2009 PPV Vibrations in Steering-wheel & Under Truck (Slowing Down)

[balln2k11]

I have been working on making my ride softer (almost there) and cutting down on road noise. So far with the dynomat of the entire truck (including behind headliner) and adding the factory carpet, the drive is getting much better, just still hate the vibrations.

This biggest issue i have had and getting worse is when slowing down at around 20-25 mph, the truck shakes a little and vibrates my steering. I thought it had to be my brakes, so I just replaced the rotors and pads (greased up the calipers guides). Then thought it was the engine transmission mounts (they were bad), but didn’t help. Also replaced shocks (for smoother ride), tie-rods, sway bar bushings (and end-links), and I’m sure other stuff.

What could be causing this rattle/vibration when slowing down (even does when not touching the brakes and just coasting)? Could it be the driveline or transmission? I try and stay away form shops on this project, but even they said it could be a ton of stuff.

 

[Doubeleive]

wheels/tires

 

[balln2k11]

wheels/tires

I have OEM 20” wheels. 275/55/20.

 

[iamdub]

It only does it when decelerating and you get around 20-25 MPH? What about slowly accelerating and you reach 20-25 and hold it steady? Hold it steady at that speed where it's worst, then lightly accelerate and note what happens. Return to the offending speed and hold steady, then lightly apply the brake while keeping the accelerator pressed where it is and note what happens.

Because it shakes the steering wheel, I'm gonna agree with Wes and say you should investigate the wheels and tires. Maybe a bad tire? Swap the back and front wheels and see if it changes any.

 

[balln2k11]

It only does it when decelerating and you get around 20-25 MPH? What about slowly accelerating and you reach 20-25 and hold it steady? Hold it steady at that speed where it's worst, then lightly accelerate and note what happens. Return to the offending speed and hold steady, then lightly apply the brake while keeping the accelerator pressed where it is and note what happens.

Because it shakes the steering wheel, I'm gonna agree with Wes and say you should investigate the wheels and tires. Maybe a bad tire? Swap the back and front wheels and see if it changes any.

Yea i only get the vibration when slowing down not accelerating. It only happens around 20-25 mph. No issues on the freeway at normal driving. The steering wheel vibration isn’t too bad, its the rear of my car i feel it the most and rattles my rear hatch the most. Might have to get a GoPro and place under truck and drive around.

I will have to try it some more, but when i was driving home today I decided to slow down and drop into neutral and didn’t notice the issue. It’s going to drive me nuts.

 

[iamdub]

So, when it's doing it, you can blip the throttle (just enough to apply power but not accelerate out of the trouble MPH range) and it stops, but comes back as soon as you let off the throttle? If so, I'm leaning towards worn U-joints or gears in the diff at this point.

 

[balln2k11]

So, when it's doing it, you can blip the throttle (just enough to apply power but not accelerate out of the trouble MPH range) and it stops, but comes back as soon as you let off the throttle? If so, I'm leaning towards worn U-joints or gears in the diff at this point.

I’m going to check the driveline. No clue how to check the rear diff. It’s almost like once it downshifts into 2nd gear I’m getting the issue. I only have the 4-Speed trans, even though the civilians had 6-speeds in 2009

 

[Doubeleive]

I meant the problem could be wheels/tire not what they were, but besides that I would take a good look at your pinion bearing in addition to the u-joints like chris mentioned, if the rear diff is leaking anywhere that's a potential indicator of internal problems.

 

[BG1988]

I have been working on making my ride softer (almost there) and cutting down on road noise. So far with the dynomat of the entire truck (including behind headliner) and adding the factory carpet, the drive is getting much better, just still hate the vibrations.

This biggest issue i have had and getting worse is when slowing down at around 20-25 mph, the truck shakes a little and vibrates my steering. I thought it had to be my brakes, so I just replaced the rotors and pads (greased up the calipers guides). Then thought it was the engine transmission mounts (they were bad), but didn’t help. Also replaced shocks (for smoother ride), tie-rods, sway bar bushings (and end-links), and I’m sure other stuff.

What could be causing this rattle/vibration when slowing down (even does when not touching the brakes and just coasting)? Could it be the driveline or transmission? I try and stay away form shops on this project, but even they said it could be a ton of stuff.

check the bushings, they might be bad on the steering rack


Jeep Death Wobble

 

[CrashTestDummy]

Our '10 PPV used to shudder a bit when slowing to a stop. It was the driver side motor mount. The metal in the motor mount was resting on the K-member and when slowing, the engine being in 4-cyl mode with the converter locked would cause a shudder, or shake, that was felt thorugh the dash and wheel.

Replacing the driver side motor mount fixed that. You can still feel the truck in that mode as you slow, but the felt-shudder is significantly reduced.

 

[iamdub]

Our '10 PPV used to shudder a bit when slowing to a stop. It was the driver side motor mount. The metal in the motor mount was resting on the K-member and when slowing, the engine being in 4-cyl mode with the converter locked would cause a shudder, or shake, that was felt thorugh the dash and wheel.

Replacing the driver side motor mount fixed that. You can still feel the truck in that mode as you slow, but the felt-shudder is significantly reduced.

Mine did the exact same thing. Disabling AFM fixed the shuttering when slowing to a stop. I eventually upgraded to the H3 mounts, though.

 

[balln2k11]

I replaced the driver motor mount about 4 months ago. Maybe being generic brand is causing the issue? I also replaced the transmission mount (using AC/Delco).

Would I just use my Diablo Programmer to turn off the AFM? I don't see the truck switching from V4 to V8 very much.

Again it;s only at around 20mph-25mph when slowing down and feels like the transmission is shifting down. It does shift harsh. I checked the U-Joints and they are solid, no play.

It does look like a have a newer driveline? it's bright aluminum, while the u-joints and more rusty looking. I live in Las Vegas, so we don't have rusty cars.

Thank you everyone for the help, I really appreciate the help

 

[iamdub]

I replaced the driver motor mount about 4 months ago. Maybe being generic brand is causing the issue? I also replaced the transmission mount (using AC/Delco).

Would I just use my Diablo Programmer to turn off the AFM? I don't see the truck switching from V4 to V8 very much.

Again it;s only at around 20mph-25mph when slowing down and feels like the transmission is shifting down. It does shift harsh. I checked the U-Joints and they are solid, no play.

It does look like a have a newer driveline? it's bright aluminum, while the u-joints and more rusty looking. I live in Las Vegas, so we don't have rusty cars.

Thank you everyone for the help, I really appreciate the help

20-25 just sounds too fast for that common AFM shudder. It does it when it's still in 4 cyl. mode and you're just about stopped, like a car with a manual trans does when you're slowing to a stop in gear and it almost stalls so you push the clutch in.

But it's certainly worth trying it as a troubleshoot if you have the means to disable it so easily. BTW, since yours doesn't go into 4 cyl. mode much, I'd strongly recommend disabling AFM and leaving it off.

 

[RichardCranium]

Shift into neutral from road speed and see if the shudder still exists, that could eliminate a lot of the drivetrain. This is also when it helps to have a buddy you can also swap wheels/tires with for the length of a test drive. Even though you feel confident with your own setup, it never hurts to try especially if you have a buddy with a Tahoe/Avalanche/Silverado/etc you can swap shoes with.

 

[Kathnrich1]

Replace your two front rotors. Every time any of my new Tahoe's or Yukon XL or Suburban had the front shakes on slowing down, has ALWAYS been the front rotors. Try spending a little more money on a brand name I. E. ACDELCO and such. Always get "Heavy Duty".

 

[balln2k11]

So I solved the riddle (wish I would have asked the forum before changes my perfectly good pads and rotors). Thank you to everyone who chimed in.

After changing a bunch of stuff and checking steering/suspension and drive-line items, I put my DIC into "Instant MPG" and drove around. The issue only happened when slowing down to around 25-20 mph. I noticed I would be in V8 mode, then brake, then notice it would go into V4 mode... that is where the shakes would happen, until about 19MPH when it would go back into V8 mode.

The fix (or band-aid), disable the AFM (AKA - DOD). I had a new DiabloSport GM Programmer sitting in a box, which I loaded a random tune to it (disabling AFM) and no more V4 mode or shakes. Now I need to mess with my DiabloSport Programmer to get my $$$$ worth.

On the DiabloSport website, there are reviews of others who had the same problem + the exhaust rattle.

 

[iamdub]

Totally different shake than what I was picturing. Mine did it, but I always thought it was at a much lower speed than ~20 MPH. Glad you got it figured out! Keep your oil clean and listen out for a lifter ticking.