4R55E Help...

[Barcuss]

No, I did not replace anything at the rear of the tranny. I did not have a mirror to look and see the condition of the rear race.

I just tried in low 1 and low 2 and when it was in low 2 it seemed to require more RPM's to get going.

I have not replaced the servo piston yet and I am not sure which one has the tear.

 

[Glacier991]

you mean manual 1 and manual 2? Manual 2 would. The excessive engine braking that you seems to describe... wonder if we have a weak release circuit? (thinking aloud for Brain to ponder). That could cause a drag on a band, or clutch. OR a cross leak?

 

[Glacier991]

Let's stay with the TRS a min. How did you adjust it? I'm going back to some alignment issues there.... cannot say why...I really have scant knowledge on this subject.

Also have you carefully checked the wiring loom to the transmission? Might it have gotten crushed or damaged in the remove/install?

 

[Barcuss]

I do not have the adjusting tool for the TRS so I did the best I could. Is there a way to adjust the TRS with out the alignment tool?

I have not checked the wiring going to the transmission but I will as soon as I have enough day light.

 

[Barcuss]

Bump

 

[Brain]

I don't have one from a 4R55E, but the one I have from a 5R55E (which I figure would be very much the same - part #F7LP-7F293-AA in the black plastic casing right in front of the electrical connector on the outside). This one has a marking of a CL (centerline) right above "NEUTRAL" on the outside of the case right above the shaft between the two mounting bolts. Right below that is a straight line. The part that turns is off-white plastic and also has a small line on it (it is keyed to the shaft and therefore can't be misaligned with the shaft). I would figure that if you loosen both bounting bolts, shift it into neutral, align both matchmarks, and tighten the two mounting bolts, that everthing should be aligned properly for the switch.

Is this what your's looks like?

 

[Brain]

Oh yeah, the two mounting bolt holes are elongated to allow for some rotation. I'll take a picture if needed.

 

[Barcuss]

Brian, my TRS is part# F5LP-7F293AA. It looks just like the one you describe. In my ATSG manual it says the alignment tool part# is T93P-70010-A. I already have one on the way but I will let you know if that should happen to fall through.

Can the servo piston that I have not installed yet cause this condition of the transmission taking more power in 1st and 2nd gears? After it gets into 3rd and 4th its fine.

 

[Brain]

Alignment tool? I thought the match-markings on the case would be sufficient, but OK - can you let us know what that tool looks like?

Ony two gears rely on the application of the servo pistons: second and fourth (intermediate and OD, or rear and front, respectively).

Now, while only those two gears rely on the application of the bands, the other gears rely on those servos (and associated bands) being disengaged. Each servo has two seals - one to apply force and one to remove it. Do you remember which seal was cut (outer or inner)?

Check out post #45 on this page:
http://www.explorerforum.com/forums/showthread.php?t=117793&page=3&pp=20

 

[Barcuss]

Ok, In post #45 there is a picture of the servo with a red arrow "Seals to inside of bdy" pointing exactly where the cut is.

 

[Glacier991]

hmmm... my thoughts about a release circuit issue come to light....the "messed up" release circuit....?

 

[Barcuss]

Glacier, are you saying that this cut on the servo is a "release circuit" that could be causing this problem?

 

[Brain]

Yep, a cut seal in that larger diameter seal might keep the band from releasing all the way, meaning a band could be dragging on a drum and causing the extra power you notice it needing to be turned into heat (and wearing away friction material). There are springs that are supposed to help disengage the servos and bands, but it could be an issue.

The code 647 (3rd gear error) could be caused by this because in third gear, neither servo/band is supposed to be applied....it could cause it to go out of the 'acceptable range of gear ratios' and set the code.

Out of curiosity, which cover codes came on the 4R55E? The 4.0L A4LD had AB for the OD (front) and BB on the intermediate (back), where the 5R55E had ZC on the OD and AB on the intermediate.

 

[Glacier991]

I haven't really thought this through completely, but I had wondered if somethjing was dragging... applied but then not fully released.... as Brain noted, each servo has two lip seals on the pistons, one for each direction of travel... because there is hydraulic pressure used to "apply" the piston to the band, and simlarly, there is opposite hydraulic pressure to "release" the band. If you have a badly cut seal on the inside (the release side, needing a seal to work properly) It could be that the band is dragging a little... in older transmissions these pressures are not perfect... there are leaks in them, and your apply side could have a leak into so that it may have a slight pressure on it... and if your release side is leaking badly, you COULD (this is just a hypothesis) be dragging this band.

Just a thought... needs polish and more reseacch and thought.... just been something niggling at me.... something dragging (partial apply/release), somehow.

Interested to hear Brain's take on this... (let him do my legwork for a change...Hah ! <teasing>)

Edit note: Brain and I were typing at more or less the same time... his "reply" (not written as one) appears above. Same page.

 

[Brain]

There is a space and a hole between the two seals that vents/drains any leakage back to the pan (unless it is a huge amount), so I'm not saying that 'release' pressure is leaking over to the 'apply' side, but having a cut in the 'release' seal probably doesn't help anything.

 

[Glacier991]

And I wasn't suggesting that type of leak.... but a possible small bypass leak into the apply side and a leak past the seal cut on the release side..... remember though, this is all hypothetical.... you could buy a new piston and replace it and see! (You need to anyway)

 

[Brain]

And do remember that they are sized according to the two letter code on the cover. The cover and piston have to be sized the same (don't use an AB piston in an ZC cover).

 

[Glacier991]

I am not sure the wrong size could be used... unless it was the smaller... could it Brian? They have to fit the two bores.... Are these NEW servo pistons? IF not you get a SPANKING ! cheap parts and crucial! Old ones are like rocks! Say it isn't so fluffy...these ARE new servo pistons? Yes ?

 

[Brain]

Yeah, that's why I used the example of a smaller piston (AB or BB) in a bigger cover (ZC)....won't seal worth a damn, but it will fit into place.