Transmission Direct Drive slipping/barely engaging

Hi,

If the fluid is clean and full, I would check the transmission line pressure to see if it is dropping when warm. The cooler could be partially plugged, and I've even seen the filter pick up enough dirt from the pan to cause issues. When cold, dirt would drop to the bottom and allow fluid to flow easily. After driving, the dirt would partially plug the filter lowering pressure.

So, before making any decisions, I would either remove the pan and check to make sure it is clean or check line pressure when the problem exists.

Here are the directions for testing line pressure as well as diagnostic charts:

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2001 Ford Truck Explorer Sport Trac 4WD V6-245 4.0L SOHC VIN K SFI
Line Pressure Test
Vehicle Transmission and Drivetrain Automatic Transmission/Transaxle Testing and Inspection Component Tests and General Diagnostics 5R55E Automatic Transmission Line Pressure Test
LINE PRESSURE TEST
Line Pressure Test

CAUTION: Carry out Line Pressure Test prior to carrying out Stall Speed Test. If line pressure is low at stall, do not carry out Stall Speed Test or further transmission damage will occur. Do not maintain wide open throttle in any gear range for more than five seconds.

NOTE: Certain sensor failures may cause high EPC, FMEM (Failure Mode Effect Management) actions. Be sure that self test and electrical repairs have been carried out, or test results may be incorrect.

This test verifies that the line pressure is within specifications.


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1. Connect pressure gauge to the line pressure tap on the transmission and a tachometer to the engine.
2. Start the engine, increase and maintain 1,000 engine rpm and check line pressures.


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Line Pressure Chart

NOTE: Prior to using this chart, you should check the transmission identification tag. Some early built units will use a different specification.


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3. If line pressure is not within specifications, check EPC pressure.
4. Connect Pressure Gauge to EPC pressure tap.
5. Start the engine, increase and maintain 1,000 engine rpm and check EPC pressure. See the line pressure chart for specification.
6. If EPC pressure is not within specification, GO to PINPOINT TEST E to diagnose EPC operation. If EPC operation is OK, see the line pressure diagnosis chart for line pressure concern causes.


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Let me know if this helps.

Joe

Sorry for the late reply and thank you for the information. I was wondering one other thing I forgot to mention. When I rebuilt the transmission and replaced the clutches and plates that go into the drums they were directional. Of course during rebuild i forgot which way they went and really couldn't find information about it. The clutches for the intermediate band weren't marked with top. Would putting those clutches in the wrong way cause them to go bad quickly?

Thanks again.

Hi,

Yes, it will cause them to fail quicker. They are designed to go in one direction.

Joe

Fluid pressure appeared to be fine. Replaced the transmission oil, found quite a bit of gray sludge on the magnet and light coating on the bottom of the pan. Filter looked somewhat normal, fluid was darker red'ish brown kinda. (Note I've driven this about 1,500 to 3,000 miles since rebuild.)
The transmission when cold works fine, once it heats it forward drive can barely get it moving, reverse is unaffected. Transmission gets really hot though after a little while, touching the transmission cooler compared to the engine radiator the transmission cooler after fiddling with reverse and forward for 10 minutes was like 2-3 times hotter (The pan and cooler were burning hot, couldn't hold my finger on it longer than couple of seconds).
Unfortunately it seems something went wrong when I rebuilt it. The clutches for the direct drive or immediate drum (the center one. Didn't have a top marking, the ones for the reverse drum were marked so I knew those were right, i figured the other center drum ones would need to be going the opposite way, couldn't find information online about it. I'm guessing that was a mistake and i burned up my clutches for direct drive, lol.

I'm probably just going to get a re-manufactured transmission from street smart. I've read that the 5R55E has had quite a bit of updates to the valve body, torque converter, and etc to improve its reliability and shifting and stuff. The re-manufactured transmission comes with all those updates, and I'll probably have a repair shop put it in. Because I do not want to take those flywheel bolts off ever again if i can avoid it, they were the bane of my existence.

Anyways thank you so much Jacobandnickolas for your replies to my questions!

Hi,

You are very welcome. Also, I think you are right with your diagnosis. There shouldn't have been that much material in the pan. Something burned up. Ugh!!! Nothing is ever easy.

Take care of yourself and let us know if we can help in the future.

Joe