5r55W/S/N Solenoid pack repair instead of replace

[Hawkeye61]

Just thought I'd share my solenoid pack experience in hopes it may help others.

My 2002 Explorer XLT suddenly had harsh shift going into reverse and into 3rd. The O/D light was flashing as well. I knew the problem was in the solenoid pack after doing some research so I tore into it.
After removing the solenoid pack from the vehicle I did a bench test on the pack using this video from youtube ... https://www.youtube.com/watch?v=3trapVvjJMM as a guide and found that the PCC (Pressure control solenoid C) was not working.
Since I am a tight wad I decided to see if I could repair the pack instead of replacing it.
The white arrows in the photo below shows some locations for some plastic caps that I had to grind off and the red arrows show locations for tabs that needed to be released.



Once I had them removed and released I was able to remove the plastic covers (2 of them) that cover the electrical routing of the solenoid pack.



In the upper left corner I noticed a break connecting one of the terminals to Solenoid C. Ah ha!



After soldering up the break, touching up some other weak looking spots and cleaning the pack, I super-glued the plastic covers back on, reinstalled the pack, put in a new filter and fluid and Bingo! Working like a charm once again!!

 

[2000StreetRod]

clever repair!

I wonder what was the reason for the failed trace. The solenoid packs are supposedly sealed so corrosion from the ATF shouldn't have happened. I suspect it was defective trace during manufacturing. The current flow thru the reduced conductive volume would have increased the temperature making the trace into a "very slow blow" fuse.

I think you have added another argument for me not to purchase a rebuilt solenoid pack since I doubt the rebuilding process includes inspection of the circuit traces. I was already concerned about wear of the bores from the constant movement of the modulated solenoids.

 

[imp]

Just thought I'd share my solenoid pack experience in hopes it may help others.

My 2002 Explorer XLT suddenly had harsh shift going into reverse and into 3rd. The O/D light was flashing as well. I knew the problem was in the solenoid pack after doing some research so I tore into it.
After removing the solenoid pack from the vehicle I did a bench test on the pack using this video from youtube ... https://www.youtube.com/watch?v=3trapVvjJMM as a guide and found that the PCC (Pressure control solenoid C) was not working.
Since I am a tight wad I decided to see if I could repair the pack instead of replacing it.
The white arrows in the photo below shows some locations for some plastic caps that I had to grind off and the red arrows show locations for tabs that needed to be released.



Once I had them removed and released I was able to remove the plastic covers (2 of them) that cover the electrical routing of the solenoid pack.



In the upper left corner I noticed a break connecting one of the terminals to Solenoid C. Ah ha!



After soldering up the break, touching up some other weak looking spots and cleaning the pack, I super-glued the plastic covers back on, reinstalled the pack, put in a new filter and fluid and Bingo! Working like a charm once again!!

Appreciate fully your presentation. But, for most of us, the depth of your own understanding and ability to work out problems, is beyond us.

That said, I had a non-functioning TCC, and replaced the solenoid module, which fixed it. The guide bushing for the TCC solenoid's plunger had gone south, crumbled into little bits (bronze).

Anyway, I believe the TCC solenoid in Gen. 3s is the overworked item. Ford, in it's encompassing wisdom, chose to release the TCC EVERY time the gas pedal was released. Many drivers press gas, release, press, release, ad infinitum, beating the hell out of the TCC. imp

 

[2000StreetRod]

TCC control

. . . That said, I had a non-functioning TCC, and replaced the solenoid module, which fixed it. The guide bushing for the TCC solenoid's plunger had gone south, crumbled into little bits (bronze).

Anyway, I believe the TCC solenoid in Gen. 3s is the overworked item. Ford, in it's encompassing wisdom, chose to release the TCC EVERY time the gas pedal was released. Many drivers press gas, release, press, release, ad infinitum, beating the hell out of the TCC. imp

Very interesting. For the 5R55E I think the TCC solenoid is variable force style (VFS) just like the EPC solenoid and is frequently adjusted by the PCM which increases bore wear. For the 5R55S/W the TCC solenoid is a pulse width modulating type and PCA, PCB and PCC are VFS solenoids. On my 2000 Sport there is a calibration constant to vary how much the engine speed can drop before the PCM unlocks the torque converter. There probably is a similar calibration constant for the 3rd generation vehicles.

It seems odd that Ford would needlessly unlock the torque converter since that would impact fuel economy. I wonder if it is related to shift anticipation. Shifting under load with the torque converter locked increases the failure rate of the clutches and bands. The PCM implements torque reduction during shifts to extend the life of the transmission.

 

[Hawkeye61]

I wonder what was the reason for the failed trace. The solenoid packs are supposedly sealed so corrosion from the ATF shouldn't have happened. I suspect it was defective trace during manufacturing. The current flow thru the reduced conductive volume would have increased the temperature making the trace into a "very slow blow" fuse.

I think you have added another argument for me not to purchase a rebuilt solenoid pack since I doubt the rebuilding process includes inspection of the circuit traces. I was already concerned about wear of the bores from the constant movement of the modulated solenoids.

You bring up a good point. There was just one break in the traces on mine (green arrow) but solenoids A, B and C all had weak (thin) places on them that I touched up also. (160,000 miles)



I certainly hope the new traces are a part of the rebuild but not sure if they are or not.

 

[imp]

Very interesting. For the 5R55E I think the TCC solenoid is variable force style (VFS) just like the EPC solenoid and is frequently adjusted by the PCM which increases bore wear. For the 5R55S/W the TCC solenoid is a pulse width modulating type and PCA, PCB and PCC are VFS solenoids. On my 2000 Sport there is a calibration constant to vary how much the engine speed can drop before the PCM unlocks the torque converter. There probably is a similar calibration constant for the 3rd generation vehicles.

It seems odd that Ford would needlessly unlock the torque converter since that would impact fuel economy. I wonder if it is related to shift anticipation. Shifting under load with the torque converter locked increases the failure rate of the clutches and bands. The PCM implements torque reduction during shifts to extend the life of the transmission.

You are more well-versed in the application of converter clutch use, more so than I. My knowledge is "gut-developed". The "brainchilds" working within the manufacturer's caves are impossible to second-guess.

The problem I stated regarding excess TCC operation I've observed in my '04. Without corroborating hard data, I'm estimating that, given cruise on a level highway, ~ 55 mph, a release of throttle pedal position of 25% results in TCC release. However, GRADUAL pedal increase back up locks the TCC before rpm go higher than lock-up rpm, in other words, minimal clutch slip.

I've read the manuals describing pulse width modulating solenoids, and am not understanding of your reference to "VFS". I HAVE observed the TCC lock-up to vary in rate, probably a programmer's attempt to "mask" the event from "feel" in the cab.

AOD transmissions almost had the better idea, no TC use in 3rd. and 4th. gears, but disallowed downshift to third along with TCC unlock. The best of all worlds is yet to be found... imp

 

[2000StreetRod]

VFS explanation

According to Borg Warner:

"Variable force solenoids (VFS) control pressure proportionally or inversely proportionally to a current driven input signal from the vehicle’s powertrain computer. Typically, low-flow VFSs are used as signal level devices for transmission line pressure control or application of clutches. High-flow VFSs control line pressure directly or are used for direct shift clutch control."

"PWM solenoids, available in High-flow and Low-flow variations, provide pressure output proportionally or inversely proportionally to input voltage pulse width. The low-flow solenoid provides signal level control, typically for torque converter control. The high-flow solenoid is used in line pressure or direct clutch control applications."

In my opinion, a line pressure sensor should have been incorporated into the 5R series to use as a reference for the various sensors.

I read a post by a shop that repairs the 5R55S/W stating that the TCC solenoid needs replacement more than any other part in the transmission.

 

[imp]

I read a post by a shop that repairs the 5R55S/W stating that the TCC solenoid needs replacement more than any other part in the transmission.

Thanks for the info. IMO, the TCC sol. as you say, is overworked. In mine, the bronze bushing in which the plunger rides, crumbled into bits, much of which was piled up on top of the valve body. I cleaned everything away that I could, in stalled a new sol. module, Bosch, in it's original box, installed an in-line filter.

Been about 50K now, working well. I would install a manual TCC sol. switch, but would hate ignoring the flashing O/D light whenever incorrect shaft speeds detected. imp