At wits' end: yes another highway vibration thread!

[AzCosta]

Well all this hits close to home. I went through hell and back blaming the tire shop, ended up with all kinds of new front suspension parts, new tires and new rims......and still have the 65-70ish vibration.

I'll have to follow this to see if you get any resolution.

My indication to check the driveline was at cruising 65 mph with a very slight acceleration the vibration was there. Then I immediately followed by a very slight lift off the gas and the vibration would go away. ("feathering" the pedal if you will). Pretty much told me I either have a transmission problem, driveline problem, or differential (or my seat wasn't bolted down very well) . Driveline was it.

 

[96LTDrus]

take the 4runner to the driveline shop and have them drive it.

let them see for themselves that its not balanced properly, or at the least there is a vibration there.

Yeah I think that's my next step. Also, that same old low frequency 'wobble' is as present as ever :/

I played around a bit with the air pressure in my rear shocks (Monroe adjustable units), going from 30 to 50psi raises the rear of the truck a good inch or so. In the past I thought I had observed that this had some effect on the low frequency wobble, but it didn't seem to make things any better at all tonight.

One thing I noticed on the driveshaft was that my alignment marks for the 2 flanges that I had made no longer lined up. If the front T-case to front Cardan joint was lined up, then the rear u joint flange to diff flange was off 180 degrees. My best guess is that the shop reinstalled the flange part of the yoke in a rotated fashion. Is this important? I mean it 'balanced out' supposedly (but as we see not at all).

 

[96LTDrus]

So I'm taking the driveshaft back to the shop tomorrow, the guy was kind of non-chalant and said "yeah sure no problem we'll take another look at it." Also the U joint they installed has the zerk wedged between two of the bearing caps, my grease gun literally cannot fit in that tight space. Hopefully they can install a different u joint style, maybe I'll have to buy a Spicer at Advance Auto or something.

One factor I've never considered is my front driveshaft. It looks pretty groaty, with a rusty slip joint surface. Now I understand that there is no torque being transferred to this shaft when in 2Hi, but I've read somewhere that it still rotates when driving due to the way ADD disconnects? Anybody want to drop some knowledge on me about that? Once the rear DS is balanced properly for a change if there are still the low frequency wobbles my next thing to check is going to be removing the front DS and driving around like that. For what it's worth I've never noticed anything strange when driving in 4Hi, up to 60mph. No weird vibrations, nothing.

 

[gamefreakgc]

So I'm taking the driveshaft back to the shop tomorrow, the guy was kind of non-chalant and said "yeah sure no problem we'll take another look at it." Also the U joint they installed has the zerk wedged between two of the bearing caps, my grease gun literally cannot fit in that tight space. Hopefully they can install a different u joint style, maybe I'll have to buy a Spicer at Advance Auto or something.

One factor I've never considered is my front driveshaft. It looks pretty groaty, with a rusty slip joint surface. Now I understand that there is no torque being transferred to this shaft when in 2Hi, but I've read somewhere that it still rotates when driving due to the way ADD disconnects? Anybody want to drop some knowledge on me about that? Once the rear DS is balanced properly for a change if there are still the low frequency wobbles my next thing to check is going to be removing the front DS and driving around like that. For what it's worth I've never noticed anything strange when driving in 4Hi, up to 60mph. No weird vibrations, nothing.

Yeah it still rotates but I don't think it would be enough to cause the whole vehicle to vibrate though. There's no load on the front drive shaft in 2WD so it shouldn't make much of a difference.

 

[JayRolla]

I had all these issues, fixed it by going to junk yard and pulling 100k mileage shaft. Will be sending old shaft out to be rebuilt with oem parts here soon. Most driveline shops use crappy cheap u joints that fail 10-20k miles.

 

[96LTDrus]

I had all these issues, fixed it by going to junk yard and pulling 100k mileage shaft. Will be sending old shaft out to be rebuilt with oem parts here soon. Most driveline shops use crappy cheap u joints that fail 10-20k miles.

Yeah I'm almost tempted to run and buy a DS out of one of the two wrecked 3rd gens in the pickapart here in Indy, I'm just mad that I let this shop mess with my factory balance with 'straightening' and whatnot. I still have no clue how it possibly could have gotten bent leading the easily life that it has. We'll see what a re-balancing turns up. I also calculated what rpm the shaft is spinning at when I'm at 70 mph so I want to confirm that they take it up to atleast 3300rpm on their machine and preferably up to something like 4500rpm (95mph) to really be certain.

 

[96LTDrus]

The driveshaft is back at the shop, I had asked the guy what rpm they balance to and he said 2800. That corresponds to 60mph on my 4Runner with my current tires and 4.30 rear end. My current driveshaft 'hum/buzz' vibration occurs from 60-70mph then from about 74+mph. 70mph is about 3320rpm with my setup. He claimed that that 2800 is their standard balancing speed and that they do the same for racing applications that see 10000rpm. Another driveshaft shop in town said the same thing, balancing at 2500rpm or so should catch anything that shows up even at much higher speeds on the highway. I also showed him how my grease gun can't access the zerk on the new joint they installed. He said his guys would 'check it out' and rebalance things. My confidence in these guys is very quickly waning. We'll see what they come up with today.

Local junkyard sells DS for $20 with core, I'm awfully tempted to scoop one up just in case.

 

[96LTDrus]

Could me missing a driveshaft lubrication last oil change be a source of vibration, some way, somehow?

Probably not, although maybe if you have a u joint that's a bit borderline worn out, having it really well lubricated could have masked that. In my case I could have sworn I sometimes would have long stretches of time when everything was fine, like when I first got the truck back from its initial look-over and tune up at my brother's place. Then over time things went back to the usual. Although it could be that I just became much more attuned to smaller vibrations as the big sources of issues got sorted out over time (worn shocks and bushings, etc).

 

[gamefreakgc]

The driveshaft is back at the shop, I had asked the guy what rpm they balance to and he said 2800. That corresponds to 60mph on my 4Runner with my current tires and 4.30 rear end. My current driveshaft 'hum/buzz' vibration occurs from 60-70mph then from about 74+mph. 70mph is about 3320rpm with my setup. He claimed that that 2800 is their standard balancing speed and that they do the same for racing applications that see 10000rpm. Another driveshaft shop in town said the same thing, balancing at 2500rpm or so should catch anything that shows up even at much higher speeds on the highway. I also showed him how my grease gun can't access the zerk on the new joint they installed. He said his guys would 'check it out' and rebalance things. My confidence in these guys is very quickly waning. We'll see what they come up with today.

Local junkyard sells DS for $20 with core, I'm awfully tempted to scoop one up just in case.

Dude for $20 why not try it? Worse case scenario you have a spare if you can fix the current one. I wish my local yards carried 3rd Gens... they are valuable around here so the auto dismantlers get them first and charge 3x the price.

 

[96LTDrus]

Dude for $20 why not try it? Worse case scenario you have a spare if you can fix the current one. I wish my local yards carried 3rd Gens... they are valuable around here so the auto dismantlers get them first and charge 3x the price.

Yeah that's what I'm thinking.

Picked up my DS from the shop at lunch, to amend the inaccessible zerk issue they screwed on this goofy looking extended zerk. It works and doesn't seem to interfere with the yokes, but looks ridiculous. The guys just didn't want to install a 'normal' Moog or Spicer style u joint, they just wanted to save time and money. They also rebalanced it, said they found a bit of runout by the double cardan, I now have a balancer weight tack welded on by the rear joint on the surface of the slip joint (near the limit of its travel) :mmph:. Again, doesn't affect driving in terms of the slip joint ever moving there, but it just looks sloppy. If it's finally balanced then I'll be happy to drive around with this frankenstein thing. If not then its off to the junkyard I go!

 

[96LTDrus]

Progress!! i.e. Zero sum game

The re-balance job on my original DS has as expected yielded no results what-so-ever. Hopefully I can get a refund for my now unbalanced shaft.

So I picked up a spare driveshaft at the junkyard off of a 2000 SR5 4WD, mileage unknown, shaft was completely OEM-unmessed around with (factory square balance weights). Front double cardan felt fine, rear u joint felt okay but has a small bit of looser movement near center in one of the axis. Plunked down my $23 and headed home. Greased 'er up and bolted it on.

Wow, how fantastic it is to drive down the highway without that constant buzzing drone of an unbalanced driveshaft. However, the worn u joint is definitely felt, applying a decent amount of gas to accelerate say from 65-75 in top gear yields the same old lower frequency wobble, I think my original shaft with the new u joint (and poor balance) no longer had this behavior.

So in sum, I'm back to where I started but a bit smarter. Will report back once I have a new u joint installed in my junkyard driveshaft....and no more goddamn balancing!

My conclusions (to be verified once I install a new u joint in my new junkyard shaft):

If your highway vibrations are a constant high frequency 'hum' or 'buzz,' your driveshaft needs balancing (or you have some gnarly tires :thumb3

If your highway vibrations are intermittent, felt in the seat of your pants, and happen particularly when load is applied, then it is probably a u joint, or you should look into unloading some grease from slip joints.

If the vibration is mostly felt from one particular corner of the car, or is felt in the steering wheel, and happens consistently at a particular speed/range (ex: always starts at 70 mph), then chances are you need the wheels balanced, PROPERLY.

Finally, worn suspension components and steering racks/bushings will make any of the above more pronounced and or/intermittent.