What could be causing a random uneven or hard shifting?

Question

Hello. I have a 2014 Ford Taurus Limited 3.5L automatic with 130k miles on it. I take it easy when I drive, not racing from a green light to the next red light, easy/light acceleration all the way up to the speed limit. I took possession of the car at around 100k, when I immediately noticed the issue. Whether I just pulled out of the driveway on a typical Houston morning, or I've driven about an hour through traffic, the transmission will shift erratically. It was very random at first. 1-2 and 4-5 are the most common times when it happens. The transmission will either shift noticeably harder, or on some occasions, you feel it shift in two parts, like it starts shifting, pauses for a moment, and then noticeably continues shifting into the next gear (I'm used to a quick, smooth shift). Some times are more noticeable than others, in both instances of shifting. This has also begun happening when upshifting manually, something that previously worked without issue. I have never noticed an issue while downshifting, manually or automatically. And recently, when trying to back out of my driveway, it took almost two seconds to shift into reverse. I've taken it to the dealership and tried to describe this issue (understandably met with a deer-in-the-headlights look). They drove it cold, they drove it hot. Fluid level ok (changed at around 105k miles), linkage ok, no DTC's, updated the calibration, reset the transmission tables. Given back, all shift points in spec, and the dealership wasn't able to reproduce the issue (taken it in twice). It drove like a dream for about 200 miles (spread out over multiple drives on multiple days), and it went from happening randomly to happening every time I get behind the wheel. On two occasions in the past two weeks, I was *very generous* with the gas. She took off with no problem and shifted through each gear near imperceptibly. I've read on a few posts here and there that it could be a sensor or solenoid. Could it be that easy? Should I try a transmission specialist? Any help or advice would be greatly appreciated!

Thumpy · Accepted Answer

Automatic transmissions use a valve body controlled by fluid pressure and clutches to shift. Some of the valve body channels are smaller than the tip of a pencil. As the clutches and gears wear they throw off material which usually gets filtered out. Filters eventually stop working. Just like your engine they occasionally need a fluid and filter change. Usually every 30-50K miles. You should have your transmission serviced. Just do a fluid and filter change. Add a small bottle of Lucas Transmission fix. It'll help with the rough shifts as well. All your doing when you get generous with the gas is make the pump in the transmission raise the fluid pressure and force a shift. Some of these tranny places will try to talk you into a transmission flush. NEVER do this if your car is drivable. Most of the time the "loose junk" clinging to places inside the transmission will break loose and clog those small valve body pathways I was talking about. Then you can't drive at all. In the future if you lose gears or it won't shift at all, a flush is a cheap hail Mary to possibly get a few more miles out of a tranny before rebuild/replacement.

blueray95 · Answer

my car pontiac g8 2009 have the same issue since 2014 until I had an accident last November and had to change the fluid. it does shift way much better than it used to be (still bit hard sometimes) so i think you might need to double check the fluid and the filter and go to a transmission specialist or you could just live with it like me