I recently bought a Grand Marquis w/ 93k miles that initially ran very well.

In the past couple weeks, these "symptoms" emerged.

1) Coasting at 25-30mph, when applying a slight amount of acceleration before an incline, the car lurches over and over like it can't shift into 2nd gear. If I give it just a little more gas, it drops to 2nd and picks up speed with no problem. What gives?

2) Coasting at 45-50mph, in overdrive, over flat terrain with minimal gas to maintain speed; car suddenly lurches (only once and for a moment) which feels like a random hard shift down. I let off the gas for a second and all is normal (until the next time). What is this?

I first suspected "gear hunting" but the randomness of this lurching problem is making me worry. Also, transmission fluid appears clean without burnt smell.

Any advice would be greatly appreciated.

 

Sounds like what you suspect as gear search...If I intend on driving around town without getting over 50mph I click the overdrive OFF...It seems much easier to drive without the trans trying to find a gear to stay in..Have you done a complete trans service..Fluid,filter and gasket??? I have a 2001 Grand Marquis LSE(floor shift model)..Try driving with the od off...

 

Thanks Paul,

I do keep the o/d off as much as possible, unless going on the highway, which does help to avoid the lurching. I haven't had a trans flush yet but am trying to determine if I need one. The trans fluid is pink and without odor so I'm not sure what else to look for.

Since my post the other day, I drove 200 miles through mountainous Vermont with very few noticeable "gear searches". Than earlier today, with o/d off, coasting at about 30 around town, I noticed on two separate occasions the strange single lurch that feels like a hard shift down. Being that both times I was maintaining a stable speed with a steady amount of gas on flat terrain, I still can't figure that one out. The only other variable was that it was snowing and the roads were slick.

I can easily deal with vehicle quirks; I just moved from a small island in the Caribbean where every vehicle has endless issues. I'm just worried that the transmission will drop out and leave me screwed.

-Kevin Parker

 

I ALWAYS change out my fluids on any car I get..Sometimes previous owners will just swap out oils and not change the filter just so the fluid looks good,Just a thought...
Does your car have the stock rims on it? sometimes people put oversized rims on and it screws with the gear ratio...