How to: 5R55W transmission servo piston removal

[Metrix]

New guy here, fantastic amount of information here.

I have a 03 Explorer with 150k on a 5R55W. It has the 2-3 flare issue. The plan was to replace it with a rebuild but if I can diagnose the fault I might just try a repair.

So far, the pan is off and it's clean aside from some clutch material on the magnet. There's somewhere around 45,000 since the last work was done it. The solenoid pack is off and everything ohms out correctly per the manual. I can see the bands and bottom out the adjuster side so they don't seem to be broken.

At this point, the trans mount is off and the y-pipe has been removed.

What I want to check next is the intermediate and overdrive servo pistons.
What I'm not sure of is, can the servo pistons be removed without the band struts falling off.

Thanks

 

[BrooklynBay]

Welcome to this forum! It's possible to remove the servos without causing any interior damage just as long as you keep the transmission horizontal without too much movement. Replace the solenoid block first before you touch the servos. The solenoid blocks tend to act up around 60K miles. The bores get worn down, and will require a repair kit from WWW.ServoBore.Com or http://www.northlandtransmission.com/servobore/5rw.asp. The transmission has to be removed in order to fix the servo bores. Here's some more information: http://www.sonnax.com/tech-articles/TS7-BW-090-093.pdf

 

[Metrix]

Thanks for the quick reply BrooklynBay.
Great info.

 

[BrooklynBay]

The servo bores tend to have a lot of wear in these transmissions for several reasons:

1. The servos are very large, and have a lot of apply pressure which causes constant rubbing inside of the bores with a lot of abrasive force.

2. The shafts of the servos are made out of steel, and the case is aluminum.

3. The design from Ford causes the servos to apply/release on a slight angle instead of in a straight line. One side of the bore will always be uneven, and look a little egg shaped when it wears down.

 

[Metrix]

That's what I plan on checking next. Originally the codes I pulled off it were P0733 and P0745.

The truck belongs to a friend and he plans on keeping it for a long time. If it were my own I wouldn't mind throwing some parts at.

After reading the Sonnax pdf I can see the possibility of the valve body being worn out too, a lot of city driving. If I could find a cheap fix I could get him by for a while.

If I have to pull the trans it will probably be better to just replace it with a rebuild. I'm looking to pull the trigger on that if I don't find anything outstanding.
I'll see what the servos look like tomorrow.

 

[BrooklynBay]

The servos sometimes separate, and dry out. # 98 in my list of useful threads has information on those codes.

 

[Metrix]

Found it. A bad intermediate servo.
This one was the hardest to remove. The snap ring notches are tough to get to when they're at the top. After I oiled up the ring and slid it around to where I could see the notches things got a lot easier.



Here's the intermediate servo. The smaller overdrive servo was OK but I'll be replacing that too.

I used the broken off piston to check the bores. The intermediate bore seemed pretty tight.
I'll guess at a couple thousands horizontally and a little more vertically. The overdrive side was slightly tighter.

A few pictures to help out the next victim.

 

[BrooklynBay]

Thanks for the update, and the excellent pictures! Clean the bores thoroughly before you replace the servos. This link has break out views with part numbers: Dead Link Removed

 

[BrooklynBay]

I'm going to make this thread a sticky in this section. Here are the servos with the springs, and measurements:

 

[BrooklynBay]

A few more pictures with information:

 

[Hitchhikingmike]

Thanks for the information.

 

[ranger7ltr]

Metrix I thank you for the visuals...

And I have a question for you.. On removing the servo covers, did you use a special tool or did you just remove the snap ring and press in on the covers? This is probably the best visual I have seen on the servos and the problems with them..

When you replaced the servos, did you move the adjustment bolts first or did you leave them as they were and just pull and replace the servo itself?

Thanks again for the pictures... It will really help me get a better idea of what I am doing when I replace mine to fix the 3-4 flare I have... I suspect the servos are bad/weak on my 5R55E since the 1-2 and 2-3 shifts are soft at part throttle, firm at full throttle, and the 3-4 shift flare at teh beginning of the shift when the band should be engaged still.. The direct clutch kicks in firmly to complete the 4th gear shift though...

 

[Metrix]

For removing the snap rings I used a $9 pair of 90 degree needle nose pliers filed down to fit in the snap ring grooves. The correct tool wasn't immediately available so I had to make one, more on that later. Also, the snap ring grooves are about 1 1/8" apart and my 1" snap ring tool wouldn't spread far enough.

My parts should be in later today and I'll start assembling it tomorrow. I'll have more pictures on how to remove the snap rings and what might be the minimal amount of components to remove in the next few days.

The biggest problem is that the floor pan hangs down below the top of the intermediate servo cover and if the ring notches are at the top it's impossible to see without a mirror.



To illustrate the problem, this picture shows the floor pan with the transmission mount removed and the trans lowered to where the drive shaft is resting at the crossmember.

 

[Metrix]

Uh oh, it might be worse than I thought.
The intermediate servo will not go far enough in the bore to put the cover on.
It's the same length as the old one.
I can see the strut through the bore and it's lined up but the piston only moves about 1/8" when pressed in. Compared to the overdrive servo which moves a good 1/4".

I'm wondering if the reason the servo cracked was something may have forced it out against the cover.
The adjustment side of the band has about two threads of play at the strut.

 

[BrooklynBay]

Maybe the band is too tight?

 

[Metrix]

Seems as though the band should be loose enough but I'll try giving it some slack and see if the the strut will fall into position on the servo side.
The strut appears to be magnetic so I may be able (with a magnetic pickup) to let off some slack on the adjustment side without having the band strut (servo side) falling out of position.

I still think I should pull the trans though. I'm past the point of return now anyway. There must be something that caused the band strut to lock up and I'm pretty sure it would do me well to find out why. I'll find out more in the next couple days.

 

[Metrix]

That was it. I loosened the bands up and both servos went right in.

 

[BrooklynBay]

Thanks for the update! It sounded like the bands were too tight from your description.

 

[ranger7ltr]

So ...

That was it. I loosened the bands up and both servos went right in.

How does the transmission work after replacing the servos? Is there any sign of shift flare at all now? Are the upshifts any firmer or more pronounced than before changing them?

Thanks again for the information...

 

[Metrix]

Good news. I took it out for a test drive today, it shifts fine through every gear. I wouldn't say it's any firmer, just nice smooth shifts through all the gears, and, no flashing dash lights. So far I'm calling it a success.

I still have a fluid level check to do and repair a couple broken off bolts at the trans crossmember. I'll have some pictures to put up after I get some free time this weekend.