Blogs Car Info Our Show Deals Mechanics Files Vehicle Donation

Jerks in low gear, won't stay in gear

1997 licoln continental, automatic
Around first and second gear, the car hesitates to pull and will ‘jerk’. While it’s doing this the car can be revved unsynchronized as it will try to ‘jerk’ it’s way past around 1st and 2nd gear. Eventually, it smooths out after it’s into 3rd gear and drives normally though after roughly getting through 1st and 2nd. In 1st and 2nd gear, if the gas is let off for a bit before smoothing out… it will often sometimes completely come out of gear, not pulling from any power given. If it does, after popping out of gear the car will not go back into gear, even from a complete stop from ‘park’ then trying to put it back into ‘drive’…no response to power given. However, it goes back into gear just fine, roughly again, if you turn the car completely off and put it back into ‘drive’. Obviously, the car also will hesitate even worse on an incline from a dead stop.

Another note, there is a slight wobble to the crankshaft pulley… though, i feel this issue is completely unrelated to a harmonic balancer noting that the car just pops out of gear and goes back in gear just fine when it is turned back off then back on…but, not unless the car is completely turned off?
What would the obvious culprit be…? Torque converter? Please help me get a DD back on the road. Thanks guys

How many miles and when was the last trans fluid and filter service performed?

the car was meticulously taken care of by the previous owner which was an elder lady. according to paper work, a transmission flush was performed during 9/29/08 @ 119,275 miles. The car currently is clocked at 162,xxx miles according to the odometer.

If there a check engine light? If so then you need to have the codes read.

Have you checked the transmission fluid?

If there’s no check engine light and you’ve checked the fluid and it’s at the right level then you should head yo your best locally owned transmission shop to have it scanned and driven

Check the manual, you might be due for a trans service, but rather than a flush find somebody that can drop the pan and change the filter if applicable.

so, i was taking a closer look tonight in the garage and it seems that the crankshaft pulley isn’t wobbling, but the serpentine belt tensioner may be shot. it is definitely wiggling back and fourth at idle. thinking about it, i have a feeling when putting this shot tensioner under heavy load under first and second, it may no longer sometimes be holding the serpentine belt tensioned down, staying stuck out of position explaining the sudden failure of power being delivered. leaving the car unresponsive at sometimes. i think this might explain the jerking, and complete loss of power under heavy load under first and second until it’s at a higher gear forcing the piece to put more tension onto the belt. Will give it a try and update.

Honestly, that shouldn’t explain it. But if it does I’d be happy to get the follow up report. About the only thing I could think of that might make sense is some irregularity of electrical power from the alternator caused by that.

even if the belt isn’t making full contact at times to the crank pulley from being so loose because of the shot tensioner? i have my hopes up, i’ll be sure to update

i was thinking, in theory…this would also explain why it smoothes out at a higher gear, forcing a lot more tension to the belt

The thing is that the serpentine belt is basically an afterthought of the drivetrain. Nothing about how the engine or transmission works is at all dependent on the serpentine belt functioning well - except for the electrical power supply being delivered by the alternator which is why I mentioned that. And even then a strong and charged battery should smooth out any curves (how is the battery, btw?) But mostly that belt is part of the cart and not the horse. But hey - there are all sort of things I don’t know and don’t think of - so you keep your hopes up and see what comes of it.

so as you said, my bright idea was definitely just ruled out. lol. i had a friend drive my car as i rode in the passenger side until it got to the point that sometimes happens as i explained, where the car acts as if it’s neutral while in drive(no response to the wheels at all from any power given). i cautiously looked under the hood while he left it in drive as it acted like that, and there was no visual difference with anything more than usual compared to when it’s running in drive properly. im going to try to do some research in attempt to trouble shoot more and try to narrow the actual possible cause down…im really stingy about having someone else fix my car for anything. i’d really like the knowledge for myself.

ill keep this updated for future reference when the problem is solved. please feel free to give any knowledgeable advice

what do you guys think about this?

Sorry, I just read the “Jerks in low gear” headline and thought you were writing about Tom and Ray.

What I think about the page on the AX4N is that it about sums it up, though it is generally seen to be more reliable than the AX4S. They are all derivative of the AXOD-E and all of them often have problems up over 100K miles, but mostly IF they don’t get regular service - as in filter and fluid changes.


I would take any information from that website with a grain of salt

I happen to be an ex-Mercedes-Benz mechanic, so I looked at what they had to say about the Benz transmissions. Turns out they don’t know squat. They got several very basic facts wrong, so I assume they don’t even have any hands-on knowledge. I suspect this website just posts information from other sources