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Discussion Starter · #1 ·
2014 Terrain 60,000 Mi. Vehicles Vibrates For 3-5 Secs. Feels Like I'm Driving Over Rumbles Strips. Has Done This About a Dozen Times in (3) Months. Is Starting to Concern Me. OBDII Codes Checks Showed "No" Active Codes From "Any" System (or) "Any" Stored Codes in Memory. Afraid to Take Vehicle on "Long" Trip. 2014 Terrain 3.6L 6T70 Tansmission AWD. Any Experiences or Advice For Fix and/or Problem Will Be Appreciated.
 

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We have an 09 Toyota Matrix where I work that did what you described. We had to replace the torque converter in the transmission. $2600 at the dealership.

I would also look at wheel bearings and make sure the CV joints in your driveshafts are good to go.
 

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2014 Terrain 60,000 Mi. Vehicles Vibrates For 3-5 Secs. Feels Like I'm Driving Over Rumbles Strips. Has Done This About a Dozen Times in (3) Months. Is Starting to Concern Me. OBDII Codes Checks Showed "No" Active Codes From "Any" System (or) "Any" Stored Codes in Memory. Afraid to Take Vehicle on "Long" Trip. 2014 Terrain 3.6L 6T70 Tansmission AWD. Any Experiences or Advice For Fix and/or Problem Will Be Appreciated.

I would first do a triple drain/fill with some good Dexron certified fluid. GM is now using Mobil 1 Dexron VI. Easy to do on a 6T70. Just measure what you take out and fill with same quantity. There procedure can be found on many Youtube videos in vehicles that use the same family of tranmissions.
 

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does this while standing still or moving?
on cold engine start or once engine is up to operating temp?

My 3.6 Nox is approaching 70,000
This morning- it was cold. Well cold for California.
Started the car- and while it was revving high- we felt some vibrations.
Wife in the passenger seat asked-- whats that vibration?

I said- its probably misfiring.
I grabbed my scanner and checked-
No set or Pending codes....

But Cyl 6 showed 146 misfires.

Once warm and driven 30 miles- the misfires were no longer showing.
Im at 3% Oil life left..... so its time for a bottle of Techron.... which I did add from my stash.
I filled up the tank and told wife not to add any fuel-- until this tank is all used up.
Ill change oil next weekend.
I think its just some carbon buildup on Cyl #6 since its been over 6000 miles since the last bottle of Techron...
carbon buildup misfires tend to make themselves known on cold engine starts. (there is a bulletin on this).
 

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Take a look at this video





does this while standing still or moving?
on cold engine start or once engine is up to operating temp?

My 3.6 Nox is approaching 70,000
This morning- it was cold. Well cold for California.
Started the car- and while it was revving high- we felt some vibrations.
Wife in the passenger seat asked-- whats that vibration?

I said- its probably misfiring.
I grabbed my scanner and checked-
No set or Pending codes....

But Cyl 6 showed 146 misfires.

Once warm and driven 30 miles- the misfires were no longer showing.
Im at 3% Oil life left..... so its time for a bottle of Techron.... which I did add from my stash.
I filled up the tank and told wife not to add any fuel-- until this tank is all used up.
Ill change oil next weekend.
I think its just some carbon buildup on Cyl #6 since its been over 6000 miles since the last bottle of Techron...
carbon buildup misfires tend to make themselves known on cold engine starts. (there is a bulletin on this).
 

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The seafoam seems to make my 2.4 run smoother. The Techron worked in my 2011 5.3 but i don't think it does anything for my 2.4L and I even put in 91 octane the last time i run a bottle thru.
 

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Mine has a shimyat 1500 rpms, and no code, and I have a ticking noise that I can hear from top of engine and also from inside.
Dealer told me ticking is injector pumps, but it is louder somethimes
And shimy/misfire is only at 1500-2000, in gear or out
 

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Discussion Starter · #8 ·
So far has only done it between 35-65mph. After vehicle @ operating temperature. Has done it on highway with cruise on or off @ appox. 60-65mph. Also, has done it on local ride out in the country @ approx. 35-45mph. Did it 1st time (3) months ago. Then never again, until past few weeks.
 

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What you want to do, is use Techron regularly (regularly being at or near oil change intervals).
To help clean up the carbon in the cylinder and around the valves sealing surfaces. (On these engines- not so much for the TOP of the valves)
In my case at every oil change- to remove buildup that is 3000-7000 miles old.
You try to keep the bad stuff from building up severely to the point that you need a service visit.


I have good experience with it.
Example- on the early Trailblazers with the inline 6. 4200 Vortec.
These were prone to Cold carbon knock. On cold engine starts-- they knock. Lots of folks described it as piston slap.
On my Trailblazer-- it would start to knock nearing the 10,000 mile mark (pretty much near my oil change interval).
Once the engine was warm--- the engine was smooth and quiet.

A bottle of techron would clean up that carbon-- and significantly quiet down the knock or get rid of it.
Repeat 10,000 miles later at next oil change.



Owners manual actually calls for using this product- especially if Top Tier fuel is not used. Under FUEL Additives.
(also- GM's service bulletin for severe carbon- calls for using top end cleaner- and then running a bottle of this to finish cleaning up )
 
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So far has only done it between 35-65mph. After vehicle @ operating temperature. Has done it on highway with cruise on or off @ appox. 60-65mph. Also, has done it on local ride out in the country @ approx. 35-45mph. Did it 1st time (3) months ago. Then never again, until past few weeks.
Ok, in this case- most likely not a carbon issue on a cold engine.
 

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Mine has a shimyat 1500 rpms, and no code, and I have a ticking noise that I can hear from top of engine and also from inside.
Dealer told me ticking is injector pumps, but it is louder somethimes
And shimy/misfire is only at 1500-2000, in gear or out

Ours has that ticking also.
Sometimes its audible and sometimes not. Sometimes it starts when we get to a red light. Sometimes not.
Very random and only audible at idle.

After looking around etc. It does not appear to come from the engine... Ive come to the conclusion that its related to the High pressure Fuel Pump and the fuel dampener.
I believe the injectors make their own noise.


from a GM tech article---
"fuel pulse dampener may have an audible clicking sound when the engine is idling"
 

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Yep, Same here

Ours has that ticking also.
Sometimes its audible and sometimes not. Sometimes it starts when we get to a red light. Sometimes not.
Very random and only audible at idle.

After looking around etc. It does not appear to come from the engine... Ive come to the conclusion that its related to the High pressure Fuel Pump and the fuel dampener.
I believe the injectors make their own noise.


from a GM tech article---
"fuel pulse dampener may have an audible clicking sound when the engine is idling"
 

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Check codes, and address any that show up
Pull plugs, look at colour. Maybe clean and check gaps
Clean boots on coils when reinstalling.
The trans flush is a good idea too
Check wheel bolt torques .. maybe do that first.

Not likely trans axles or cv joints unless it’s while turning.

If it can’t be repeated, the dealer may be of little help unless they have seen and fixed similar symptoms. At least worth a call.
 

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2015 Terrain V6 3.6L FWD 56k miles
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Mine has a shimyat 1500 rpms, and no code, and I have a ticking noise that I can hear from top of engine and also from inside.
Dealer told me ticking is injector pumps, but it is louder somethimes
And shimy/misfire is only at 1500-2000, in gear or out
Did you ever figure out what was causing your shimmy? I feel the same in my 2015 Terrain 3.6 at 1500-2000 rpm in park or neutral. Changed plugs and coils but the issue remains.
 

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2014 Terrain 60,000 Mi. Vehicles Vibrates For 3-5 Secs. Feels Like I'm Driving Over Rumbles Strips. Has Done This About a Dozen Times in (3) Months. Is Starting to Concern Me. OBDII Codes Checks Showed "No" Active Codes From "Any" System (or) "Any" Stored Codes in Memory. Afraid to Take Vehicle on "Long" Trip. 2014 Terrain 3.6L 6T70 Tansmission AWD. Any Experiences or Advice For Fix and/or Problem Will Be Appreciated.
Did you ever figure out the problem?
 
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