Pulsing/droning vibration at highway speeds (2 Viewers)

[fussychicken]

Out of curiosity, do you get any vibration/resonance when you're at a stop, idling in gear? I do. Goes away as soon as I drop it in neutral...

I did a while back, but it has slowly gotten better as I've installed more and more new rubber. The engine/trans mounts helped a bunch. But the front sus and rear sus bushing change got rid of even more. I still haven't gone through all vacuum hoses to see if I can get the idle speed up a touch.

I'd say it is pretty good right now, but yes it is even better when I put it in neutral.

 

[fussychicken]

So quick update on my driveshaft balance. I drove up to Sacramento so I could take them to "Drive Line Services of Sacramento" given they had the best reviews around the NorCal area.

Shop was bumping. Looks like in addition to a bunch of car work they do a bunch of industrial stuff too. Brought in both of my brand new OEM shafts and had a good chat with Mike there. We talked about phasing, slip yoke location, driveline angles, and all kinds of stuff. He said in his experience it is pretty darn rare to have a brand new OEM shaft be out of spec, but they were happy to spin it up and see what's up and then rebalance if need be. He says they shoot for 5 thousands runout.

Then he looks at me and says: "You know I used to have a 100 series." and of course I was like no way! And then he says, "it also had a vibration issue" and then I was like OMG! Tell me more! And then he said "I could never figure it out." And my jaw hit the floor.

I said "But you are the driveline expert! If you cant' figure it out, none of us can!" Then he told me I was giving him PTSD! He said he tried all kinds of stuff, then sold it to a friend who put in a new rear diff that also didn't fix the issue.

So needless to say he wasn't optimistic about my theory that the OEM shafts were out of spec.

Anyway, I pick them up on Friday. Wish me luck. lol

 

[LJE]

So quick update on my driveshaft balance. I drove up to Sacramento so I could take them to "Drive Line Services of Sacramento" given they had the best reviews around the NorCal area.

Shop was bumping. Looks like in addition to a bunch of car work they do a bunch of industrial stuff too. Brought in both of my brand new OEM shafts and had a good chat with Mike there. We talked about phasing, slip yoke location, driveline angles, and all kinds of stuff. He said in his experience it is pretty darn rare to have a brand new OEM shaft be out of spec, but they were happy to spin it up and see what's up and then rebalance if need be. He says they shoot for 5 thousands runout.

Then he looks at me and says: "You know I used to have a 100 series." and of course I was like no way! And then he says, "it also had a vibration issue" and then I was like OMG! Tell me more! And then he said "I could never figure it out." And my jaw hit the floor.

I said "But you are the driveline expert! If you cant' figure it out, none of us can!" Then he told me I was giving him PTSD! He said he tried all kinds of stuff, then sold it to a friend who put in a new rear diff that also didn't fix the issue.

So needless to say he wasn't optimistic about my theory that the OEM shafts were out of spec.

Anyway, I pick them up on Friday. Wish me luck. lol

Haha, that's less than encouraging...

One thing I've been meaning to do is throw a bunch of weight in the back (I've got some bags of concrete laying around to use), along the lines of 3-400 pounds & see if/how that changes things, since you're non-trivially changing the amount of mass in the cabin at that point. I *swear* it was worse the other day when my wife was riding with me, but that was also the first time I've had it up to highway rush hour speeds and noticed that above 73 mph the vibration/resonance SUCKS. Again though, it all seemed worse with the wife in the cabin. She does not weigh the same as 300-400 pounds of concrete, so if it's truly an issue I figure that should exacerbate the effect.

So I have symptoms from 45-52 mph, and 72-80 mph. What's interesting is that from 75-80 mph the frequency of the resonance stays at 60 hz, rather than shift with road speed as it does everywhere else (confirmed with audio spectrum analyzer app).

Not sure what to think, but that's where I'm at at the moment. Top of my list are the muffler (seems crunchy, may have weird leaks), body mount bushings, and the transmission.
The muffler and transmission though would be confusing, as the resonance occurs at the same road speed whether I'm in 4th or 5th gear, which are very different engine speeds. This entire thing is confusing though, so I'm just tossing spaghetti at walls & seeing what sticks at the moment...

 

[LJE]

So quick update on my driveshaft balance. I drove up to Sacramento so I could take them to "Drive Line Services of Sacramento" given they had the best reviews around the NorCal area.

Shop was bumping. Looks like in addition to a bunch of car work they do a bunch of industrial stuff too. Brought in both of my brand new OEM shafts and had a good chat with Mike there. We talked about phasing, slip yoke location, driveline angles, and all kinds of stuff. He said in his experience it is pretty darn rare to have a brand new OEM shaft be out of spec, but they were happy to spin it up and see what's up and then rebalance if need be. He says they shoot for 5 thousands runout.

Then he looks at me and says: "You know I used to have a 100 series." and of course I was like no way! And then he says, "it also had a vibration issue" and then I was like OMG! Tell me more! And then he said "I could never figure it out." And my jaw hit the floor.

I said "But you are the driveline expert! If you cant' figure it out, none of us can!" Then he told me I was giving him PTSD! He said he tried all kinds of stuff, then sold it to a friend who put in a new rear diff that also didn't fix the issue.

So needless to say he wasn't optimistic about my theory that the OEM shafts were out of spec.

Anyway, I pick them up on Friday. Wish me luck. lol

Any recent updates on this?

 

[dnp]

Any recent updates on this?

Watching also

 

[marcfj60]

I can't recall if I ever responded but since I'm the originator of this post I will update that my vibration/resonance went away when I got new tires about 5 years ago. My old tires were the original BFG KO. They were in balance. But new tires are KO2, also balanced. I think the old ones were load range D while the new ones are Load Range E. Both were/are 285/75-16. I also put new OEM shocks on the front because the bottom bushings disintegrated around the same time as I put on the new tires.

 

[Yeti80]

I had this issue at roughly 50mph. I since then purchased a part time kit and had the front drive shaft rebalanced and yokes replaced and it drives smooth as it should. Though I don't use the front drive shaft for normal driving due to the part time kit, but by process of elimination, I can confirm the driveshaft was the issue.

 

[fussychicken]

Hi all, sorry for the radio silence. I only wanted to report once I had some good news, but sadly I haven’t had much good news to report.


Update on the Balanced Rear Shafts: Got them back from the driveline shop. I had given them two brand new OEM rear drive shafts. I asked them to “test” one and “balance” the other one. The one they tested they said was totally fine and in balance. And the one they balanced, he said they tried to get it as smooth as possible. They even heated up the metal to smooth out a spot? (I’ve never heard of this before) They said they were able to balance it at the tight end of their tolerance. Sad news is that it didn’t fix much. Vibration still there. I tried installing it in both directions, and while it was slightly better with the slip yoke by the TC, the vibration and drone was still there. Primarily 55-65ph.


Installing a new front driveshaft: I saw on this thread a few people saying they had success when changing out both driveshafts, so I went ahead and purchased a new OEM one during the last 25% off sale. Installed it just last week, and once again, sadly no improvement.


Trying to understand “system” vibration: Before installing the new front driveshaft, I took out the old one and took a drive with the center diff locked. Surprisingly the vibration changed. The overall level was much lower, and the vibration peak at 65mph had a higher frequency characteristic. This of course gave me some hope that the new FDS would fix the issue. (although it did not)

As posted in this thread, a few months ago I had done the same thing with the rear shaft out and center diff locked. That made the vibration go nearly completely away which of course was the reason I was so focused on the rear drive shaft as the culprit.

Anyway, all this makes me feel a little more skeptical about the “test to identify the bad driveshaft” by taking it out and driving with the CD locked. I’m glad if this has worked for others, but for me at least all it seems to be doing is confusing the issue.


Whats Next: Man I have no idea. So depressed about this all. I’m now nervous there is something wrong with one of the diffs and/or the transfer case. Was going to do a little research about others who have had transfer cases go bad and see how common this is.

 

[LJE]

Hi all, sorry for the radio silence. I only wanted to report once I had some good news, but sadly I haven’t had much good news to report.


Update on the Balanced Rear Shafts: Got them back from the driveline shop. I had given them two brand new OEM rear drive shafts. I asked them to “test” one and “balance” the other one. The one they tested they said was totally fine and in balance. And the one they balanced, he said they tried to get it as smooth as possible. They even heated up the metal to smooth out a spot? (I’ve never heard of this before) They said they were able to balance it at the tight end of their tolerance. Sad news is that it didn’t fix much. Vibration still there. I tried installing it in both directions, and while it was slightly better with the slip yoke by the TC, the vibration and drone was still there. Primarily 55-65ph.


Installing a new front driveshaft: I saw on this thread a few people saying they had success when changing out both driveshafts, so I went ahead and purchased a new OEM one during the last 25% off sale. Installed it just last week, and once again, sadly no improvement.


Trying to understand “system” vibration: Before installing the new front driveshaft, I took out the old one and took a drive with the center diff locked. Surprisingly the vibration changed. The overall level was much lower, and the vibration peak at 65mph had a higher frequency characteristic. This of course gave me some hope that the new FDS would fix the issue. (although it did not)

As posted in this thread, a few months ago I had done the same thing with the rear shaft out and center diff locked. That made the vibration go nearly completely away which of course was the reason I was so focused on the rear drive shaft as the culprit.

Anyway, all this makes me feel a little more skeptical about the “test to identify the bad driveshaft” by taking it out and driving with the CD locked. I’m glad if this has worked for others, but for me at least all it seems to be doing is confusing the issue.


Whats Next: Man I have no idea. So depressed about this all. I’m now nervous there is something wrong with one of the diffs and/or the transfer case. Was going to do a little research about others who have had transfer cases go bad and see how common this is.

Bummer - that nearly exactly mimics my situation. Pulling driveshafts helps, but doesn't eliminate the issue. My diffs are 'new', and I swapped my transfer case even.

Have you applied any sound deadening (like dynamat or similar) to your interior body panels per chance?
Somehow in the back of my mind I wonder if when I did this on my LX if I somehow managed to drop some of the body panel resonance frequencies into a problematic range. That's a weird stretch, but here we are...

 

[fussychicken]

Bummer - that nearly exactly mimics my situation. Pulling driveshafts helps, but doesn't eliminate the issue. My diffs are 'new', and I swapped my transfer case even.

Have you applied any sound deadening (like dynamat or similar) to your interior body panels per chance?
Somehow in the back of my mind I wonder if when I did this on my LX if I somehow managed to drop some of the body panel resonance frequencies into a problematic range. That's a weird stretch, but here we are...

Yeah, I just read your post and saw you tried a transfer case swap!! And yes, I remember you had done front and rear diff work as well. Wild to hear that didn't fix it! This puts me even more at a loss for words. And you have done so much more work than I have.

And no, I haven't done any sound deadening work. I'm fully on the boring, bone stock, OCD baseline path right now.

I will say that all this work has at least made it somewhat better. The other big change is that it is much more throttle dependent now. Before all this work, it was the same whether you were on the throttle or not. But now, it is more noticeable when on throttle. But at the end of the day it is still super annoying and drives me crazy.

And back to the system vibration topic, part of the reason I am going so crazy is when I do take out the rear drive shaft and drive around with the CD locked, it is still so smooth. So I know I'm not crazy. I know it can be better!

 

[fussychicken]

@LJE I saw you wanted to make a master list of all the things you have tried. I don’t think this will help as I believe you have done more than me, but here is my latest list of “parts canon” items I have done:


Things I've changed (all OEM parts):

• Front CVs
• Front Flanges
• All new Front UCAs
• All new Front LCAs
• New No2 LCA Bushing
• All three front diff housing bushings
• New Motor Mounts
• New Trans Mount
• New Mobil 1 Syn 75-90 in front, center, and rear diff
• Repacked front bearings
• Repacked front needle carrier bearings
• Front End Alignment to OEM spec
• Rear Driveshaft
• Locally Rebalanced Rear Driveshaft
• All new rear suspension arms including panhard
• Yes, I still have my frame weight
• Front driveshaft (front transfer to front diff)
• Change direction and put slip yoke up by transfer case
• Transfer case rear bearing

Things I haven’t done:

• Rear Axle Bearings
• Rear Axle Driveshafts
• All new Transfer Case
• All new Rear Diff
• All new Front Diff
• Body Mounts
• AHC Shock Mounts
• Anchor Arm Bracket Bushing
• 7 Year old Michelin LTX (but still look good)
• All new front wheel bearings (as listed above, I repacked last time)
• All new Transmission (currently has a toyota reman installed 100k miles ago)

 

[LJE]

@LJE I saw you wanted to make a master list of all the things you have tried. I don’t think this will help as I believe you have done more than me, but here is my latest list of “parts canon” items I have done:


Things I've changed (all OEM parts):

• Front CVs
• Front Flanges
• All new Front UCAs
• All new Front LCAs
• New No2 LCA Bushing
• All three front diff housing bushings
• New Motor Mounts
• New Trans Mount
• New Mobil 1 Syn 75-90 in front, center, and rear diff
• Repacked front bearings
• Repacked front needle carrier bearings
• Front End Alignment to OEM spec
• Rear Driveshaft
• Locally Rebalanced Rear Driveshaft
• All new rear suspension arms including panhard
• Yes, I still have my frame weight
• Front driveshaft (front transfer to front diff)
• Change direction and put slip yoke up by transfer case
• Transfer case rear bearing

Things I haven’t done:

• Rear Axle Bearings
• Rear Axle Driveshafts
• All new Transfer Case
• All new Rear Diff
• All new Front Diff
• Body Mounts
• AHC Shock Mounts
• Anchor Arm Bracket Bushing
• 7 Year old Michelin LTX (but still look good)
• All new front wheel bearings (as listed above, I repacked last time)
• All new Transmission (currently has a toyota reman installed 100k miles ago)

Excellent list! I need to sit down and do mine.

One thing I've seemed to notice - it definitely seems better when the truck is loaded with stuff in the cabin. Both on my way to Cruisers on the Rocks in OCT and GSMTR in JUN it was better, but I had a bunch of stuff taking up space and adding mass to the cab each time.

It also seems like it is somewhat throttle related in my case as well - the pitch still seems speed related (or at least spacing between pulses), but the intensity seems to be driven by if I'm on the throttle or not. Engine RPM still doesn't make a difference though.

I believe you're totally correct in saying that it's a system-level problem at this point...

One thought - I realized the other day that when I open the sun roof shade that I can hear air infiltrating - but, again, only when I'm on the throttle. That makes zero sense to me, and I haven't had time to go investigate why, but just a thought. You can't hear it in my truck without opening the sunroof shade. I discovered this noise because if I open the sun roof, the ear pain goes away - I'm assuming because the pressure in the cabin has somewhere to go right by my head. Oddly enough, opening all the other windows doesn't help nearly as much as you think it should.

 

[uHu]

I haven't read much about trying a different, complete set of wheels and tires in the latter part of this thread, preferably a street type tire without a course pattern. The idea is that the drone is a product of interference between the frequency produced by the individual tires. Much like the drone you get from a two engine propeller aircraft.

 

[Octous]

Interesting thead. Appreciate you documenting this journey.

Have you considered u joints for rear driveshafts? Also amount of lift you are running?

 

[fussychicken]

Paging @2001LC here if you don't mind commenting on this topic. As I mentioned in the AT fluid swap thread, this issue has been driving me crazy (along with @LJE who seems to have a similar, but maybe not exactly same issue. And also @Usterzai who has also shot the parts cannon at his.)

I've got lots of posts above, but I think the TL;DR is this:

• Vehicle is a bone stock 2001 LX w/ 255k miles. Been baselining her like crazy over the last 2 years.
• I've shot a huge parts cannon at the problem, and while it has gotten better, I still have a vibration when I'm on the highway only under acceleration between 55-65mph. Doesn't matter if I'm in 3rd or 4th gear. It is a deep booming noise with enough vibration to noticeably shake the rear view mirror. It is not a cyclical womp womp womp noise.
• For many (but not all) people in this thread, a new rear driveshaft seem to fix this issue, but that hasn't been the case with me. I've tried TWO different all new OEM shafts that have improved the problem but not fixed it.
• What drives me crazy is when I take out the rear shaft and drive with the CDL locked, it is smooth as can be on the highway. Which leads me to believe it is something driveline related.

Curious if you have any ideas here?

 

[2001LC]

Paging @2001LC here if you don't mind commenting on this topic. As I mentioned in the AT fluid swap thread, this issue has been driving me crazy (along with @LJE who seems to have a similar, but maybe not exactly same issue. And also @Usterzai who has also shot the parts cannon at his.)

I've got lots of posts above, but I think the TL;DR is this:

• Vehicle is a bone stock 2001 LX w/ 255k miles. Been baselining her like crazy over the last 2 years.
• I've shot a huge parts cannon at the problem, and while it has gotten better, I still have a vibration when I'm on the highway only under acceleration between 55-65mph. Doesn't matter if I'm in 3rd or 4th gear. It is a deep booming noise with enough vibration to noticeably shake the rear view mirror. It is not a cyclical womp womp womp noise.
• For many (but not all) people in this thread, a new rear driveshaft seem to fix this issue, but that hasn't been the case with me. I've tried TWO different all new OEM shafts that have improved the problem but not fixed it.
• What drives me crazy is when I take out the rear shaft and drive with the CDL locked, it is smooth as can be on the highway. Which leads me to believe it is something driveline related.

Curious if you have any ideas here?

Shot in the dark:

The 98-02 has a Y tube, both breathers for the transfer case and AT connect to. A single, 24" lengths, hose runs from Y, up to breather. I'm finding these hose full of fluid. Drain the hose. Set AT fluid level, while at ~158F, idling on level ground. Set transfer case level, flushing with fresh Mobil 1 75-90 gear lube. Again on level ground. Do the same for rear diff.

If vib still there afterward. Get an automotive listening device. Try to pinpoint.