Mild "trailer-hitching" sensation in Drive 6

[dave245]

I have noticed a mild "trailer-hitching" sensation while cruising in 6th gear at about 80 km/h (50 mph). The effect goes away if you switch to manual mode (still in 6th gear) - torque converter appears to unlock and RPM increases by about 250 rpm.

Has anyone else noticed this? You have to be on a smooth, flat road to notice it.

I have a GT AWD...

Dave

[dave245]

I found a GM TSB that describes a similar condition as "Chuggle" or "Fishbite" on light-load cruise at highway speeds. The issue was related to a defective Throttle Position Sensor (TPS). When tested separately, if it exhibited a sharp voltage drop within its normal range of motion (ie. not a smooth voltage variation with throttle angle), it could cause symptoms that feel like they are related to transmission torque converter lockup. The GM Tech2 diagnostic tool would not normally identify such transient, short duration events so specific sensor testing was required. The ECM would not set any TPS codes either.

I'll mention this to my dealer when I go in for my first oil change in September.

My current work-around is to shift to manual mode in 6th gear at 80 km/h (50 mph). This unlocks the torque converter and the symptoms are dramatically reduced. It feels like engine misfire but the MIL does not flash.

Dave

[DashingMax]

Well, I'm glad I didn't get the tow package.
Hopefully Mazda can quickly resolve this issue.

[Craig-CX9]

I think I have htis problem on my 2007 AWD GT. When the car is in 6th gear and under light load it feels as it slips... The dealer cannot repeat the condition. Any thoughts?

Craig

[4wardmotion]

I think I have htis problem on my 2007 AWD GT. When the car is in 6th gear and under light load it feels as it slips... The dealer cannot repeat the condition. Any thoughts?

Craig

I've experienced something similar for the past year; what I would describe as a hesitation / miss-fire / hiccup....? It will usually occur as I start to accend a hill. It usually just occurs once, but could happen several times while on a long drive. Today, for the first time ever, it happened again while accending a hill, but instead of the single occurance, it kept happening for about 60 seconds. Unfortunately, I was in somewhat heavy traffic going about 70 MPH, so I didn't have an opportunity to do any investigating.

I called Mazda customer relations just to have a record of it because I am 300 miles shy of the end of my powertrain warranty, I don't have the ability to drop it off at a dealer before the end of the week, and I'll be putting over 500 miles on my car over the next 2 days, so I will be over 60K by Wednesday evening.

I never get any kind of indication/CEL that anything is wrong, so unless the Mazda rep takes it for a long ride and it happens to them, I have a feeling I may be wasting my time bringing it in for service. I assume if I had received a tank of bad gas, that the issue would occur for a longer period. This happened today when I had a 1/2 tank of gas - and I always fill it up when I go to the gas station.

It's just frustrating that I may not ever figure out why it's happening.

[Craig-CX9]

Has anyone resolved this probelm?

Craig

[Craig-CX9]

Has anyone had their torque converter changed as a result of this problem? My dealer has had my car in and out (while there for oil changes, etc...) and did feel the sensation once. They changed the rear diff fluid and it went away..for them. I still have the problem but wasn't able to reproduce it for them when I took it for a ride with the tech. Any help would be much appreciated!

Thank you,
Craig

[Craig-CX9]

UPDATE:
I called Mazda Corp and discussed this problem with them. They already had the details from my dealer who had already opened the file. :) I called the dealer and dropped off the car AGAIN for them to diagnose the problem since it was still happening. I got a call from service this afternoon and apparently the car FINALLY acted up..and this tme the right person was driving..a factory rep! A whole new rear differential and PTO are on order and should be installed by the end of the week. It was explained to me that the shuddering sensation is coming from the PTO (controls power split from front to AWD) improperly engaging/proportioning power to the wheels for traction control.

Stay tuned!

Craig

[Craig-CX9]

NEW UPDATE:

I picked up the car after they installed the new PTO (transfer case) and rear differential. I drove it for a few days and wouldn't you know it.. it started acting up AGAIN!! The shuddering sensation seemed to be less intense initially, but after a few days it was back to full intensity. I called the dealership and informed them that I was going to be dropping the car off again and the service manager was very understanding. I got a loaner and off I went.
A few days went by and then I got the call that I was hoping for.. they fixed my car. The same service tech had been driving my car and was pretty good at reproducing the problem. Instead of relying on the hand-held OBDII scanner, they hooked the car up to a laptop that could monitor the OBDII real-time. Now they could see what the car wasn't reporting in its OBD log.. A CYLINDER MISFIRE! All this time the fairly intense shuddering wasn't coming from the transmission drivetrain, but from a single cylinder misfire. The computer indicated which cylinder and upon inspection they found evidence to support that claim... I think there was a hairline crack in sparkplug. They changed the plugs and could not reproduce the problem! I have to admit that I was skeptical at first, but it hasn't happend to me since I picked up the car (over a week now). So, I got a new PTO, rear diff, and a set of plugs...
Hope this helps others who have the same shuddering sensation from "drivetrain".

Craig

[4wardmotion]

I had the exact issue as Craig-CX9 - it started about a year ago with around 48K miles on the odometer. It seemed like a fuel delivery / ignition issue to me, and in hind-sight, I should have gone with my gut and replaced the spark plugs back then. After putting up with this for almost a year, 3 trips to the dealership where they could never reproduce the issue, I happened to read Craig's latest posts and decided to replace my plugs about 3 weeks ago.

As of today, I've put an additional 1300+ miles on the car with not 1 incident of the issue re-occurring. I just wish I had replaced the plugs last Fall to save myself all the time and aggravation. I replaced the OEM Motorcraft Platinum plugs with Autolite Iridium plugs. I would have rather used an NGK plug, but there were none available locally and I was anxious to see if the plugs would finally resolve this issue. I've driven well over a million miles (in ~ 18 different vehicles) and I don't ever recall having a spark plug issue before.....only replaced them as part of routine / preventive maintenance. I guess there's a first for everything.

I big THANKS to Craig-CX9 for posting his experience ---- and his local Mazda service team for being diligent and getting the issue resolved for him!!
I'll bet we're not the only two to have the issue with the plugs.

[kornholio]

To the person that replaced the spark plugs did you do this yourself. How did you get the engine cover off. Also how did you get to the back plugs? Any info would be greatly appreciated.

[nfn2000]

I just posted my question here. The problem you mentioned sounds like mine. Here is my summary. Are you experiencing something like this:
Jerky transmission in same gear
I feel a thumping jerk when im within a same gear but take off my foot of the gas and push the gas again. Im not abusing the gas pedal but actually do it very slowly. But whenever I engage the gas again, I feel a thumping jerk as if the engine power was disconnected from the wheels when my foot was off the accelerator and gets re-engaged when I gently push the accelerator. But this re-engaging is not smooth but kind of clunky/jerky. Very subtle but my car is just 3 months old. Its similar to jerky transmissions which are rough shifting BETWEEN gears. But mine does it when within the same gear. Is there some known issue similar to this? Thanks!
Its 2010 FWD Sport CX-9. No tow package.