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5R55E Pressure Readings & Problems

Transmissiondude

New Member
Joined
August 6, 2014
Messages
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City, State
Houston, TX
Year, Model & Trim Level
2005 Explorer Sport Trac
I have a 2005 Explorer Sport Trac With 4.0L Engine & 5r55E.

I was having problems with the trans intermittently losing reverse when hot, and flaring on the 2-3 shift.

I pulled the trans to rebuild it and find that NOTHING inside the trans is burned, or damaged. I completely rebuilt the transmission to include lip seals, all clutches, all 3 bands, O-rings, gaskets, seals, servos, etc; I even installed a Trans-Go shift correction package. I checked the servo bores in the case very carefully to be sure there was no leakage at the case. There is no noticeable wear in the servo bores.

After rebuild the trans was still doing the same thing. When cold it would work okay, but when hot the trans would feel like it was not wanting to go into reverse and flaring on the 2-3 shift, and also slipping in any gear once it was hot.

I replaced the valve body with a used unit as it was available and I needed to see if I could get it running correctly. Reverse issue seems to be fixed however the trans will now slip in all gears when hot under heavy throttle. Light throttle it will hold all gears just fine. Works perfectly when cold. Not setting any codes & no O/D light flashing.

I hooked up a pressure gauge and have 225 @ idle in Reverse and pressure rises rapidly if you apply the gas. My gauge only goes to 300 and it will peg the gauge in reverse @ 1800+ RPM. In park & neutral I have 75 PSI @ idle. In Drive I have 125 PSI @ idle. Here's the odd part-the pressure WILL NOT rise when in D and I give it gas. It will stay steady at 125 until it shifts to 2nd then it drops to 75, then quickly rises back up again to 125 PSI on the 2-3 shift. However, in NO FORWARD gears will it exceed 125.

I then hooked up a voltmeter to the signal wire to the EPC. With the harness still attached to the transmission I could now see what the voltage to the EPC was doing. In reverse @ idle it was 1.9V pressure @ 225. Give it gas, and voltage drops lower to 1.4V & pressure rises very rapidly to 300+PSI. In drive @ idle voltage is 2.9V pressure @ 125 PSI. If I power brake it (press brakes to keep rear tires from spinning/vehicle moving-pressure STAYS @ 125 PSI but voltage actually increases. In my mind, this is a computer problem because the TCM should be commanding LOWER voltage to the EPC to raise pressure. But this is not happening. I have no voltage drop on acceleration nor does the pressure rise. Of course the vehicle runs normally under light throttle but once you stomp the pedal it will slip in all gears. I believe the problem is the TCM because the computer is not commanding a line pressure increase. Your thoughts?

Any other tests I can try? I'm doing the mod to bypass the trans cooler thermostat tomorrow just to see if it is a temperature related issue. However my tests are showing me that I have a pressure problem so I doubt this latest mod will help.

Lot of reading, but I'm trying to be as thorough as possible.
 



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Welcome to this forum! It sounds like the original valve body had issues, then after you installed a used valve body it corrected some issues but you still have issues. Did you install bonded separator plates or just regular valve body gaskets? Did you use a 1/4" drive In/LB torque wrench on the valve body bolts? Did the used valve body come with an EPC solenoid or did you swap the original EPC solenoid from the first valve body? If so, is this the original EPC solenoid?
 






I did not used a bonded gasket separator plate-I used the standard gaskets from the over-haul kit.

The used valve body had it's own EPC already installed & I changed it as a complete assembly.

Yes, the valve body was torqued in sequence starting in the center out using an inch/lb. torque wrench.

I'm still stuck on why the voltage is RISING when power braking the vehicle in the forward gears. Under acceleration the TCM should be commanding LOWER voltage to the EPC to raise the line pressure and the OPPOSITE is happening. I still think this is an electrical problem.
 






Maybe the wrong gaskets were in the kit which didn't match the separator plates? Take a look at the two PDFs attached to this post from TransGo.
 

Attachments

  • 5R55E_GD[1].pdf
    140.4 KB · Views: 1,302
  • 5R55E-VB[1].pdf
    322.3 KB · Views: 339






I have not watched the voltage drop on this tranny before so I can't help you with that question, but I have fixed several of these buy reflashing the computer or replacing the computer. Also you may want to try cleaning the MAF sensor, the computer uses this help determine load. Good luck.
 






I have a 5R55E trans manual coming soon.. So if I can be any help please let me know..
 






Already have the ATSG manual and it is of very little use when diagnosing problems such as this.

Putting the Superior shift kit thermostat by-pass in today. Thought I would have that done by now but had to order it.
 






Just wanted to follow up and let everyone know I found the solution. I ended up replacing the transmission case-even though I could not see or detect any wear at the servo bores, and even measured them with an inside mic and could not find any wear I wanted to eliminate the case as the source of the problem.

So, new case. Got a valve body from Valve Body Express. Got a remanufactured pump from Transtar. Put the cooler bypass mod from The Superior shift kit in place. Put it all back together and it now runs, shifts, and has all 5 gears & reverse, and TCC lock-up. It shifts extremely firmly like it wants to break the tires loose when it shifts but at least at this point I can sell this POS and NEVER venture down the Ford road again.

To those of you who find yourselves in a situation where you have transmission issues with the 5r55 series of transmissions-I wish you the best of luck. I have over $2000 in parts in this unit and that is with me doing all the labor, and pulling it 3 times total. To anyone reading this that does not own one of these marvels of engineering-DO NOT BUY ONE! Ha ha ha

Peace out!
 






Just wanted to follow up and let everyone know I found the solution. I ended up replacing the transmission case-even though I could not see or detect any wear at the servo bores, and even measured them with an inside mic and could not find any wear I wanted to eliminate the case as the source of the problem.

So, new case. Got a valve body from Valve Body Express. Got a remanufactured pump from Transtar. Put the cooler bypass mod from The Superior shift kit in place. Put it all back together and it now runs, shifts, and has all 5 gears & reverse, and TCC lock-up. It shifts extremely firmly like it wants to break the tires loose when it shifts but at least at this point I can sell this POS and NEVER venture down the Ford road again.

To those of you who find yourselves in a situation where you have transmission issues with the 5r55 series of transmissions-I wish you the best of luck. I have over $2000 in parts in this unit and that is with me doing all the labor, and pulling it 3 times total. To anyone reading this that does not own one of these marvels of engineering-DO NOT BUY ONE! Ha ha ha

Peace out!
Buy one of what ???
 












Correct-I was specifically referring to any Ford vehicle equipped with the 5r55 unit. Ford does make some good transmissions but the 55 is not one of them.

The new 6 speed units seem to be getting good reviews so far. Only time will tell if they can make it to the 200K mile mark though. Don't think they are old enough yet for many of them to have gone that far. They've been out since 2011 if my information is correct.
 






Another, and final update.. I thought about why it was shifting so hard and figured the computer had jacked the line pressure sky-high trying to compensate for the slipping that was occurring before.. So, I got a scanner, went into the computer and deleted the KAM, putting it back to default. Problem solved. No more hard shifts.

Best news? I sold that POS today! It is GONE! Bye-bye! I will withhold tarnishing all Fords because of this experience. I just can't believe that Ford would intentionally build a ticking time bomb like that transmission is and actually sell it to their customers.
I guess all manufacturers are guilty of it in one way or another.. Ford, you got me this time.
 






I have a 2005 Explorer Sport Trac With 4.0L Engine & 5r55E.

I was having problems with the trans intermittently losing reverse when hot, and flaring on the 2-3 shift.

I pulled the trans to rebuild it and find that NOTHING inside the trans is burned, or damaged. I completely rebuilt the transmission to include lip seals, all clutches, all 3 bands, O-rings, gaskets, seals, servos, etc; I even installed a Trans-Go shift correction package. I checked the servo bores in the case very carefully to be sure there was no leakage at the case. There is no noticeable wear in the servo bores.

After rebuild the trans was still doing the same thing. When cold it would work okay, but when hot the trans would feel like it was not wanting to go into reverse and flaring on the 2-3 shift, and also slipping in any gear once it was hot.

I replaced the valve body with a used unit as it was available and I needed to see if I could get it running correctly. Reverse issue seems to be fixed however the trans will now slip in all gears when hot under heavy throttle. Light throttle it will hold all gears just fine. Works perfectly when cold. Not setting any codes & no O/D light flashing.

I hooked up a pressure gauge and have 225 @ idle in Reverse and pressure rises rapidly if you apply the gas. My gauge only goes to 300 and it will peg the gauge in reverse @ 1800+ RPM. In park & neutral I have 75 PSI @ idle. In Drive I have 125 PSI @ idle. Here's the odd part-the pressure WILL NOT rise when in D and I give it gas. It will stay steady at 125 until it shifts to 2nd then it drops to 75, then quickly rises back up again to 125 PSI on the 2-3 shift. However, in NO FORWARD gears will it exceed 125.

I then hooked up a voltmeter to the signal wire to the EPC. With the harness still attached to the transmission I could now see what the voltage to the EPC was doing. In reverse @ idle it was 1.9V pressure @ 225. Give it gas, and voltage drops lower to 1.4V & pressure rises very rapidly to 300+PSI. In drive @ idle voltage is 2.9V pressure @ 125 PSI. If I power brake it (press brakes to keep rear tires from spinning/vehicle moving-pressure STAYS @ 125 PSI but voltage actually increases. In my mind, this is a computer problem because the TCM should be commanding LOWER voltage to the EPC to raise pressure. But this is not happening. I have no voltage drop on acceleration nor does the pressure rise. Of course the vehicle runs normally under light throttle but once you stomp the pedal it will slip in all gears. I believe the problem is the TCM because the computer is not commanding a line pressure increase. Your thoughts?

Any other tests I can try? I'm doing the mod to bypass the trans cooler thermostat tomorrow just to see if it is a temperature related issue. However my tests are showing me that I have a pressure problem so I doubt this latest mod will help.

Lot of reading, but I'm trying to be as thorough as possible.

****Did you find the solution to your problem? We are having the same issues with 2006 Ford Ranger w/4.0L and 5r55e transmission.****
 






Yes, the solution to my problem was replacing the valve body. If you are having problems similar to mine, replace the valve body before you do anything else. Do not buy a used valve body as they all seem to have the same problems. I bought a remanufactured valve body from Valve Body Express (VBX) through Transtar.

You are going to choke when you see what the valve body costs. Good luck with your project.
 






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