Two Vibrations in 2011 5.3

[kleine_zwiebeln]

There are two different vibration events that I'm trying to sort out on my 2011 1500 LTZ 5.3 4x4. Truck has 190,000 miles and has been well maintained following the factory service schedule.

 

The first is when I apply very light throttle at 30-45 mph. The truck acts like it is lugging in 6th gear then it behaves fine once the transmission kicks down. Is this AFM related or a transmission issue? 

 

The second is more of a pulsating vibration at around 65 mph. The vibration comes and goes about once per second and doesn't seem noticeable above 70 mph. Not a constant vibration like what an unbalanced wheel feels like.

 

Any advice? 

[CamGTP]

Both kinda sound torque converter related.

 

If you got 190,000 miles from the stock 6L80e and converter, you did well.

[kleine_zwiebeln]

I've also noticed when I cold start and shift from park to drive the truck tends to lurch forward slightly, unless I'm firmly pressing the brake pedal. Not sure if that's normal or a possible torque converter issue as well.

[swathdiver]

On 9/18/2020 at 9:24 PM, kleine_zwiebeln said:

There are two different vibration events that I'm trying to sort out on my 2011 1500 LTZ 5.3 4x4. Truck has 190,000 miles and has been well maintained following the factory service schedule.

 

The first is when I apply very light throttle at 30-45 mph. The truck acts like it is lugging in 6th gear then it behaves fine once the transmission kicks down. Is this AFM related or a transmission issue? 

 

The second is more of a pulsating vibration at around 65 mph. The vibration comes and goes about once per second and doesn't seem noticeable above 70 mph. Not a constant vibration like what an unbalanced wheel feels like.

 

Any advice? 

Assuming you have 3.42 gears, at 30 mph your still in 5th gear until right before 40 mph.  On mine the rpms are around 1000, no more AFM on mine.

 

The other could be tires need balancing or maybe it's time to open the rear cover and inspect the ring and pinion and spider gears.

[kleine_zwiebeln]

On 9/20/2020 at 7:34 PM, swathdiver said:

Assuming you have 3.42 gears, at 30 mph your still in 5th gear until right before 40 mph.  On mine the rpms are around 1000, no more AFM on mine.

 

The other could be tires need balancing or maybe it's time to open the rear cover and inspect the ring and pinion and spider gears.

 

Both issues are still present after switching to new tires and wheels.

 

Are you saying the low speed vibration is or is not AFM related?

[swathdiver]

On 9/30/2020 at 9:00 PM, kleine_zwiebeln said:

 

Both issues are still present after switching to new tires and wheels.

 

Are you saying the low speed vibration is or is not AFM related?

Doubt it has anything to do with AFM, check your differentials.  Including the front mounts for it which also wear out.  The best part of my BlackBear tune is how the transmission performs now, no lugging.  Mine also has rhythmic noises which I attribute to my front differential, either the ring and pinion or the bearings on either side.  It's loudest in the 40s.  

Edited October 4, 2020 by swathdiver