth. It can cruise 75 - 80 mph without complaint. This is based only on the observations on my rig.

Now where to find a front DC driveshaft.....

 

[Surfdc]

The DC should solve your issues. With it, you can experiment with coil spring spacers to eliminate vibes and feedback.

If you were a highway speed commuter, the part time is really nice. IME, my 80 series seems to protest going over 70 mph. It will do it, but it will let you know it doesn’t care for it.

In 2WD, it’s silent and smooth. It can cruise 75 - 80 mph without complaint. This is based only on the observations on my rig.

Now where to find a front DC driveshaft.....

Good to know about the pt kit. I just dont want to have to go down that road.
Gonna get a dc driveshaft from @landtank
Gonna pull the front driveshaft and run with cdl locked until it comes.

 

[tacocat]

Let us know how it goes. The only other detailed thread in recent memory that deals with front driveshaft vibration was a paticularly tough one where the OP even tried a dual DC driveshaft.

Hopefully Mr. Tank has driveshafts ready to go.

Driving a lifted 2WD 80 was misery until I installed the Delta trackbar lift bracket.

 

[Surfdc]

Let us know how it goes. The only other detailed thread in recent memory that deals with front driveshaft vibration was a paticularly tough one where the OP even tried a dual DC driveshaft.

Hopefully Mr. Tank has driveshafts ready to go.

Driving a lifted 2WD 80 was misery until I installed the Delta trackbar lift bracket.

Rick said it will be a couple weeks. Until then I'll just run without the front shaft.

 

[lasoundguy]

Just an update, got new U-joints into my original front driveshaft and went for a test-drive...no crazy vibes to speak of but I'm still getting the "grr" on slack throttle above about 45mph. It's less than it used to be, so I can see replacing the U-joints made some difference, but it seems a DC front shaft is likely in my future as well.

Performance Driveline quoted me about $400 for a DC shaft (recommended by some local mudders when I asked) but I haven't dug in to figure out if that's directly comparable (i.e. yoke to yoke) with what @NLXTACY offers. I'll deal with it in the new year and see how frugal I feel like being vs going the easy route and supporting Wit's End (which I certainly did a lot of this year!)

 

[tacocat]

The grr on the removal of torque indicates DC from what I understand. If you wheel with those local mudders frequently, run what they brung.

Interchangeable drivelines all around.

 

[Surfdc]

Just an update, got new U-joints into my original front driveshaft and went for a test-drive...no crazy vibes to speak of but I'm still getting the "grr" on slack throttle above about 45mph. It's less than it used to be, so I can see replacing the U-joints made some difference, but it seems a DC front shaft is likely in my future as well.

Performance Driveline quoted me about $400 for a DC shaft (recommended by some local mudders when I asked) but I haven't dug in to figure out if that's directly comparable (i.e. yoke to yoke) with what @NLXTACY offers. I'll deal with it in the new year and see how frugal I feel like being vs going the easy route and supporting Wit's End (which I certainly did a lot of this year!)

Thanks for the update. Sounds like our rigs are having the same issues.
Did you ever run without the front shaft to see if vibes went away?