01 Overdrive Prblem

[cgraves]

I have a 2001 SEL with 75,000 miles. When driving at highway sppeds 60 - 70 mph, the transmission seems to shift out of overdirve and the RPM go up slightly when not under load. When this occurs there seems to be a slight shudder of the vehicle. The OD lights dones not flash or say on.

Any ideas would be appreciated.

Thanks

[Blue Bowtie]

It probably is not shifting out of overdrive, but it dropping the torque converter lockup clutch. That can be normal if the throttle is fully closed (decel mode). AFAIK, the OD lamp is for OD, not the TCC.

If you want to check this, monitor the engine RPM change when this occurs. Then, depress the button on the end of the gearshift lever to drop OD. Notice the RPM change when that occurs. Compare the two.

[cgraves]

Thanks for the insight, I took it to my local for dealer, after a test drive they thought it was shudder from the torque converter as well. The technician said he normally sees this on rear wheel drive cars and not quite as often on front wheel drive. None the less he suggested that a flush and fluid change may help, since it had been quite some time since it had been changed, the second option was to replace the torque converter.

The flush and fill seems to have helped the problem, the van has been driven about 200 miles since and seems to be doing better.

With regard to the RPM change, when the shudder occurred the change was less than 500 RPM, while turning off OD changed it by about 1,000. Just as you indicated.

In the even that the torque converter needs replacement, are there any other suggestions.

Thanks again for the response.

Clark Graves

[Blue Bowtie]

If you're going to the trouble to replace the torque converter, it would only make economic sense to replace the friction surfaces, seals, and address the commonly troublesome valves in the valve body.

Frankly, unless you plan on keeping the vehicle for a long time, you may just want to roll the dice and continue to use it. Perform the required maintenance, use the correct supplies and materials, and live with it. You could easily spend $2,000 for a transmission repair and new torque converter, and have the engine put a rod through the block 5,000 miles later.

[12Ounce]

Originally Posted by Blue Bowtie

..... the commonly troublesome valves in the valve body.

.
I've recently replaced the seals and gasket (and circlips) on my low-intermediate servo. ('99 3.8 190k miles.) The old piston seal still looked serviceable, but perhaps a bit enlarged and "oval-shaped" in cross-section instead of "round" like the new one.

I may soon be lowering the sub-frame to do some engine front cover work. I think it would make sense, at that time, to do the same simple repair to the overdrive servo. Perhaps I should do more. What valves are "commonly troublesome in the valve body" ... all the little internal check balls, etc?? Are these the ones you refer to as "troublesome"?

What about the accumulator pistons just under the valve body? ... worth changing out the seals?

[Blue Bowtie]

Servicing the transmission in the cradle is a difficult task. Separating the valve body will liberate check balls that may end up anywhere. The problem valves are the pressure regulator abd boost valve (and its bore in the valve body). There are kits avialable to repair this permanently.

https://www.transmichigan.com/catalo...roducts_id=142

[aehegney]

I have a 2000 base model windstar...@ 130K..not really sure because for 2 years that mileage registered half, the speedometer did too, after a brake replacement it stopped. so anyway....often after I have driven for awhile, particularly if its a hilly area, the van will not go into overdrive, i have the transmission flushed and new fluid each year for the past 2 years..this is done at a good reliable place and checked the level of the fluid which is fine. could it be a sensor? I took it to a place to be looked at but of course at that time it was going into overdrive and they said they could no diagnose the problem and hooking it up to a diagnostic machine would not help ethier. does anyone have an idea of what it could be? thanks ann

[C. Cleve]

Hi, You have a POSSIBLE, VSS(vehicle speed sensor)problem, This usually triggers a code, Could be wiring in the VSS circuit or the output speedo gear in the transmission, You need a GOOD tech to take a look at the vehicle and go thru some GOOD diagnosis work...See Ya,....Clay..

[aehegney]

Hi...i have an appt next week at a reputable place for this OD problem, they already hooked it up to diagnostic (did not charge me), never threw a code, this trans guy thinks it is the shift sensor, but i now think the van only will not go into over drive after i have driven at high speeds for a while, like 60/70 mph for at least 1/2 hour, the shifter has been hard to shift though for the past few months though, maybe i should get shift sensor and VSS replaced. anyone have thoughts on this? thanks ann