V4 to V6 shudder

[MD Chevy]

Well my truck started to get a bad vibration when switching from V4 to V6. Took it to the dealership and the service manager had no idea the 4.3 had AFM (that was a little unnerving). Regardless he took it and said he would try to pin point the problem. Got it back late last night and he said they added a new clamp on the exhaust and something with the body cab mount bolts. Hopefully this will take care of my problem. Best thing is he said him and the general manager took it for a ride and both felt exactly what I was talking about. I will give an update as to if this issue is resolved with these solutions.

Disclaimer- This is meant to be a helpful post not a whining one.

Edited November 8, 2014 by txab
edit title

[captgary]

So what was your outcome. I have the same problem with my truck. Been in the shop twice now. They've changed tires, differencial, and tacked the exhast, but it still vibrates when going from V6 to V4 mode.

[theatasigma]

So what was your outcome. I have the same problem with my truck. Been in the shop twice now. They've changed tires, differencial, and tacked the exhast, but it still vibrates when going from V6 to V4 mode.

 

I wonder if it is a harmonic balance (well imbalance) in the engine? Starting combustion on two cylinders could be whats causing this. A V6 is more harmonically balanced than a V4, even though this is a V6, you still have to account for a lack of combustion. Do you notice it more when you mash the gas or when it transitions to go up a hill or something?

[MD Chevy]

Well I had forgotten about updating this post. I took it in 3 times. On the 3rd time GM got involved. I believe the dealership was told to do 3 maybe 4 things. After all was done it still had the vibration/shutter. GM told the dealership to drive one like mine. Service manager said it had some but it was extremely minimal compared to mine. GM said it was the nature of the beast and it was normal. Dealership said all the right things but I didn't get the good freling that things were going to work out. The next day I went out and bought a Nissan Frontier.

 

Hopefully you all get treated better than I. Very frustrating to say the least!

[captgary]

 

I wonder if it is a harmonic balance (well imbalance) in the engine? Starting combustion on two cylinders could be whats causing this. A V6 is more harmonically balanced than a V4, even though this is a V6, you still have to account for a lack of combustion. Do you notice it more when you mash the gas or when it transitions to go up a hill or something?

No vibration when I accelerate and vehicle is in V6 mode. Only when the V4 mode kicks in at any speed does this occur. They've got my car right now and the service manager called me to say he was going to drive it home last night to see if it was any different. Haven't heard from him today yet........The service manager keeps going back to the exhast after changing all the other parts and says he is going to force balance the tires yet once again. He also said that the engine wasn't heavy enough to stop the vibrations....whatever that means.

I've notified the sales guy who doesn't seem to interested in helping me yet. I'm thinking this is going to go down the lemon law trail.

 

On other note I've got a 2015 Silverado LT V8 as a loaner and it rides great. It's a 2WD verses my 4WD. Stay tuned should start getting interesting.

[captgary]

Well I had forgotten about updating this post. I took it in 3 times. On the 3rd time GM got involved. I believe the dealership was told to do 3 maybe 4 things. After all was done it still had the vibration/shutter. GM told the dealership to drive one like mine. Service manager said it had some but it was extremely minimal compared to mine. GM said it was the nature of the beast and it was normal. Dealership said all the right things but I didn't get the good freling that things were going to work out. The next day I went out and bought a Nissan Frontier.

 

Hopefully you all get treated better than I. Very frustrating to say the least!

Thanks MD...we will see. I do have to say the service manager is doing a lot to try and fix it, but so far after 2 service trips and 24 days there they haven't got a clue as to why. They just keep throwing parts at it hoping that will fix it.

 

I say hopeful.

[MD Chevy]

I hope for you CaptGary. It was pretty hard to walk away from GM. But I used it as a DD and the shutter bothered me like crazy. My wife was pretty upset about the situation so she supported me 100%. She loves the frontier...especially being smaller (has more room for my son in the back though).

 

My brother has a 2014 crew cab 4x4 V8 and his is super smooth in the transition. Obviously mine came out of factory specs, they just weren't willing to fix it for me. Poor customer service if you ask me!

[Brian S.]

I had a 2014 4.3l last year and it vibrated between about 15 and 35mph while in Auto 4wd, otherwise it was pretty good. I always thought it was a kind of a dead spot where the gearing was tuned more for mpg than performance.

Edited April 30, 2015 by Brian S.

[captgary]

UPDATE.....The service manager called me yesterday saying he had a request into the zone manager to put a new set of tires on the truck that aren't goodyear. Not sure this will help but they keep throwing parts at what I think is a engine issue......V6 to V4 mode. At least they are still trying to fix the issue. Of course I called my sales guy who sold me the truck and he never returned my call.

 

We will see.

[captgary]

OK looks like the dealership is going to work with me on a buy back. But it will have to go through GM. The general manager went with me to talk to the service manager who said he had already reported the issue to GM zone manager. Now I have to call GM to file a complaint.

 

Any advise out there?

[Rick35]

I'm getting a shudder in my 2014 Silverado when the engine goes from V4 to V6. I've been to the dealer twice and now we're waiting for Field Service to contact the dealer about when they'll be in the area to check my truck. Its been a couple of weeks and still nothing from GM. The dealer tried a couple of things and if anything only made it worse. I'm getting very upset about the lack of communication with GM to the dealer. I haven't contacted GM directly yet as I'm not sure that will do. The dealer service has been good and I think they're doing the best they can. Any ideas?

[Brian S.]

GM should think about a chip that disables AFM for the 4.3l. Cheaper than buy backs, and the 4.3l is a good engine that probably doesn't gain a lot of mpg dropping to 4 cylinders.

[tstodda]

Well this is my first post, I am joining to contribute and not be the guy who reads everything and never posts anymore .

 

I had a '14 Sierra Crew with the 4.3 that I traded in with assistance from GM, so a somewhat 'buy-back' just a few weeks back now.

 

Prior to moving into a new truck I had a couple requests regarding the issue and I was willing to keep the GMC:

 

1) Continue to warranty the shutter after the 3yr/36k warranty: I was told this was not an option, the repair usually only lasted a few weeks anyways.

2) Disable AFM: Also told this was not an option. Between myself and the fence post if I had to live with it I was going to either have it tuned out, or buy the Range AFM delete after the warranty period.

 

When my trade in assistance was approved it was strictly implied that my replacement truck needs to have a V8. They know it is an issue with the 4.3.

 

My advice is to contact GM directly about the issue, it is well known IMO. I did it with little expectation and actually had a choice to make within a few weeks, I did have to be persistent on the phone call but everything else went smooth.

 

The beauty is you get a case # from GM and can reference that on your CSI surveys after service...really helps the process move along.

[Rick35]

What was the trade-in assistance if you don't mind me asking.

[tstodda]

What was the trade-in assistance if you don't mind me asking.

 

PM sent! I dont want to leave this thread 'hanging'