4R55E Help... | Page 2 | Ford Explorer Forums - Serious Explorations

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4R55E Help...

As long as the gooves go in those same spots the fluid will flow around to the holes. The main concern I had was with the main valve being stuck partially open (the one that looks like this):

Is the tranny out, or did you just remove the valve body?

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When installing the tranny I have a metal pipe that sits along the top ot the tranny, It is in the shape of a U and is about 17 inches long that connects to a conector near the rear of the tranny and goes up to the bellhousing and then a nother 18 or so inches back down toward the rear of the tranny, where does that end connect or is that the overflow vent hose?

Ok, well I have just taken out my tranny and checked the rebuild I had done on my first rebuild and it all looked fine. Checked everything Brian suggested and all seemed to be fine. I have reinstalled the tranny and it worked great for about 15 miles, had smooth shifts everything was great, UNTIL...

Stoped at a friends house, left the truck running for about 10 minutes, when I left the truck seemed fine but would not get out of 2nd gear (also seems like it is starting in 2nd gear) but will not go above 35 MPH. Works just fine in Reverse and when I start from a stop it works fine but will not shift.

I know the Transmission Range Sensor needs to be replaced, could that have anything to do with it?

Trouble codes it gave me was 645 (No 1st Gear), 646 (No 2nd Gear), 647 (No 3rd Gear) From my ATSG manual the symptom for all of these codes is "Improper gear selection depending on failure mode and manual lever position. Shift errors may also be due to other internal transmission concerns (stuck valves, damaged friction material.)"

Sorry to be so long but I wanted to give all the info I could at this time.

Thanks so much for all the help I have received...

I'm not that knowledgeable but I have a shop manual and am studying for the inevitable rebuild. Pg 07-01A-39 says the following (an expansion of the ATSG info you have):

"Symtoms: SS2: Improper gear selection depending on failure mode and manual lever position.

Failed ON - 2nd gear only.
Failed OFF - 1st, 3rd and fourth gears only.

DTCs: ...645**, 646**, 647**.....

**May also be generated by a non-electrical transmission hardware condition."

The other solenoid failures give different gear failure combinations. You said only 2nd gear was working. I would check the SS2 operation before going to other hardware possibilities.

Hope this helps.


Right, I think it is second gear that is working. The transmission never shifts and it will only go about 35-40 MPH, and that is with the engine at about 3500 RPM's. I did not want to push it anymore.

The fact that it was working and then failed to second gear only may indicate that shift solenoid (SS2) failed on. Brain could give you better input.

If you need any wiring or test info let me know.

Still thinking out loud until the experts check in.......

If a "Failed ON" solenoid 2 (SS2) would cause it to stick in second, I would think that the associated valve sticking or a failed return spring could cause the same condition.

Probably best to do electrical checks first.

Is there a way to test the solenoid either in or out of the valve body?
What kind of electrial checks do I need to do?
Also is there anyway that either the Transmission Range Sensor or the Intermediate Servo Piston Assembly could be causing the problem I am having right now?


We really need an expert here but I'll tell you what the book knows:

Solenoid Service

Removal and Installation

Main control assembly does not need to be removed for solenoid service.

1. Remove fluid pan gasket and filter as described in this section.

Of course they show all the testing with a transmission tester but I assume that you could check the resistance with a high impedance VOM at 22-48 Ohms. (Same for SS1-3 and CCS.) They also pulse the solenoids and listen for a click.

On the Transmission Range Sensor it says:

Symtoms: Harsh engagements and firm shift feel. No 3/4 shift. May downshift to a lower gear. No rpm rev. limiter in park or neutral. DTCs: 634,654,P0707,P0708,P1705

If you want detailed info I can send it email.

Suggest you get a second opinion from Brain. I'd hate to suggest the wrong direction or have you fry a solenoid. :D

Anyone have anymore ideas? I still have the same problem, Transmission acts like it is stuck in 2nd gear. Reverse works just fine but when it is put in D,1,2 it will not get above 35MPH with the engine screaming. I think it is in 2nd because I do not feel it shift from 1st to 2nd. Not sure if it will do 35 in 1st gear. SO I think it is in 2nd. What do you think?

I'm away on vacation at the moment.... but will try and give you a more meaningful response when I get home. Your range of symptoms could be quite a number of things.... things that have run through my mind cover nearly the gamut as your symptoms have changed with your efforts....I have thought: speed sensor, certainly the transmission range sensor (rates high on the list). solenoids, computer inputs.... a place where the Rotunda Transmission sensor would be helpful (in fact I wish I could hook it up to mine and also put a pressure gauge on it... be REALLY helpful....on all fronts.... Do you have ANY engine codes? I'm kinda shooting in the dark here... more in the days to follow....

Thanks, the codes it has given me are listed above in post number 24. They are 645, 646, 647 which are No 1st, 2nd, 3rd gear per the ATSG manual. It also gave me a code for the transmission not being in Park during test and I found that the problem was my Transmission Range Sensor was broken, the little notch that goes in the grove on the shift lever was broken off so when you change the gear shift lever from Park to Drive the Transmission Range Sensor would not move. Those are the only codes I have at this time.

I'm gonna suggest that since yours is broken in any event you go ahead and replace and align the TRS.... will address the rest when I get back. (I HATE the "Gee lets guess and replace" approach, but as you say it is broken, that seems to be something you are going to replace in any event...so why not?)

Yes I already have the TRS and I also have an Intermediate/Overdrive Servo Piston because my old one is damaged by a small tear on the rubber part of the piston. I also have one brand new SS solenoid.

Update, well I have replaced the TRS and now it drives and shifts pretty good. However the OD light is blinking again and it gives me code 647 which is "3rd gear error" But it shifts into and out of 3rd just fine.

Also I put it in low 1st and it will go forward but when I take my foot off the gas its like I have put my foot on the break and it stops with me even touching the break.

Sorry it took so long to post back, I've been pretty busy this holiday season. Glad the TRS seems to have solved the issues other than the 3rd gear code. I'm assuming that the codes were cleared before 647 was stored in the memory again, which makes me wonder if it is an erroneous code or if the sensors are detecting something you can't feel....

Does it shift into 4th OK? The reverse/high clutch comes on when upshifting from 2nd to 3rd, so maybe it is sensing a small (miniscule) delay causing a small engine speed flare or something like that. Can you notice anything going into or out of 3rd (upshifting and downshifting) that might be setting the code?

Yes the codes were reset after I installed the TRS. I cant feel anything when it is shifting up or down throughtout any of the gears. It shifts smooth and when it is supposed to shift.

The only problem that I can feel is when I put the gear shift in Low 1, it will move as long as I have my foot on the gas but it acts like it really dosent want to, as soon as I let off it is like I put the breaks on and comes to a stop.

For whatever reason it seems to take more power to go forward from a stop light and it seems to get a little worse as the transmission gets hotter. Still runs and shifts good, just takes a little more power.

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Did you happen to replace the rear one-way clutch 'sprag' (the one that is in the very rear inside of the case that rides against the rear race) when you did the rebuild? Did you take a good look at the condition of the race (maybe with a long-handled inspection mirror)?

If the rear one-way clutch (sprag) is slipping, it will keep first gear from truely engaging and putting all of the torque to the output shaft. That is engaged in any first gear ("from a stop") no matter what shifter position. It has been a source of failure before (and there are updates from Sonnax for it). See if manual second gear gives you that same feeling (when the rear one-way clutch isn't engaged) of needing more power to get going. I'm assuming that the way you are feeling that it needs more power is by having higher engine RPM's when it is coming off of the line from a stop.

Did you replace that servo piston (just curious)? Was it the OD or the Intermediate servo that had the cut lip (front or back servo)?