Shake or Vibration Issues

[hotrodz37]

Epiphany moment. Loose u bolts on axle, is the axle rotating in the cups. , therefore you working angle is out of spec because the diff u joint is or has rotated

 

Unfortunately not the case. I thought I had stumbled onto something as well but after torquing them down I still have the vibe.

 

 

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[14silverado4.3]

Possible they rotated before you torqued them down? Is your driveshaft angle correct?

[hotrodz37]

Possible they rotated before you torqued them down? Is your driveshaft angle correct?

It is certainly possible and I have not checked the shaft angle.

 

 

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[14silverado4.3]

I drove 15000 miles before I tightened them down, tightened them because of vibration. I will check angle

[Jesse Davidson]

its pretty sketchy that they were only torqued to half they spec

[14silverado4.3]

Coming from manufacturing, I wonder if they had to facilitate a repair and missed the final torque sequence. This would explain why it does not show up immediately but over time. Hit or miss, comes and goes, the axle may be turning in the cradle, continuously changing the working angle of the driveshaft. Is it possible?

[Jesse Davidson]

regardless, to happen on enough vehicles to warrant a recall? thats sketchy

[abominable z71]

as promised here is a link for the rough idle video. I have compared my truck with Bill's 6.2 and his truck has virtually no movement at idle, unlike mine. Bill can attest to this, this video doesn't show how bad my rough idle can actually be, today was actually relatively good comparatively speaking

 

 

Maybe you should try a bottle of smart water instead of aquafina. J/k gotta keep a sense of humor with these trucks though otherwise they'll drive you nuts. I'll do the water bottle test on my 5.3 this weekend and take a quick video. What rpm does the 4.3 idle at? My 5.3 idles at just a tick over 450 RPM.

[abominable z71]

Coming from manufacturing, I wonder if they had to facilitate a repair and missed the final torque sequence. This would explain why it does not show up immediately but over time. Hit or miss, comes and goes, the axle may be turning in the cradle, continuously changing the working angle of the driveshaft. Is it possible?

It would definitely allow the the rear end to rotate up and down more than typical but the spring perch with the centering hole is welded to the axle tube so torquing them to the proper setting should center the axle back on the perch. although the more things you measure on these trucks I don't think there is anything that is level, plumb, square, round, flat, flush, aligned, concentric or balanced, so it's a huge assumption the perches are aligned and parallel. There is no doubt some slop, Fireaxxe pointed out his thrust angle changed a quarter of a degree by loosening things changing the working angle, then putting everything back where it was and re-torquing everything. An alignment shop can tell you what the thrust angle is, they are usually small and require laser equipment to measure.

[Jesse Davidson]

Maybe you should try a bottle of smart water instead of aquafina. J/k gotta keep a sense of humor with these trucks though otherwise they'll drive you nuts. I'll do the water bottle test on my 5.3 this weekend and take a quick video. What rpm does the 4.3 idle at? My 5.3 idles at just a tick over 450 RPM.

hahahaha yea, I think these trucks have already driven everyone nuts.

 

ummmm good question, I didn't look, I want to say its about the same maybe closer to 500, but I could be wrong with that. My truck is at the dealer for the third time now so I can't even check until I get it back likely unfixed.

Did you see my post about the new recalls? thought that was pretty interesting... 4x4 kicks in by its self in the cold and grinds hahaha what a f*cking piece of shit this truck has turned out to be.

Edited September 22, 2015 by Jesse D

[abominable z71]

hahahaha yea, I think these trucks have already driven everyone nuts.

 

ummmm good question, I didn't look, I want to say its about the same maybe closer to 500, but I could be wrong with that. My truck is at the dealer for the third time now so I can't even check until I get it back likely unfixed.

Did you see my post about the new recalls? thought that was pretty interesting... 4x4 kicks in by its self in the cold and grinds hahaha what a f*cking piece of shit this truck has turned out to be.

Yeah I read that, thought it was interesting because I noticed the vibration was typically worse when it is cold. Do you have anymore info on it. Does the switch light up or does it notify you in the cluster that there is a 4wd shit in progress? I wonder if it does it without any indication that it's happening.

 

My u-bolts were loose when I checked them took about 1-1/2 turns to get them to 75 ft-lbs, didn't affect the vibes though.

 

I have noticed something that bdkfl mentioned when they were test driving new trucks, that trucks that tended to vibrate at freeway speeds also had a vibration at 4500 rpm when you put your foot into it, I have noticed my truck vibrates at 4500 when I get on it and that it vibrates at highway speeds, trying to decipher what that might mean. There is no doubt a cause for this and either GM can't find it or they know what it is and it's an expensive fix so they will just fight it out hoping the owner will give up. Either way it's a bunch of bull$h!t

[Jesse Davidson]

Yeah I read that, thought it was interesting because I noticed the vibration was typically worse when it is cold. Do you have anymore info on it. Does the switch light up or does it notify you in the cluster that there is a 4wd shit in progress? I wonder if it does it without any indication that it's happening.

 

My u-bolts were loose when I checked them took about 1-1/2 turns to get them to 75 ft-lbs, didn't affect the vibes though.

 

I have noticed something that bdkfl mentioned when they were test driving new trucks, that trucks that tended to vibrate at freeway speeds also had a vibration at 4500 rpm when you put your foot into it, I have noticed my truck vibrates at 4500 when I get on it and that it vibrates at highway speeds, trying to decipher what that might mean. There is no doubt a cause for this and either GM can't find it or they know what it is and it's an expensive fix so they will just fight it out hoping the owner will give up. Either way it's a bunch of bull$h!t

My understanding of it, is that there is no indication that it is going into 4x4, it just does it. I can say that I don't know for sure that it has happened to me (I actually don't think it has), but when I put it in 4 high myself today leaving the job site, there was a squeal/ grinding noise. My service writer says that this is the indication the truck has the problem.

 

Yea, I did see you discussing the working angles and stuff. honestly I understand the theory, but checking it fixing it is a bit over my head right now. I may be a mechanical engineer, but I'm no mechanic, I basically know enough to be dangerous haha.

 

I find it hard to believe that GM hasn't figured it out yet, they have enough techs, engineers etc. that they should have figured it out since the '14s started coming in with it. I think its just too expensive for them to want to fix.

 

I really hope they made the adjustments in the '16s instead of just trying to hide it (I wonder how we can try to find that out), as I am really feeling that I may end up in one. I'm driving a lot more now with my new job, and don't have the time I did before to deal with fighting this, and quite honestly I am beyond done dealing with it.... And I havn't even tried to do the amount of the stuff you have...

 

Does anyone happen to know if the 8 speed they are going to use on the 5.3 is the same on they are currently using on the 6.2? If it is, do we think it will work properly? As the 6.2 currently has vibration issues as well.

[14silverado4.3]

Jesse D:

 

Rough Idle in Drive

September 15, 2015

Some 2015 Silverado 1500, Suburban, Tahoe, Sierra 1500, Yukon models, Escalade models; 2014 Silverado 1500 and Sierra 1500 models equipped with 4.3L, 5.3L, or 6.2L engines (RPOs L83, L86, LV1, LV3) may have a rough idle and/or vibration at idle in Drive. This condition may be most noticeable following extended driving, while idling at a stop in Drive. It will not be present in Park, Reverse, or Neutral.

 

 

 

There will not be any DTCs with this condition. Use the CH-51450-A (Pico Oscilloscope) for diagnosis. With the tool’s accelerometer positioned on forward end of the seat track, the condition will show in the lateral/cross-car direction as E1.5 (1.5 engine order) in the range of 2–7 mg.

 

 

 

This rough idle condition may be improved by performing a motor mount adjustment procedure. The mount adjustment procedure addresses the normal idle characteristics of the Gen-5 V6 and V8 engines transmitted through ground-out in the motor mounts due to frame bracket positioning tolerances.

 

 

 

TIP: Perform the following procedure on both left and right engine mounts at the same time so there is no binding/twisting in the mounts.

 

 

 

Begin by removing the front wheels and wheelhouse liners. Loosen the engine mount bolts at three frame attachment points for both the left and right mounts. (Fig. 13) Also loosen the transmission mount to keep from putting it into a bind. Lift the engine so both mounts are off the frame approximately 10-20mm.

 

 

 

Install 3mm-thick spacers between the bottom surface of the mount and frame bracket, on the inboard side of mount. Do not use tapered shims. Use a small amount of adhesive to hold the spacers in place on the frame.

 

 

 

Installing spacers between the mount and frame bracket at the lower inboard location, (Fig. 14, #1) alleviates the ground-out in the mount at the upper outboard area. (Fig. 14, #2)

 

Lower the engine so the spacers are trapped between the mount and the frame and tighten the bolts. Tighten the center/upper bolt first; then the front and rear bolt. Torque the mounts to 50 Nm (37 lb.-ft.).

 

 

 

For additional information, refer to #PIP5211.

Edited September 22, 2015 by 14silverado4.3

[4x4LJB]

Well...I've paid close attention to this topic. Obviously, as I am contemplating a new 2015 Sierra SLT.

 

Dealer called me and said he has a loaded black 2015 SLT Sierra for sale at a good price.

 

I told him I would only buy the truck after I test drove it. Told him, and his sales manager, about this forum and topic.

 

Test drove it. Has a pronounced shake at 60 to 67 mph. Tapers off after that.

 

Told him to find another one; not going to buy it, no matter what the price is. Too bad, it's a loaded black leather with black exterior. Nice truck.

 

I've driven four 2015 GMC Sierras off the dealer lots. Two have an oscillation or shake.

 

Geesh. What's a buyer to do?

 

Lee

 

[Jesse Davidson]

Jesse D:

 

Rough Idle in Drive

September 15, 2015

Some 2015 Silverado 1500, Suburban, Tahoe, Sierra 1500, Yukon models, Escalade models; 2014 Silverado 1500 and Sierra 1500 models equipped with 4.3L, 5.3L, or 6.2L engines (RPOs L83, L86, LV1, LV3) may have a rough idle and/or vibration at idle in Drive. This condition may be most noticeable following extended driving, while idling at a stop in Drive. It will not be present in Park, Reverse, or Neutral.

 

 

 

There will not be any DTCs with this condition. Use the CH-51450-A (Pico Oscilloscope) for diagnosis. With the tool’s accelerometer positioned on forward end of the seat track, the condition will show in the lateral/cross-car direction as E1.5 (1.5 engine order) in the range of 2–7 mg.

 

 

 

This rough idle condition may be improved by performing a motor mount adjustment procedure. The mount adjustment procedure addresses the normal idle characteristics of the Gen-5 V6 and V8 engines transmitted through ground-out in the motor mounts due to frame bracket positioning tolerances.

 

 

 

TIP: Perform the following procedure on both left and right engine mounts at the same time so there is no binding/twisting in the mounts.

 

 

 

Begin by removing the front wheels and wheelhouse liners. Loosen the engine mount bolts at three frame attachment points for both the left and right mounts. (Fig. 13) Also loosen the transmission mount to keep from putting it into a bind. Lift the engine so both mounts are off the frame approximately 10-20mm.

 

 

 

Install 3mm-thick spacers between the bottom surface of the mount and frame bracket, on the inboard side of mount. Do not use tapered shims. Use a small amount of adhesive to hold the spacers in place on the frame.

 

 

 

Installing spacers between the mount and frame bracket at the lower inboard location, (Fig. 14, #1) alleviates the ground-out in the mount at the upper outboard area. (Fig. 14, #2)

 

Lower the engine so the spacers are trapped between the mount and the frame and tighten the bolts. Tighten the center/upper bolt first; then the front and rear bolt. Torque the mounts to 50 Nm (37 lb.-ft.).

 

 

 

For additional information, refer to #PIP5211.

This is what I have, and while I appreciate that post, there is clearly a vibration at idle when in park, otherwise the water wouldn't have been moving like that. any other ideas?

 

Condition 6: Vibration Felt at Idle Only

• Refer to the PIP5137A: Rough Idle or Vibration In Drive.

Other Sources of Vibrations

1. Exhaust resonance – PI1201A: Exhaust Rattle, Buzz, Pop or Whistle.
2. Vibration during active fuel management V4 mode operation – PIP5228. Follow this cab mount settling procedure listed below:

   Warning: When settling the body cushions, do NOT separate the frame from the body more than is necessary. Possible personal injury and damage to multiple parts may result if you do not follow the guides outlined below:

   • Intermediate steering shaft – Do not allow the shaft to extend more than 25 mm (1 in).
   • Fuel tank filler hose – Do not stretch the hose excessively.
   • Tail/Turn signal lamp wiring/rear lamps junction block – Leave slack in the wires
   • Park brake cable – Leave slack in the cable
   • Body ground straps – Leave slack in the wire
     • The technician should first loosen the fastener located at the center of each body mount (6 for a regular cab, 8 for crew and double cab).
     • Using a large angled pry bar, lift up the cab body slightly to settle / relax it. Perform this at each mount location one at a time.
     • Repeat this cab mount settling process twice, to confirm the mounts are settled / relaxed.Visually verify that the cab to box alignment is correct before re-torqueing all mounts to specification found in Service Information, body repair, frame and under body section.The cab / body mount position locationThe numbers in the picture below indicate the specific mount position. The mounts on the passenger side of the vehicle are identified the same way. This will assist the technician to identify the correct location of each mount so they can be torque to the proper specification.

       1 = body mount cushion front2 = body mount cushion position number 13 = body mount cushion position number 24 = body mountcushion position number 3

3. Pitchline runout – Pitchline runout will normally show as a 1st order tirevibration on the PicoScope. If after correcting tire(s) with excessive Road Force, a vibration exists, remove differential cover and check ring gear backlash. Every tooth should be checked for excessive backlash. If there is more than 0.0762 mm (0.003 in) of variation, the ring gear and/ordifferential should be replaced to correct the condition (SI Document ID# 3269088, 3620298) (PIP4148A).

    

4. Backlash Adjustment Procedure

   Special Tools:

   • J-8001 Dial Indicator Set
   • J-25025 Guide Pins

   Note:

   • Ensure that the side bearing surfaces in the axle housing are clean and free of burrs. If the original bearings are to be reused, the original bearing cupsmust also be used.
   • The differential side bearings must be initially preloaded in order to determine the backlash of the gear set. After the backlash is set, the finalbearing preload is set.
   • Mark the bearing caps left or right sides.
   1. Measure the rotating torque of the drive pinion and differential assembly. Refer to the Differential Drive Pinion Gear Bearing Replacement in SI.

   

   1. Install the J-25025 pins and the J-8001 indicator to the axle housing.

      Note: Preload the dial of the J-8001-3 indicator approximately ¾ of a turn and zero the gauge.Note: The illustration above is for reference only. The differential does NOT need to be removed from the vehicle.

   2. Set the J-8001-3 indicator (1) so that the stem is aligned with the gear rotation (1) and square to the tooth angle.
   3. Hold the drive pinion stationary and move the ring gear back and forth.
   4. Repeat the measuring procedure at each tooth around the ring gear.
   5. The difference between the backlash at all of the measuring points should not vary by more than 0.05 mm (0.002 in).
   6. If the difference between the backlash at all of the measuring points varies by more than 0.05 mm (0.002 in), inspect for burrs, a distorted case flange or uneven bolting.
   7. If the difference between all the measuring points is within specifications, the backlash at the minimum lash point measured should be 0.08-0.25 mm (0.003-0.010 in) with a preferred backlash of 0.13-0.18 mm (0.005-0.007 in).

      Note:

      1. Install the selected shim.

         Caution: Use the correct fastener in the correct location. Replacementfasteners must be the correct part number for that application. Do not use paints, lubricants, or corrosion inhibitors on fasteners, or fastener joint surfaces, unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems. When using fasteners that are threaded directly into plastic, use extreme care not to strip the mating plastic part(s). Use hand tools only, and do not use any kind of impact or power tools.Fastener should be hand tightened, fully seated, and not stripped.

      2. If the backlash is to small, increase the backlash using the following procedure:
         1. Remove the bearing cap bolts and the bearing caps.

            Note: Mark the bearing cups and the shims left or right.

         2. Remove the differential case assembly with the bearing cups and theshims.Note: Measure the production shim or the shim and service spacer in 3 locations.Measure each shim separately.
         3. Measure the thickness of left side shim pack.

            Note: If the original shim is cast iron production shim, assemble theshim pack using a service spacer and service shims. For example, to increase the backlash by 0.05 mm (0.002 in), remove 0.10 mm (0.004 in) in of thickness from the left side shim pack.

         4. Calculate the average of the 3 measurements for each shim.

            Note: If the original shim is cast iron production shim, assemble theshim pack using a service spacer and service shims. For example, to increase the backlash by 0.05 mm (0.002 in), remove 0.10 mm (0.004 in)  of thickness from the left side shim pack.

         5. Assemble a new left side shim pack by decreasing the appropriate amount of thickness from the original left side shim pack.

            Note: Measure each shim separately.

         6. Measure the thickness of right side shim or the shim and service spacer in 3 locations.

            Note: Add the average of each of the shim measurements together. Record the measurement. This is the thickness for the right side shimpack.

         7. Calculate the average of the 3 measurements for each shim.
         8. Assemble a new right side shim pack by increasing the appropriate amount of thickness to the original right side shim pack. If the originalshim is cast iron production shim, assemble the shim pack using a service spacer and service shims. For example, to increase the backlash by 0.05 mm (0.002 in), add 0.10 mm (0.004 in) of thickness to the right side shim pack.
   8. • Increasing or decreasing the shim thickness by 0.05 mm (0.002 in) will change the backlash adjustment approximately 0.03 mm (0.001 in).
      • If the backlash is less than, select a smaller shim than the one that was removed. For example, to INCREASE the backlash by 0.05 mm (0.002 in), select a shim that is 0.10 mm (0.004 in) thinner than the shim that was removed.
      • If the backlash is larger than, select a larger shim than the one that was removed. For example, to DECREASE the backlash by 0.05 mm (0.002 in), select a shim that is 0.10 mm (0.004 in) thicker than the shim that was removed.

         

        3. Use the following procedure to decrease the backlash if the backlash is too large:
           1. Remove the bearing cap bolts and the bearing caps.

              Note: Mark the bearing cups and the shims left or right.

           2. Remove the differential case assembly with the bearing cups and theshims.

              Note: Measure the production shim or the shim and service spacer in 3 locations. Measure each shim separately.

           3. Measure the thickness of left side shim pack.

              Note: Add the average of each of the shim measurements together. Record the measurement. This is the thickness for the left side shimpack.

           4. Calculate the average of the 3 measurements for each shim.
           5. Assemble a new left side shim pack by increasing the appropriate amount of thickness to the original left side shim pack. If the originalshim is cast iron production shim, assemble the shim pack using a service spacer and service shims. For example, to increase the backlash by 0.05 mm (0.002 in), add 0.10 mm (0.004 in) of thickness to the left side shim pack.

              Note: Measure the shim or the shim and service spacer in 3 locations. Measure each shim separately.

           6. Measure the thickness of right side shim pack.

              Note: Add the average of each of the shim measurements together. Record the measurement. This is the thickness for the right side shimpack.

           7. Calculate the average of the 3 measurements for each shim.
           8. Assemble a new right side shim pack by decreasing the appropriate amount of thickness to the original right side shim pack. If the originalshim is cast iron production shim, assemble the shim pack using a service spacer and service shims. For example, to decrease the backlash by 0.05 mm (0.002 in), remove 0.10 mm (0.004 in) of thickness to the right side shim pack.
        4. Install the differential case assembly with the bearing cups.
        5. Install the left side service shims between the axle housing and thedifferential case.
        6. Install the right side service shims between the axle housing and thedifferential case.

           

Note: The service spacers must be installed between the service shim(s) and the axle housing.

• Using the brass drift for 9.5/9.76 axle, install the left side service spacer.
• Recheck the backlash and adjust, if necessary.
• Install the bearing caps and bolts and tighten to 85 Y (63 lb ft).
• Recheck the backlash and adjust, if necessary.
• Once backlash is correct, perform a gear tooth contact pattern check in order to ensure proper alignment between the ring and pinion gears. Refer to the Gear Tooth Contact Pattern Inspection in SI.

  Note: Recheck the backlash following the steps above to verify that the backlash is within specifications.

• Tighten the differential bearing cap bolts to 85 Nm (63 lb ft).
• Measure the drive pinion and differential case side bearing preload and adjust, if necessary following the steps above.
• Once the backlash and bearing preload is correct, perform a gear tooth contact pattern check in order to ensure proper alignment between the ring and pinion gears. Refer to the Gear Tooth Contact Pattern Inspection in SI.

Once all areas of vibrations has been reduced, if there is still vibration that the customer is concerned about, the following diagnosis maybe helpful to determine if a shock issue exists.

Warning: The following items should NOT be utilized until the source of the problem has been corrected.

Potential Vibration/Rough Ride:

Condition/Concern

The shock issues below DO NOT cause a vibration, it will only make an existing vibration feel worse. In some cases, a vibration that would not normally be a customer concern may now be felt due to a bad shock. But in general, the original source of the vibration, whether it is the wheels, tires, propeller shaft, etc, will have to be corrected. When diagnosing a vibration issue, there have been reports of the shocks amplifying the vibration felt inside the truck. Engineering has found that some shocks may have been built with contaminated shock oil. This may cause the shocks to dampen incorrectly.

This only applies to the following shocks:

• Rear- Only trucks listed with the Z71 option (RPO Z71, these shocks will be white in color)

Recommendation/Instructions:

Two checks are needed to be performed to verify if the shocks could be an issue:

1. Check the date code located on the bottom of the shock. The first 8 digits are the GM part number. The next 5 digits are the supplier part number. The last 5 digits will be the date code. Any shock built before A1474 could have an issue. The date code format is as follows: 1st digit is the plant, next 3 digits are the day of the year and the last digit is the last number of the year.

Example:

1. • A14743C
   • A = Plant
   • 147 = 147th Day of the Year
   • 4 = 2014
   • 3C = Drawing Change Level
2. If the rear shocks are built before this date code, they will have to be removed for a dynamic test.

Dynamic Test (Rear Shock – Z71 option only)

Starting with a fully extended shock, compress the rod taking notice of the first 10 millimeters of travel. A good shock will not have any free play and there will be immediate resistance to being compressed. A shock with an issue will have several millimeters of free play (no resistance) before feeling the resistance from being compressed. Replace any shocks with excessive free play. In most cases, the rear shocks will be the issue.

http://oemdtc.com/6392/information-on-vibration-analysis-and-diagnostic-2014-2015-chevrolet-silverado-gmc-sierra/14