iamdub
Full Access Member
Mine did the exact same thing. Disabling AFM fixed the shuttering when slowing to a stop. I eventually upgraded to the H3 mounts, though.
2009 PPV Vibrations in Steering-wheel & Under Truck (Slowing Down)
- Thread starter balln2k11
- Start date
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Mine did the exact same thing. Disabling AFM fixed the shuttering when slowing to a stop. I eventually upgraded to the H3 mounts, though.
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
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
Full Access Member
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
Full Access Member
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
TYF Newbie
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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".
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 $$$$ worth.
On the DiabloSport website, there are reviews of others who had the same problem + the exhaust rattle.
After changing a bunch of stuff and checking steering/suspension and drive-line items, I put my DIC into "Instant MPG" and drove around. The issue only happened when slowing down to around 25-20 mph. I noticed I would be in V8 mode, then brake, then notice it would go into V4 mode... that is where the shakes would happen, until about 19MPH when it would go back into V8 mode.
The fix (or band-aid), disable the AFM (AKA - DOD). I had a new DiabloSport GM Programmer sitting in a box, which I loaded a random tune to it (disabling AFM) and no more V4 mode or shakes. Now I need to mess with my DiabloSport Programmer to get my $$$$ worth.
On the DiabloSport website, there are reviews of others who had the same problem + the exhaust rattle.
iamdub
Full Access Member
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.
