25 Tacoma Hybrid(iFORCEMAX) Vibration at low speeds.

[ramcoma]

lately I have noticed a very slight vibration when taking off from a dead stop and turning at low speed. It almost feels like going over a slight rough patch on the road. I could almost describe it like the feeling when a clutch is juuuuust starting to slip/fail in a manual vehicle for when you don’t have quite enough power to push through the shift. its very transient last 2 seconds, and disappear as i accelerate. The issue mainly happens when the truck is cold or when its been sitting for a while and disappears when the truck has been driven a few miles after several stop and go cycles. I have run my own test, and when put the gear lever in manual mode, the problem doesn't happen. I have taken it to the dealer and they checked it and told me they ran health check and no update have to be done or set any DTC's, and hybrid vehicles may shift different when eigne stop running and start. They called it a normal behavior, and said there is not problem with the transmission. Does anyone else have such experience with their hybrids?? I am thinking may be my hybrid motor is failing??

Sponsored

 

[grwil67]

Have seen on these forums inssues with the rear drives shaft causing this and it was same model as yours. So a search or maybe someone will chime in.

 

[grwil67]

Yepn search driveline and you will see several comments on the rear drive shaft.

 

[ramcoma]

I did read through those, but my issue happens from a dead stop, not while driving. What’s crazy is the problem disappears when in manual mode and also once the truck has been driven after several stop and go cycles. It almost seems like the cultch in the hybrid motor is slipping.

 

[grwil67]

OK, I see and just another Sr. moment.
Your thinking seems spot on as something in hybrid seems off.
How many miles?
And you are saying this happens only while in hybrid (electric mode)?

 

[redlimitediforcemax]

I have the same symptom as you and from what i've discovered I believe it's because the transmission fluid has settled at the bottom of the transmission oil pan after sitting for a while. As you start driving, it starts to circulate throughout the transmission, lubricating the gears and parts inside. Like you, I put it in sport mode or I keep the shifter on S2 until I get pass that first initial first second gear change. Its all good after that. I also noticed if I switch it to drive and hold the brake for 10-15secs before I take off, it doesn't happen. Its been like this since I first pulled out of the dealership making a left turn.

 

[grwil67]

I have the same symptom as you and from what i've discovered I believe it's because the transmission fluid has settled at the bottom of the transmission oil pan after sitting for a while. As you start driving, it starts to circulate throughout the transmission, lubricating the gears and parts inside. Like you, I put it in sport mode or I keep the shifter on S2 until I get pass that first initial first second gear change. Its all good after that. I also noticed if I switch it to drive and hold the brake for 10-15secs before I take off, it doesn't happen. Its been like this since I first pulled out of the dealership making a left turn.

Sounds like you have found a work around.
So, when you get in and take off engine is not running as in hybrid mode, then all of a sudden with 0 run time transmission is trying to take off? Is this correct?

 

[redlimitediforcemax]

Sounds like you have found a work around.
So, when you get in and take off engine is not running as in hybrid mode, then all of a sudden with 0 run time transmission is trying to take off? Is this correct?

It happens mostly after the transition from hybrid to gas mode. Only in eco or normal modes. Can occur in gas mode only as well. The transmission seems to skip 2nd gear and slams into 3rd gear. It doesn't help that the gearing is short for 2nd gear but really tall for 3rd so its even more pronounced when it happens. Feels kind of like a grinding, lugging sensation. It could also be described as torque converter shudder. When rpms dip below 1300rpm, is where it tends to do it the most. Sport mode has different shift logic so it doesn't rush that 2nd to 3rd gear. It holds gears longer so 2nd revs up to 3000rpm before shifting and is why you never feel the vibration. Hopefully that makes some sense.

 

[grwil67]

Was wondering is engine was completely off as in no transmission fluid movement when in hybrid mode? As that would be horrible on any transmission to instantly go.
Seems like engine needs to be @ idle and ready.

 

[ramcoma]

OK, I see and just another Sr. moment.
Your thinking seems spot on as something in hybrid seems off.
How many miles?
And you are saying this happens only while in hybrid (electric mode)?

yes it seems to happen only when in hybrid mode, otherwise it doesn't. It also goes away once it goes through several stop and go cycles. It almost feels like it grunts/shutters through the gear and happens under light throttle. Funny part is, this never happened for the first 3 months of ownership, started happening at about 3000 miles, my truck only has 6000 miles on it as we speak.

 

[ramcoma]

I have the same symptom as you and from what i've discovered I believe it's because the transmission fluid has settled at the bottom of the transmission oil pan after sitting for a while. As you start driving, it starts to circulate throughout the transmission, lubricating the gears and parts inside. Like you, I put it in sport mode or I keep the shifter on S2 until I get pass that first initial first second gear change. Its all good after that. I also noticed if I switch it to drive and hold the brake for 10-15secs before I take off, it doesn't happen. Its been like this since I first pulled out of the dealership making a left turn.

I am assuming this a common behavior for us hybrid owners, but not sure it is a "NORMAL" behavior. Are you on factory rims/tires?.. My current setup is 285/70/17 with Falken Wild peak AT4W which is considerably heavier than the stock setup. I was thinking it might be the heavier tire that is putting extra load on the hybrid motor/transmission during the initial take off? FYI i do warmup the truck every morning for 10 minutes before driving, I never just turn on and go.

 

[redlimitediforcemax]

I am assuming this a common behavior for us hybrid owners, but not sure it is a "NORMAL" behavior. Are you on factory rims/tires?.. My current setup is 285/70/17 with Falken Wild peak AT4W which is considerably heavier than the stock setup. I was thinking it might be the heavier tire that is putting extra load on the hybrid motor/transmission during the initial take off? FYI i do warmup the truck every morning for 10 minutes before driving, I never just turn on and go.

I am on stock size tires. Regular SL passenger tires. It happened when new on the cheap general grabbers that came with the truck so I don't believe its because your tires. It doesn't help for sure though lol but im sure its also the transmission.​

 

[ramcoma]

I am on stock size tires. Regular SL passenger tires. It happened when new on the cheap general grabbers that came with the truck so I don't believe its because your tires. It doesn't help for sure though lol but im sure its also the transmission.​

Thats good to know...have you tried taking yours in to the dealer???

 

[redlimitediforcemax]

Thats good to know...have you tried taking yours in to the dealer???

Not yet. It's been a year and it hasn't really changed so I have not bothered to do so. Plus I've been seeing other owners report the same thing. Until something breaks, I won't have a reason to have toyota check it and tell me it's normal.

 

[redlimitediforcemax]

Just a quick update.

I've been getting my truck tuned by @CAMTuning, trying to iron out the poor shifting calibration toyota graciously gave us on the hybrid drivetrain. It's coming along really well. I had CAMtuning adjust the shift points of the transmission and it has pretty much eliminated most of all the annoying vibrations I experience with the Hybrid drivetrain. That 1-3 gear hard shift during cold start has been greatly reduced to a hiccup. The 36-44mph vibration has been greatly reduced (note: on Premium gas, after several tanks of gas, it was completely eliminated leading me to believe it's a combination of fuel and spark). No more lugging and vibration in high gear in 35mph-55mph zones where the transmission tends to lock into 6th/7th and sometimes 8th gear. The MPG has stayed the same if not slightly better in all situations with the truck in the right gears and rpm. I have my transmission tuned to be less aggressive than Sport mode, but shift slightly higher than OEM eco/normal shift points. Now every gear shift lands above the 1500 rpm range where on OEM calibration, anywhere below that would cause lugging and vibration. At highway speeds, 8th gear is engaged above 62 mph (shift lands on roughly 1500 rpms) and kicks down to 7th more immediate when you apply throttle. before that, it would shift to and lock on 8th gear at 55 mph (speeds dropped to 50 mph and it was still locked!) at less than 1500rpms, it caused the drivetrain lug and vibrate badly especially going up any hill. Overall the truck now drives about 90% vibration free in all driving situations.

I spent a lot of time testing every gear and which rpms caused lugging and vibrations. gears 1-2 don't have much issue. 3rd because it's geared so tall, does vibrate when it shifts from 2nd to 3rd. They are not matched well at all and the RPMs would drop off dramatically from gear to gear (TOYOTA ARE YOU LISTENING?). I countered this with having 2nd gear shift a little higher in the rev band so when it shifts to 3rd it's above 1500rpms, vibration gone. 4-5 gears have little issues lugging at all. 6th gear slightly does it at lower than 1500 rpms which is now fixed by the higher shift point from 5th to 6th. But the biggest culprit is 7th and 8th gears (overdrive gears). the factory calibration likes to lock these gears in even at lower than ideal rpm speeds = a bunch of lugging and vibration. With the tune, it never touches 7th and 8th gears in the 35-50 mph range. This still maintains decent mpg numbers and the revs are lower than sport mode and slightly higher than eco/normal.

Hope this information helps the hybrid owners experiencing drivetrain vibes.

Sponsored