I have a 01 MPV just over 200,000KM the trans has been acting a bit strange the past week. it seems when I let off the gas completely to coast around 60KM the tach drops to idle then back up. and you can feel it jerk a bit. sometimes it does it a few times over. the rest of the transmissions functions seem fine. no slipping, nice shifting even under hard acceleration.

I was wondering if it was maybe the throttle position sensor, but not sure.

also thinking of getting a trans flush, the fluid isnt burnt smelling, and still has decent color but I don't know how old it is.

 

It think it is a goood idea to get the transmission servised. It's better to be sure what's in there. Consult the manual so you know what fluid should be used and insist on them using the specified fluid.
If there is a filter in this transmissionit should be changed as well. (For those who wonder: the CD4E transmission in the Ford Contour has no filter.)

If things don't improve after the transmission service we will analyse it further.

 

Ok I had the tranny flushed this morning, and the van seems to be a little better, but still doing the same thing. its doing it between I guess 3 and 4th gear, and only when decelerating. it has a hard time figuring out what gear it wants to stay in.

what is the trans supposed to do when coasting?

 

O.K. I believe this is transmission related. This is my logic:
You are driving along in OD and get off the accelerator in order to slow down. At a certain speed the tranny shifts down a gear or two. Yours has trouble doing this shift and only this particular shift.
How does an automatic tranny shift? A valve gets moved inside the valve body and directs pressure to the clutches involved. Valves can get sticky caused by crud or wear.
I suggest you add "Lucas Oil Transmission Fix". This stuff has friction modifyers in it and it may just get it going smoothly again.

Other things to look at (just in case my logic is wrong): vehicle speed sensor, transmission gear selection sensor. If these had issues it would affect more than just this one particular shift.

I hope the Lucas oil transmission fix does it for you. Please report back.

 

Ok here is the update, so with the flush and now Lucus tranny fix, its still doing the same thing. probably getting worse, I have also noticed when going slow (trying to find a parking spot) the van pulses. the trans seems to still shift up fine, its just down. and its right around 60KM the the most problem is accuring as I only need a little accelerator to keep it at that speed. every time I let off all the way to "coast" it seems to get confused.

I tried disconnecting the battery to see if it was maybe a computer thing, but no change.

any other ideas? is there a separate solenoid for each gear, or what does the trans do when "coasting"?

 

Here is a good description of tranny functions.
Automatic Transmission and Transaxle, Page 2 of 3

Somewhere in the middle it explains how the sensors figure in and at the bottom is a diagram showing the valve body and its components.
That info leads to a process of elimination:
Test circuits, make sure the connectors are clean.
Test senors, clean and re-test if needed.
If that is fruitless I am afraid someone will need to tear into the valve body and check the valves and springs.