Shudder/Vibration Around 40-45 MPH, then 60 MPH +

[97Ranger3.0]

First of all; I'm not sure where best to post this, so if it needs to be moved elsewhere I'm sorry about that!

So, I've got a 1997 Ranger 4x4 3.0 5 speed regular cab 7' bed. I've had this issue since I got the truck 2 years ago and have still not figured out the issue. Basically, there is this annoying shudder/vibration that is most noticeable between 40-45 MPH, any speed slower or faster it is not very noticeable except above 60 MPH where it starts to almost qualify as death wobble. The best way I can explain the shudder at 40-45 is that I feel it most under the seat, it's not a steering wheel shimmy like unbalanced tires. It feels like there is something wrong in the driveline, as it almost feels like the truck is bucking back and forth slightly. It doesn't matter if I'm in 3rd, 4th or 5th or even 2nd; any gear at that speed causes this issue. The vibration gets just slightly worse when braking, but just barely. When the vibration comes back at 60+ it feels more like the original shudder plus something similar to a tire balancing issue so it gets quite wobbly. Also one thing I would like to note is that the shifter will visibly wobble back and forth at those higher speeds. With all that being said, here is everything I've done to the truck worth mentioning. Some of it wasn't necessarily in an attempt to fix the vibration but is worth mentioning to be able to be ruled out (hopefully).

- I've run several different wheel/tire combinations, both unbalanced and balanced at different times, not much difference. I only had one set of studded snow tires that made the problem worse. They made it so much worse that it was unbearable to drive if I had to cruise around 40-45.
- I've checked the pinion angle and currently have it set 2 degrees down compared to the transfer case flange; I will experiment with pinion shims soon and see if it improves with more angle, say 3 degrees or so.
- It has all new u-joints and at this point I've done every single bushing in the suspension, including new motor mounts and a polyurethane transmission mount.
- I don't feel any unusual play in any of the front end.
- I recently had the rear driveshaft worked on because I suspected it was out of balance and this was causing the problem. Upon inspection, the shop found that the slip & spline had too much play, so they made me a new one and a stub shaft for the transfer case end of the shaft and balanced the whole unit. This helped a little, but the problem is definitely still there.
- I'm running rear disc brakes because I swapped to an Explorer rear end, so I don't believe out of round drum brakes are causing the issue which I have heard of in some cases.
- There is absolutely zero play in the transfer case output shaft as far as I can tell from grabbing the flange and trying to move it. However, the transmission is a bit noisy in 4th and less so in 5th, not so much in any other gear.

That's about all that I can think of right now that might contribute. The only thing I haven't done yet is try to get the rotors turned. I don't suspect that warped rotors could cause this vibration because from what I've read that should only cause vibrations during braking. But, when I got the truck it had brand new front brakes so I've never touched them; so it is one thing that is a slight possibility that I haven't done. At this point, I'm not sure what else could really be left causing this issue so I plan on taking all 4 rotors to get turned today just to see if it changes anything so I can rule it out as well (or maybe I'll get lucky and it'll fix the problem).

Otherwise, should I take my driveshaft back to the shop and have them completely rebuild it? The rest of the driveshaft has what I'd consider minor surface rust on it and they didn't seem to come across any problems with it other than the slip & spline when they balanced it. Also, I was running a crusty junkyard driveshaft in my truck while they were working on my driveshaft and it didn't seem to change the shudder issue either.

I enjoy driving this truck, and have put a lot of work into it fixing and improving it over the years but this one issue is very frustrating. I tend to avoid highway driving because of this issue, but I would like to get this issue sorted so I don't have to do that any more because that is honestly just annoying and wastes time. Has anyone experienced anything like this? Is there anything I'm overlooking? Any input is appreciated.

 

[fastpakr]

A quick thought - have you tried driving it in 4wd with the rear shaft removed?

 

[91stranger]

I had a similar issue on my old ranger and it was from a bad carrier bearing for the drive shaft. I don't know if you have a 2 piece drive shaft or not but I would check that bearing if you have one. Some causing a severe shaking should be pretty easy to find.

 

[97Ranger3.0]

A quick thought - have you tried driving it in 4wd with the rear shaft removed?

I have thought about trying this, but forgot to actually try it. Thank you for the reminder! I will try this and report back soon.

I had a similar issue on my old ranger and it was from a bad carrier bearing for the drive shaft. I don't know if you have a 2 piece drive shaft or not but I would check that bearing if you have one. Some causing a severe shaking should be pretty easy to find.

Yeah I have a one-piece drive shaft so it's not a carrier bearing issue. Thank you though!

 

[97Ranger3.0]

I got my rotors turned the other day and also took the pads all back out, cleaned the surfaces they slide on and re-applied anti sieze to those surfaces as well as re-greased the guide pins. My front pads were pretty stuck, and the guide pins were also not too great. But anyway, I'm happy to say that the problem seems to be fixed! I took the truck all the way up to 75 MPH and it was death wobble free. I'm guessing that the rotors were warped and that was the main cause, although I'd imagine having sticky guide pins and pads that weren't moving easily didn't help the situation.

There is still a little bit of a shake around 40-55 or so intermittently, but it also became far less dramatic after getting the rotors turned. I did notice while I had the wheels off that two of the tires have bulges in the sidewall, so that might also be contributing. I bit the bullet and bought new tires and will be getting them mounted soon because I don't want to have any tire explosions. I didn't want to get new tires because mine have a lot of life in the tread, but the front two tires have some minor weather cracking in the tread and the bulges in the sidewall are just not safe to run, so I feel this is the best option.

I will continue to update this thread as I notice improvements (or hopefully not worsening of the problem!) so that hopefully this can help someone else.

 

[4x4junkie]

I was reading this thinking that maybe a bent wheel rim and/or a bent rear axle shaft could be the issue until you mentioned those tires.
It's almost for certain those tires are the problem.

 

[97Ranger3.0]

I was reading this thinking that maybe a bent wheel rim and/or a bent rear axle shaft could be the issue until you mentioned those tires.
It's almost for certain those tires are the problem.

Yeah I suspect so too, it's just odd because I've had this issue through a few different sets of tires and wheels. So at first I didn't think so. But seeing a bulge in the sidewall of 2 different tires (if I remember correctly) I think that may at least be partially to blame.

I was also very surprised at how much of a difference having the rotors turned made though, as I always thought that warped rotors only caused vibrations when braking. But anyway, I will be getting new tires soon due to these being unsafe so I will be able to say for sure if the tires were contributing

 

[19Walt93]

Most tires have a small bulge in the sidewall where the radial plies are bonded together that will look a lot more pronounced depending on how close to the contact patch the joint lands when you park.

 

[lvwill]

Do you have a double cardan joint at the transfer case end of the rear drive shaft?
If so any play at all in that joint will be basically a harmonic vibration in the truck. Also the the pinion should be pointed directly at the transfer case out put. Ujoints do really strange things when not in the proper phase.

 

[97Ranger3.0]

So I got my new tires mounted & balanced, I feel better knowing they are less likely to blow out on me lol. But I still have that shake at around 40-50 MPH, so it wasn't a tire issue. The best way I can describe this vibration is that it almost feels like the truck is lightly bucking back and forth at a fast rate. It's not steering wheel shake at all, it feels like a back and forth vibration front to back, not side to side like a tire balancing issue often feels like. This is why I originally suspected that there was a problem with my driveshaft, because that's what I'd imagine an out-of-balance driveshaft would feel like. It is super irritating because it is very noticeable and you can feel it in the entire truck. I did at least cure the higher speed wobble with the rotors getting turned, which seemed unlikely to me, but either way I'm glad that part of the problem is solved.

My next suspect is the engine mounts. I did replace them early on but I did use some no-name ebay brand so that could be my mistake. I have read about and seen videos of bad motor mounts causing a similar issue. It does seem like when this shake starts if I let off the gas and push the clutch in that it improves. It is hard to tell for sure because the speed drops fast but it does seem to consistently get better, which I could attribute to engine mounts in my mind. But I don't like just throwing parts at something, and I already spent that money getting work to the driveshaft done with minimal improvement; so I don't want to go spend the money on new mounts and spend the time installing them without knowing for sure.

So here are my thoughts, I have a few tests I would like to run soon when I have the chance. The first one is like fastpakr suggested, removing the rear driveshaft, locking the hubs, putting it in 4wd and driving it. If the problem goes away, I'd have to suspect there is still an underlying issue with the driveshaft, the pinion angle is still severely off or something along those lines. If the problem is still there, then it's something else in the drivetrain.
-I have a good polyurethane trans mount, so I have faith that is not an issue.
-The driveshaft has no play and was balanced recently and they had no problems doing so aside from replacing the slip joint because there was too much play.
-I don't think I have a bent axle, I would've noticed while I was replacing the clutch packs in the limited slip rear end I put in, plus this issue was present with my stock rear axle too.
-I have newer wheel bearings on all 4 corners.
-I believe that I have literally done every suspension bushing in this truck - axle pivots, radius arms, rear spring bushings, rear shackle bushings...
-Several different sets of wheels & tires, no real change.
-No play at the transfer case output.

That doesn't really leave too much else aside from motor mounts in my mind. Unless like I said there is an issue with the driveshaft or pinion angle still and it's just been missed. My other test is that I'd like to try to simulate this problem with the truck off the ground to see if I can see anything weird happening like the engine wobbling excessively to hopefully decide if the mounts are problematic or not.

Most tires have a small bulge in the sidewall where the radial plies are bonded together that will look a lot more pronounced depending on how close to the contact patch the joint lands when you park.

Well, I only saw the bulge on two of the tires if I remember correctly, and I wouldn't consider them small. They had me worried for sure. Maybe I'm wrong and they were normal, but they looked bad to me and I've never noticed such a distinct bulge in the sidewall of any other tire before. I wish I had gotten a picture before I had them dismounted.

Do you have a double cardan joint at the transfer case end of the rear drive shaft?
If so any play at all in that joint will be basically a harmonic vibration in the truck. Also the the pinion should be pointed directly at the transfer case out put. Ujoints do really strange things when not in the proper phase.

No I don't. Just a 1-piece driveshaft with a u-joint on each end and a slip joint towards the transfer case end of the shaft. My brother's Ranger has a double cardan rear driveshaft though and his truck has always been very smooth, especially compared to mine.

 

[19Walt93]

Have you tried indexing the driveshaft? If you have a dial indicator you can measure the runout at the front, rear, and center of the shaft, if the runout is highest in the center the shaft is bent, if it increases as you move from one end to the other indexing should help. If you don't have a dial indicator you can still try it. Mark the driveshaft first so you know where you started. Unbolt the companion flange, rotate the driveshaft 1/2 turn and bolt it back up and test drive. If the vibration changed, unbolt it again and turn it 1/4 turn this time then drive it again. Next repeat the procedure going another 1/2 turn and decide which position was best. The pinion flange has 8 holes so you can try those as well. Ford considers .035" acceptable driveshaft runout, I like a little less. If you don't want to do multiple test drives you can probably get a cheap dial indicator for $20. You didn't mention if it's worse under acceleration or decel, if throttle pressure changes it driveline angles should be checked, ideally the pinion angle is equal and opposite the angle at the transmission.

 

[91stranger]

U mentioned the guide pins earlier saying they weren't the greatest. Have you lubed these or replaced them yet? My truck did a death wobble shake and it was just the guide pins needing lubed. That was about a few thousand miles ago with no issues since lubing. I don't think that is your issue but it wouldn't hurt to make sure things were lubed. Have you checked the rear brakes? leaf springs and shackles? If you feel it coming from the rear then inspect the complete rear. Could be something as small and simple that you have over looked. I know people can easily over complicate stuff and cause more headache than help. Have you pulled the diff cover off? What does your truck do if you push on the bed sides back and forth and rock the truck really good? You shouldn't hear any clunking but if you do track down the noise. Only other suggestion would be to put it on 4 jack stands and "drive" the truck to see if you or a friend can see something. Unless you want to throw money at it these are free and simple tests.

 

[4x4junkie]

Can we get a better description of the vibration?

It is like a fast-shaking?
Or is it more like a low-frequency hum or buzz type vibration?

This might help us narrow it down some, since tires/wheels create a distinctly different frequency of vibration than driveshafts/u-joints do.



FWIW, I've noticed the discontinuities on tire sidewalls where the cords come together myself... They generally dimple inward, not bulge outward. An outward bulge would be much more cause for concern.

 

[97Ranger3.0]

Have you tried indexing the driveshaft? If you have a dial indicator you can measure the runout at the front, rear, and center of the shaft, if the runout is highest in the center the shaft is bent, if it increases as you move from one end to the other indexing should help. If you don't have a dial indicator you can still try it. Mark the driveshaft first so you know where you started. Unbolt the companion flange, rotate the driveshaft 1/2 turn and bolt it back up and test drive. If the vibration changed, unbolt it again and turn it 1/4 turn this time then drive it again. Next repeat the procedure going another 1/2 turn and decide which position was best. The pinion flange has 8 holes so you can try those as well. Ford considers .035" acceptable driveshaft runout, I like a little less. If you don't want to do multiple test drives you can probably get a cheap dial indicator for $20. You didn't mention if it's worse under acceleration or decel, if throttle pressure changes it driveline angles should be checked, ideally the pinion angle is equal and opposite the angle at the transmission.

I don't have a dial indicator but I will look into getting one. With the tests, are you saying to unbolt the driveshaft from one end, rotate it and bolt it back into a different set of holes on the flange to see if the vibration changes? And also I've tried a few different pinion angles at this point with only slightly different results. I've had the angles perfectly equal and opposite, meaning if my t case flange was 3 degrees down my pinion flange pointed 3 degrees up. That made the shudder/vibration slightly worse. Having the pinion pointed 1 degree down compared to the t-case, the shudder was slightly less dramatic. I've currently got the pinion around 2-2.5 degrees down and it feels the same as it did with 1 degree down.

It's very hard to explain this shudder issue, but I think I'll start by saying that calling it a shudder is more accurate than a vibration. As I mentioned in the previous post, it almost feels like the truck is bucking back and forth at a fast pace around those speeds (40-50MPH). It sort of feels like you're driving over a bunch of small steady bumps as the truck almost feels like it starts to bounce. As I've been driving the past few days I've been doing some tests to see if I can make the shudder change, and I've noticed that if I let off the gas and push the clutch in or toss it in neutral that the problem seems to go away or at least become a lot less noticeable. The shudder is definitely worse under acceleration, it also seems to less noticeable under deceleration if I'm still in gear decelerating, but I'd say the problem is least noticeable if I push the clutch in or shift into neutral. Hopefully this helps, it's hard to explain, I wish I could just take you guys for a drive and show you lol.

U mentioned the guide pins earlier saying they weren't the greatest. Have you lubed these or replaced them yet? My truck did a death wobble shake and it was just the guide pins needing lubed. That was about a few thousand miles ago with no issues since lubing. I don't think that is your issue but it wouldn't hurt to make sure things were lubed. Have you checked the rear brakes? leaf springs and shackles? If you feel it coming from the rear then inspect the complete rear. Could be something as small and simple that you have over looked. I know people can easily over complicate stuff and cause more headache than help. Have you pulled the diff cover off? What does your truck do if you push on the bed sides back and forth and rock the truck really good? You shouldn't hear any clunking but if you do track down the noise. Only other suggestion would be to put it on 4 jack stands and "drive" the truck to see if you or a friend can see something. Unless you want to throw money at it these are free and simple tests.

Sorry, this might have not been clear in my post about getting the rotors turned. But I did remove the guide pins and re-greased them so they moved nice and freely before I put the brakes back together. And I cleaned up the contact points where the pads slide in the caliper and applied a little anti-seize. So it should all be moving freely now, and as I said this helped the higher speed wobble which was a different vibration than the 40-50mph shudder that I'm still experiencing. The wobble I had at 65+ felt like the whole truck was wiggling or wobbling side to side at those speeds, and the brake work fixed that - which is similar to what you experienced. But the lower speed shudder is still there. And yes I did all 4 brakes (I have 4 disc brakes so I got all 4 turned and lubed all guide pins and all that).

As I've said in previous posts, I've also done leaf spring and shackle bushings. Also I haven't mentioned this yet, but I had recently swapped to chevy leaf springs. But with both my original factory springs & shackles with shot bushings and these chevy leaf springs with new bushings & shackle bushings the problem has always been present. As for pulling the diff cover off - again, I've mentioned that both with the original 7.5 axle and with the explorer axle I've swapped in the problem has always been present. I've popped the covers off of both diffs and both looked great. I also had the explorer axle apart before I put it in my truck to replace the wheel seals and bearings as well as to replace the limited slip clutches, so I feel like if there was a problem with that rear axle I would've noticed while I had it apart. And again, this shudder was there with the original axle too and the problem didn't change at all when I swapped axles. And yes, when I have a chance I plan on doing that exact same test you mentioned to see if that will help me pinpoint the issue. I don't like to throw money around buying parts unless I know they are a problem which is why I'm asking for advice because I'm kind of lost with this issue. Everything I've done so far that I've mentioned is stuff I've had to do for other reasons or stuff I wanted to do.

Can we get a better description of the vibration?

It is like a fast-shaking?
Or is it more like a low-frequency hum or buzz type vibration?

This might help us narrow it down some, since tires/wheels create a distinctly different frequency of vibration than driveshafts/u-joints do.



FWIW, I've noticed the discontinuities on tire sidewalls where the cords come together myself... They generally dimple inward, not bulge outward. An outward bulge would be much more cause for concern.

See the 2nd part of my response to 19Walt93, hopefully that helps. It is more of a fast shaking back and forth than a vibration. I don't hear any noise associated with the sensation and calling it a shudder seems like a better way to describe it. Also, I don't know if this helps at all; but if I've got something in the truck with me, let's say I've got a gallon jug of coolant or something sitting on the passenger floor. You can visually see the jug shake back and forth (front to back not side to side) at those speeds, and not at other speeds. Also as I'm driving I can even see the passenger seat shimmy back and forth at those speeds if someone's not in it.

Also I would agree regarding the tires. I've noticed small dimples inward on good tires like the ones I now have, but there were distinct outward bulges on two of my old tires. The bulges on those tires were much more noticeable than the small dimples on good tires if that makes sense. Which is why I got new tires because those had me concerned.

Also thank you all for your help so far. I'm determined to fix this and if so I hope that this thread will help someone else in the future with a similar problem.

 

[91stranger]

Yep, I would put it on 4 jack stands and get a friend to help you. That would be your cheapest option without throwing parts at it. Since it is shaking so much it should be obvious once you get it "driving" on jack stands. Does it feel more toward the rear, middle or front when it shakes? If it goes away when in neutral then you may have transmission issues.... I had a 97 explorer with the all time awd and it would do something similar. Really heavy bucking back and forth, slipping in and out of gear. Only did it when the engine warmed up. Never did it cold. Never figured it out either. I ended up junking it due to the mile long list of issues with it and no money to put towards it. I was told it was a bad shift solenoid but who knows. Wish I would have kept that explorer as it had the 5.0 that everyone wants in their ranger.