[tedo880]

I have a 1998 Ford Contour (automatic) with a strange transmission problem. I have diagnosed it pretty thoroughly so this is what I know.

1. After driving for an extended period at a steady speed, such as on the highway, the car shifts abruptly in response to any required gear change. For example, if I leave the highway, at the stop sign at the end of the ramp the car will start normally in first gear but when it shifts to second it seems to keep the same rpm's and just drops into gear abruptly. This causes a major jolt and typically leaves a little rubber behind.

2. As the car shifts from second to third, it does the same thing. Keeps rpm's up, drops into gear abruptly, and leaves a little more rubber. (The sensation is kind of like when you're in high school and discover "neutral drops" for the first time.) If I can anticipate when it is about to shift and back off the accelerator I can minimize the effect.

3. The local Ford shop says I need a new transmission (without ever looking at the old one) but it seems to me the problem might be more electrical or programming. Here's why...

4. If the car gets in this "bucking" mode, it will continue to do this at each stop sign or stop light for the rest of the trip. But, if I turn off the ignition and re-start, the problem goes away and the car resumes normal shifting and is very smooth.

5. At first I thought the problem might be thermal. That is, maybe the problem goes away once the car cools down after I shut it off. It also seems to act up more when the weather is warm and almost never does this in winter. However, a couple more tests convinced me it wasn't thermal.

6. If I get off the highway and the car exhibits the problem behavior, I can put it in park and then continue driving. The car will continue "bucking" at every stop.

7. But, if the car exhibits the problem and I stop it and *turn it off*, the problem goes away immediately and the car works just great when I re-start it.

8. And, if the car exhibits the problem, I can put it in neutral and turn off the ignition momentarily while still driving. When I re-start the car and continue driving, the problem is gone.

9. Turning the ignition off and then back on fixes the problem every time. (My car behaves as though it's running Windows and needs to be rebooted!)

Any help on this would be greatly appreciated. I'm no mechanic but I understand a little about how to diagnose problems. Hopefully I've provided enough information here. By the way, I spoke with another gentleman who owns a Ford Taurus with the same problem. Weird...

Thanks in advance!

[Ziyad]

Please dont double post. Its not nice.
Welcome to the land of the crappy CD4E, your not so favorite automatic transmission.
Your problem is not electrical.
The PCM is detecting a problem with the transmission, possibly torque converter slip.
Its not bad enough (yet) to activate the check transmission light (aka flashing overdrive light).
By switching the vehicle off, the PCM loses this error.... only engine codes are stored after the ignition is switched off.
The PCM, after detecting the problem, has put the gearshifts into failsafe mode and increased the internal hydraulic line pressure, hence the more aggressive shifts.

The CD4E has a poorly designed valve body that causes low pressure to the torque converter.
The torque converter clutch slips and overheats the transmission, as well as contaminating the fluid.
A full rebuild is probably required at this stage.
During the rebuild, I suggest using a valve body rebuilt using all Sonnax valves, and upgrading the pump plate and pump plate gasket to the latest version.

See the CD4E FAQ at the other Contour site for details.

See also this Sonnax page
See the CD4E section at www.bulkpart.com for some shopping info and surprisingly, good advice.

Ensure that you install as big a transmission cooler that you can fit, to keep things cool.

I did assume your fluid is in good condition.... If you replace the fluid and all is well, you still need to change the valve body to prevent further damage.

[Terry Haines]

'slam shifts' and 'runaway line pressure' is a commonn fault on the CD4E.A TransGo kit will help the line pressure issue and the Sonnax valves can improve it a little.Need a good auto trans shop for this.

[tedo880]

Sorry about the double post -- I'm new to the site and wasn't sure where I should post. Then when I clicked on "View New Posts" I saw the error of my ways.

Thanks for your help!

Ziyad, on Sep 13 2006, 09:12 PM, said:

Please dont double post. Its not nice.
Welcome to the land of the crappy CD4E, your not so favorite automatic transmission.
Your problem is not electrical.
The PCM is detecting a problem with the transmission, possibly torque converter slip.
Its not bad enough (yet) to activate the check transmission light (aka flashing overdrive light).
By switching the vehicle off, the PCM loses this error.... only engine codes are stored after the ignition is switched off.
The PCM, after detecting the problem, has put the gearshifts into failsafe mode and increased the internal hydraulic line pressure, hence the more aggressive shifts.

The CD4E has a poorly designed valve body that causes low pressure to the torque converter.
The torque converter clutch slips and overheats the transmission, as well as contaminating the fluid.
A full rebuild is probably required at this stage.
During the rebuild, I suggest using a valve body rebuilt using all Sonnax valves, and upgrading the pump plate and pump plate gasket to the latest version.

See the CD4E FAQ at the other Contour site for details.

See also this Sonnax page
See the CD4E section at www.bulkpart.com for some shopping info and surprisingly, good advice.

Ensure that you install as big a transmission cooler that you can fit, to keep things cool.

I did assume your fluid is in good condition.... If you replace the fluid and all is well, you still need to change the valve body to prevent further damage.

[ProjectSHO89]

Yep, you've got a wornout valve body. By now, your torque converter is also probably fried. Ziyad covered that pretty well although I can't (at this point) agree that your transmission [i]needs[i] to be rebuilt.

If you're doing the work yourself, about $400 for a TC and a rebuilt VB (with Sonnax valves). If you're having a shop do it, you're just as well to have the CD4E rebuilt due to the amount of labor to pull and reinstall the transmission (or junk/trade the car).

I just went through all this on my wife's 98 138K daily driver. I swapped out the valve body and solenoid pack and installed a 30K cooler back the first week of June. Everything seemed to look pretty good except I had noticed both a drop in fuel economy (she drives 90 miles a day) and that TC lockup seemed to be missing. The harsh shifting reappeared about a month ago on a long distance trip. Finally finished installing a new TC about two weeks ago and now have about 1000 miles on it so far with no faults.

Good job in thoroughly documenting the classic failure symptom of the valve body, BTW. Only thing missing would be a P1744 code (which was probably there but pending so no CEL).

FWIW, AutoZone was quite wortheless in getting the correct torque converter. They ordered the wrong one even after consulting with their vendor. For a 98 with a 2.5, you should have a code letter "C" stamped on the pilot. Aftermarket part numbers should be either "F69" or "FM81" depending on the vendor. The F69 is available special order through O'Reilley's for just over $100 exchange. I didn't have the time to wait several days at that point so was able to locate a transmission supply house in St Louis who would sell to me and ended up with an "FM81" for around $125 exchange. I bought the VB & solenoid pack direct from Axiom for about $250 and $125 respectively back in June.

Quote

9. Turning the ignition off and then back on fixes the problem every time. (My car behaves as though it's running Windows and needs to be rebooted!)

A very accurate comparison. You're resetting the "limp/failsafe mode". It will stay in normal mode until the PCM detects either excessive TC slip or excessive transmission temperatures.

Steve

[Raven981]

Hi. I have this EXACT same thing. Everything that he described about his hard shifting to the 'T' is my transmission. I had the Valve body rebuilt with the Sonnax valves 2years ago, but that did not solve my problem. Is there anything else this could be? Any help would be great. I have been driving with this problem way too long.

Thanks.

Nick

[Terry Haines]

...FWIW the valves alone do not fully cure the overpressure.The contents of the TransGo kit incude springs etc and the need to drill an extra hole in one of the piston plunger parts of the valve body.This reduces the build of hydraulic pressure behind one of the valves...the cause of the 'runaway pressure' and slam shift....One of the reasons this condition stops when you shut down the engine etc is that the pressure buildup behind the valve bleeds off and upon startup the pressures are back to 'normal'....

[Raven981]

Terry Haines, on Oct 31 2006, 11:19 AM, said:

...FWIW the valves alone do not fully cure the overpressure.The contents of the TransGo kit incude springs etc and the need to drill an extra hole in one of the piston plunger parts of the valve body.This reduces the build of hydraulic pressure behind one of the valves...the cause of the 'runaway pressure' and slam shift....One of the reasons this condition stops when you shut down the engine etc is that the pressure buildup behind the valve bleeds off and upon startup the pressures are back to 'normal'....

Oh. I thought, that to fix the problem, you had to do one or the other. (The whole rebuild of the Valve body with the new Sonnax Parts (Sonnax "Pressure Regulartor Valve Kit" PN # 73840-BK and PN # 73840-RK) or the TransGo Kit)
But are you saying that I would need the TransGo kit as well? I would have the smae shop do this as I had to do my Sonnax Valve rebuild. So would I need to tell them about the drilling of the hole, or is that included in the TransGo kit instructions?

Please let me know exactly what more I need to do to get this fixed. You have already helped me out a lot. Thanks very much.

-Nick

[Terry Haines]

The TransGo kit should be used with new valves.I'd check out both the TransGo site & the Sonnax site.

[ProjectSHO89]

Nick,

You likely need a new TC. See my adventure above.

My 98 is still running great (except for that pesky P0442.....)

Steve

[Terry Haines]

...The T/C does not cause the over pressure condition...

[ProjectSHO89]

Terry Haines, on Nov 8 2006, 05:42 AM, said:

...The T/C does not cause the over pressure condition...

That is correct. It is not the cause of the problem, it is collateral damage.

The clutches in the T/C get fried (quickly) due to lack of fluid flow when the valve body fails. The result is no TC lockup after the valve body is repaired.

BTDT, have the dirty t-shirt from replacing the T/C in my own garage.

Steve