Help diagnose intermittent growl/vibration/shudder?

[photon53]

I have a 2012 I bought with 135K miles, and no maintenance history. It has this strange grabbing growl/shudder vibration that happens very intermittently and only for a few seconds at a time. I am not aware of any dash lights coming on, and the only OBDII code is that it is unhappy about the signal shape it is getting from the front ABS sensors, but the ABS system is supposed to be OK. This shudder came with the van, and is still happening despite some major part replacements.

 

Between 40-60 mph, normal level straight dry asphalt roads, van empty or loaded with ~1000 lbs, it suddenly feels and sounds kind of like one wheel is running over a growler strip. There is a bit of vibration I can feel in the steering wheel, and the van shakes a little, and slows down a very little bit. But this only lasts for 2-4 seconds and stops. It can happen twice in 20 miles, then not for the next 100 miles on the same drive, or not happen at all for 300+ miles.

 

In zeroing out the maintenance schedule and eliminating all the existing obvious problems, I replaced CV axles, wheel bearings, tie rod ends, control arms, ball joints, outer tie rods, bar links, every moving part in the front suspension and drive train except the struts which seem fine. Motorcraft, Moog, new CSG CV axles; "good" parts. (Note: the Motorcraft wheel bearings were NSKs). I replaced all the rear brake parts and find the rear wheel bearings to spin smoothly with no obvious problem.  Flushed in new car juice in all possible systems. This shuddering has not changed at all.

 

I have new Timken rear hubs in my parts box, but I am not certain this is the problem at this point. It does feel like a brinelled wheel bearing might feel, but it happens so seldom...

 

Could this be a brake or two chattered by the ABS, or some weird transmission gremlin? Or what?

 

Profuse thanks to the community for providing such useful information on these vans!

[Beta Don]

You've certainly replaced all the expensive parts.  Since the only code you have involves the brakes, why not try a new pair of rotors up front?  Cheap and quick enough to do with some rotors from Rock Auto

 

Don

[G B L]

If  you disconnect one of the Abs sensor plugs It wills set a code , but it will disable the Traction control and eliminate the ABS function  if the shudder goes away then you know where the problem is .  If one of the brake hoses is restricted it could make a caliper hold pressure on a disc. The tell tale on that is one of the front wheel  would be much hotter than the other.

 

[PhotoAl]

I'm thinking ABS issue.  My wife's car one time had a problem that we think was the stability control kicking in at the wrong time.  One of her front tires was very low and the car tried to make a left turn!   Vey scary for her.  We had it towed home where I checked tire pressures and cleaned all of the ABS sensors.  Been three or four yeas and the problem has never reoccured.  I would check the ABS sensors to make sure they are clean and free from dirt and metal garbage.  Check the connections to make sure they are secure.  Im tempted to say use some electrical dielectric compound but not sure about those connections as they are very important to ABS, traction control and stability control.  I would not count out wheel bearings either as it may be a slight difference in road slope or surface of something that causes the vibration.  Good idea to check brake rotors although Id use a temperature gun as they can be very warm after driving.  

[photon53]

GBL, which ABS sensor plugs are you talking about disconnecting?

 

I recently had all four of the wheel speed sensors out while I did the various parts replacements and cleaned them up.

 

I also had the brakes at the wheels apart and flushed the brake system with new fluid and did not see any problems with plugged lines or hoses. Today I raised all the wheels up just to verify that the brakes aren't dragging anywhere, and none of the wheel bearings is loose.

 

Correcting for speedometer error, I have been getting 24+ mph combined town/country gas mileage and also running on I5 at 70 mph with a heavy load, so brakes may not be dragging much. Or should I be doing better on the gas mileage? I have an Adrian Steel commercial rack on the roof and the van needs a wax job.

 

I will carry my infrared thermometer with me and check the rotor temps.

 

Thank you all for your ideas.

[G B L]

If you want to disable the ABS any wheel sensor  will do, once the computer senses that one of the wheels is not reporting in it will disable the system.  If the shudder goes away then there is a problem in the ABS.

If you have a scan tool with ABS you can read the wheel speed sensors and get that information.

[photon53]

Time for an update on this shudder problem: Thanks to GBL for the ABS sensor disconnect suggestion. I disconnected the right rear ABS sensor wire and the problem seemed to have stopped. Keep in mind I drive this van intermittently, about 6K miles the first year, and most of that is in town. I loaded the van up to 4600 lbs on the scale and drove 535 freeway miles in one day and had no noticeable problem. Driving back from the same place at ~5000 lbs, Valiant sheetmetal on the roof rack and a ~20 mph headwind in two days the shudder returned and happened like 20 times a day, often enough I had more opportunity to observe. It shuddered only as the tranny is shifting up from 3rd to 4th on fairly level road.

 

A mechanic friend referred me to Geezer Garage in Coburg, Oregon, where Gary put his mobile code reader on and watched as we drove around. He identified the problem as torque converter shudder as it goes into lockup mode. It is going into lockup a little earlier than it is supposed to, so it feels like the 3rd-4th upshift is when it happens. He didn't think it was much of a concern as far as getting stranded or imminent transmission hira-kiri.

 

Gary recommended LubeGard Shudder Fix, a 5 oz. $9 tube of transmission additive. It seems to be working, although only more miles will tell. I have also ordered some LubeGard Platinum ATF Additive to hopefully extend the life of the transmission.

 

Thank you for your good ideas!

[Fifty150]

 

4 hours ago, photon53 said:

 It shuddered only as the tranny is shifting up from 3rd to 4th on fairly level road.

 

A mechanic friend referred me to Geezer Garage in Coburg, Oregon, where Gary put his mobile code reader on and watched as we drove around. He identified the problem as torque converter shudder as it goes into lockup mode. It is going into lockup a little earlier than it is supposed to, so it feels like the 3rd-4th upshift is when it happens. He didn't think it was much of a concern as far as getting stranded or imminent transmission hira-kiri.

 

That sounds like a common problem on 4 speed transmissions going into lockup or overdrive.    Big issue with the 4RXXX series of Ford transmissions.

4 hours ago, photon53 said:

Gary recommended LubeGard Shudder Fix, a 5 oz. $9 tube of transmission additive. It seems to be working, although only more miles will tell. I have also ordered some LubeGard Platinum ATF Additive to hopefully extend the life of the transmission.

 

Thank you for your good ideas!

Gary should have recommended a complete fluid exchange.  First, get out all of the contaminated fluid.  The transmission may not shudder once you are operating with clean fluid.  Next would be to drop the transmission.  Your choice would be to either install a remanufactured transmission (expensive).  Or allow Gary to take apart the transmission, diagnose the problem, correctly rebuild the transmission replacing all wear items, and reinstall the transmission.  Even more expensive, depending on what Gary charges for labor & parts.

 

Do you really trust Gary, who thinks that $5 worth of friction modifier actually fixes worn internal components and contaminated fluid, to troubleshoot and rebuild your transmission?  Let's say Gary gets on the job right away.  He spends a day taking your transmission down, another day of two opening it up & and repairing to the best of his ability with a tube of LubeGard, and hopefully it's only 1 week's worth of Gary's labor + parts.  Now you will have to trust that Gary has full knowledge of your transmission model, and has all the skill, training, & experience to rebuild it as good as new.  

 

Or pay a transmission shop for a remanufactured transmission, built at a factory, which they can install in 1 day?  

 

Gary may be a good mechanic.  But he is probably not a transmission builder.  Same way the lube technician is not an engine builder.  LubeGard & Lucas Oil Transmission Fix is strictly amateur, do-it-yourself in the driveway, & cross your fingers.  Your transmission is shuddering because the contaminants in your fluid are clogging passages, and interfering with proper engagement.  In the process, moving parts which depend on your transmission fluid to be clean, are most likely damaged and need to be replaced.  A little extra thick goop may provide temporary relief.  But there is not mechanical solution in a $5 tube.  From the best of my recollection, You are always suppose to replace contaminated fluid with fresh fluid, then add the lubrication additive.  Adding friction modifiers to contaminated fluid is just not a good idea.