96 Windstar, Power Train Roughness Cruising

Just drove home a 96 Windstar purchased Saturday morning. 97,000 miles, 3.8L engine, one owner, serviced at local dealer from who I bought it. Seems in real nice shape.

Driving it home I noticed some roughness in the powertrain while cruising at 58mph, and and 65mph. Pretty much a bit of noise and vibration. (certainly does not seem to be from front end or tires) It seems as if the transmission is fluctuating as to whether to be in OD, or not. I notice the RPMs will suddenly go up 200 or 300 RPM, and then quickly drop back. Sometimes you can feel the transmission change. Don't know where to start working on improving this.

Dana

i had the same problem with my 95, these vehicles are bad about having torque converter shudder around the lockup stage, i changed the fluid and filter and added a bottle of lubegard red and that did the trick. also make sure you use mercon v transmission fluid, hope this helps you

It is something to consider. Since I bought this from a small town dealer who sold the car orginally and did all the maintenance on it I asked them to pull the maintenance records and send them to me. That I hope will point me to what I need to concentrate on maintenance-wise.

Did you do a complete fluid change? Flush? Seems like every shop I visit these days is trying to sell me on an auto-transmission flush. About as often as someone tries to sell me an extended warranty on electronics.

I get the impression this is not an uncommon problem with many cars. Couldn't say how many times I have read test drives that mention the transmission sort of searching for gear while at cruising speed. Don't know if it is worse at some speeds that others. My impression was it was the worst at 58mph, and not as noticeable at 65.

Dana

i had the same problem with my 95, these vehicles are bad about having torque converter shudder around the lockup stage, i changed the fluid and filter and added a bottle of lubegard red and that did the trick. also make sure you use mercon v transmission fluid, hope this helps you

The transmission fluid needs to be changed AT LEAST every 30K miles.
This would be a complete fluid exchange, no cleaners, just new Mercon V fluid.
This is super important on modern automatic transmissions.
Older cars did not need this frequent service, but newer ones do.
The owner's manual will say 30K miles for normal service and 21K miles for severe service.
FORD just this past year issued a TSB stating that Mercon V is now back specified for all years.
This TSB supersedes former TSB's that stated NOT to use Mercon V in Mercon vehicles.
Mobil 1 has a Mercon V that is good, and readily available.
Mercon V was introduced specifically to address transmission shudder.
I would try the Mercon V fluid without any additive first.

If you have the filter changed, a good mechanic will look at the deposits in the pan and be able to tell if there is a problem developing.
Some fine "dust" is normal.
I have pictures posted that show the fluid / filter change on my '96, so you can see what is involved and the normal fine film of dirt that will be present in a healthy transmission.

I appreciate the additional information. Certainly it makes sense to start there. The behavior sure seems as if it would result in increased stress on the transmission.

Are there additional probable causes for this? Speed sensor, etc.

Dana

There are other things that can cause this...but the fluid is the first place I would look...it is a common cause.....and it is a routine maintenance item.
If you still have some shudder with the new fluid, you could try the additive that has been mentioned.
The transmision holds 12 and 1/4 quarts of fluid.
I run about 14-15 quarts through to do a good flush.
If you don't want to do it yourself (dropping the pan is real messy), you could have it done at a shop.
The shop will use a exchange machine, that adds new fluid as the old comes out.
You can also bring your own fluid, so that you can have the fluid you want in there.

There are people who drop the pan and change the 5-6 quarts in the pan....and install a drain plug on the pan.....and change the fluid in the pan on a more frequent basis than the 30K mile interval.
That may work on a ongoing basis...but at this point, you need a complete fluid exchange.
I do the complete fluid exchange once a year.

The speed sensor is not an expensive part, but it is a real pain to change.
So I would hold off on that for now, and it should give a code and light the CEL if it fails bad enough.

wiswind,

I could do it myself though I am not the handiest of folks, but I'll take it to a shop. This vehicle is going to be primarily used in the city with an occasional trip. Definitely want to see if fluid replacement will do the trick. It was quite annoying on the drive back from picking up the Windstar. On the other hand my wife probably wouldn't have even noticed it. That is why I insisted on driving it back so I could spend some extended time listening and feeling it out.

Dana