Acceleration Jolt

Hello all,

Just registered for this forum. I test drove a CX-5 this weekend and it was very nice. After coming back home and reflecting on the ride the one thing I cant stop thinking about was this odd jolt that I felt a couple times.

This was on a 2014 Touring AWD

This seemed to occur from either a crawl or dead stop. Basically I would gently press on the gas and there would be a bit of movement then a bit of a forward jolt and then it would resume acceleration in a smooth fashion. Its hard to describe really and I'm not sure if its normal behavior or not. It feels like I'm applying gas and theres no response for a split second and then its dropping into gear and starts going. I'm coming from an older car with a very slushy automatic. My only guesses are that this is the torque converter lockup or the rear diff engaging in the awd system. It was dry if that helps. Any ideas or does anyone else experience this on a regular basis?

The rest of the transmission was silky smooth, no shiftshock or any other problems when accelerating 5+mph. I was very impressed by the car overall, but if this jolt is a common occurrence its going to be a deal-breaker for me, Ive never experienced this on any other automatics that I've driven.

I may see about test driving another cx5 and just see if the one I was in had a problem. It didnt happen every time, but it was a short test drive.

Ive looked around in the forum and havent found any similar threads, only one about the 6->4 downshift jolts, of which I didnt experience.

First of all, it's most definitely not the rear dif engaging as this will only happen if the front end senses slip (which is hardly ever, unless you're in snow). 99% of the time the AWD CX-5 functions as FWD. Keep in mind that the torque converter only operates up to 5 mph and is only there to assure smooth starts. After that, the wet clutch takes over for greater effieciency. I find this transition most noticible crawling up my driveway and it does feel a bit clunky until you learn to anticipate it. As you acclimate to the transmission, you just learn to put your foot in it as you take off and the transition soon becomes seamless.It's really a great tranny, but it does take some getting used to and a bit more driver involvement than your usual slushbox, but the payoff is at the pump when it averages 30 mpg or better!

I would try a different test drive. It is possible that the transmission learning was not done properly on the CX-5 that you drove. The learning process allows the shifting electronics to adjust to the transmission clutches which should result in a very smooth shifting unit...

Thanks for the replies. I guess I was just accelerating too slowly and the engage point is maybe expecting faster acceleration or more aggressive throttle at launch than I was providing to it causing it to be a bit clunky at the start.

I'll definitely try a different cx5 at some point and see if there is any difference.

GAXIBM said:

I would try a different test drive. It is possible that the transmission learning was not done properly on the CX-5 that you drove. The learning process allows the shifting electronics to adjust to the transmission clutches which should result in a very smooth shifting unit...

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I agree with this. While the CX-5 transmission is unusually direct feeling, I've never felt anything that could be described as a jolt. It feels reassuringly direct, not harsh. Try another test drive.

I have felt this quite a bit in stop and go highway traffic (slow crawl, sudden acceleration, back to a crawl).

I was thinking it had something to do with it shutting down the engine when braking to save gas, (similar to hybrids but without the battery regeneration) but then quickly accelerating again.

tobeychris said:

I have felt this quite a bit in stop and go highway traffic (slow crawl, sudden acceleration, back to a crawl).

I was thinking it had something to do with it shutting down the engine when braking to save gas, (similar to hybrids but without the battery regeneration) but then quickly accelerating again.

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The auto transmission in the CX-5 feels like a manual transmission in gear. If it jolts it's probably due to driver input.

Yes, the "jolt" is so subtle and not sharp but can be felt.

Specifically address comment:
"This seemed to occur from either a crawl or dead stop. Basically I would gently press on the gas and there would be a bit of movement then a bit of a forward jolt and then it would resume acceleration in a smooth fashion. Its hard to describe really and I'm not sure if its normal behavior or not. It feels like I'm applying gas and theres no response for a split second and then its dropping into gear and starts going."

It's normal at idle with foot on brake in Drive (such as waiting for red traffic light), once foot is lifted off brake to hit gas pedal the tranny engages.

CX-SV said:

Yes, the "jolt" is so subtle and not sharp but can be felt.

It's normal at idle with foot on brake in Drive (such as waiting for red traffic light), once foot is lifted off brake to hit gas pedal the tranny engages.

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I've found it helps to either anticipate the light turing green and take my foot off the brake just prior to the change or hesitate slightly after removing my foot and giving it gas. Both methods allow the torque converter to engage at idle speed and begin to move the car on its own.

Thanks again for the replies, it looks like this is indeed normal because of how theyve re-engineered the torque converter. Ive found some articles and read into it and its explaining what I experienced. I guess jolt was a harsh word to use as it didnt physically shake or move me. I could just feel the vibrations as what I assume is that wet-clutch engaging. Its a bit unusual feeling coming from less sophisticated transmissions.

The second is an all-new six-speed automatic transmission. Frustrated with the inefficiency of a traditional torque converter at high speeds, and unwilling to accept the jerkiness of a dual-clutch system at lower speeds, Mazda designed what it feels is the best of both worlds. Its new Skyactiv-Drive automatic uses a torque converter below five mph for a smooth launch, However, at higher speeds the transmission uses a wet, multi-plate clutch just like a dual-clutch transmission does. This was not simple, and it requires a complete redesign of the torque converter – but since it only works at less than five miles per hour, it is smaller than a traditional unit (Mazda says its new transmission is seven percent better in fuel economy than its predecessor and more efficient than a dual-clutch or continuously-variable transmission).

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It is usually more prominent with the transmission new and cold, also during frequent low speed engaging and disengaging the torque converter lock up (e.g. heavy traffic). After the wet clutch pack takes over in 2nd gear, it is silky smooth.

I would guess it is the hill launch assist that you are feeling. This is probably mostly welcome for some drivers on manual transmission vehicles it is on the automatic also.

Per Mazda:
Hill Launch Assist (HLA) This feature helps assist CX-5 drivers when accelerating the vehicle from a stop while on a hill or slope. When the brake pedal is released and the accelerator pedal is pressed, HLA prevents the vehicle from rolling forward or backward. It operates on a downward slope when the shift lever is in the reverse (R) position and on an upward slope when the shift lever is in a position other than the reverse (R) position. The HLA system will hold the vehicle for a maximum of 2.0 seconds while the driver is changing from the brake pedal to the accelerator pedal. HLA is standard on both automatic and manual transmission CX-5 models.

Just as we thought, no jolt.