Success: Lessons learned: Just completed the Modified Servo Bore piston installation

[bcolins]

Installation of the Modified Servo Pistons in the 5R55W . Lessons learned.

After having the blinking overdrive light come on a few months ago, I parked my 2002 Explorer XLS 4.0 until I decided how to proceed. I spent lots of time here reading and posting questions about the O-Ring Servo Bore Fix. Hadn’t seen anything here that talked about the installation procedure, whether or not it repaired or reduced shifting problems, and how many miles the repair had lasted.

I recommend reading the instructions supplied by the people at: fordservoboretransmissionfixsolution.com first.

Here’s the link to their PDF Instructions. http://www.fordservoboretransmissio...1/1/5811077/transmission_instructions_r14.pdf

After you have read through their instructions, read my notes here. I think they will give some insight.

After talking with the supplier,..I purchased both of their modified servo bore pistons, and the modified long handled, right angle needle nose pliers they recommend.

I had the truck elevated on 4 jackstands and was laying on my back when doing this work. I think a lift would make it an easier task, but it went OK on jackstands.

I wasted the better part of the first afternoon trying to do this by myself with the exhaust in place.

Here’s what I learned:

The upper heat shield must be bent around the pre-cat before you will be able to get it out.

Its really probably easier to remove the center and front cross members, and the front portion of the exhaust system after disconnecting all the Oxygen sensors. I spent two hours on a Saturday trying to do it with the exhaust in place,…..and another couple of hours the next day with a friend assisting, trying to get the circlips out of the servo bore pistons. Yes, we used the pry bar and block of wood. A big part of the problem is not being able to see where the circlip ends are,…..and,….once you find them and get the right angle needle nose pliers in and squeeze, its still virtually impossible to get the circlip out.

The solution (for me) was to remove the front portion of the exhaust which is a Y-pipe with two pre cats and a full cat.

CAUTION: There is a high probability that some or all of the 12mm bolts that go up through the center cross member into the frame will be rusted to the extent that the heads will snap off when you attempt to remove them. One remedy for this, and the one I used, is to grind down the remaining bolt flush to the frame. Then cut the heads off four new 12mm bolts and weld them on to the frame where the original bolts are broken off and ground flat. Now, when you re-install the cross member on to the frame rails,…..you will fasten it with flat washers and Nylock nuts (my choice).

Now that the exhaust and cross members are out,….you will be able to get to the circlips with a standard pair of needle nose pliers and you will also be able to see what you are doing.

NOTE: Do spray the circlips thoroughly with a penetrating lubricant of your choice. I was reluctant to do this at first, thinking that it would make it more difficult to get a good grip with the needle nose pliers.,…..not the case.

NOTE: Rather than using the rubber bunji cord to hold the pry bar on the block of wood as suggested by the supplier, I found a ratcheting tie-down strap was FAR more functional. It allowed me to take all the servo cap pressure off the circlip, then, with my standard straight needle nose pliers compressing the circlip as far as it would go, I was able to get my small screwdriver into the gap between the circlip and large round bore that the servo cap and clip were in, on the opposite side of the circlip, …….and while forcing the screwdriver sideways along the gap, and hopefully UNDER the circlip, ATTEMPT TO PRY THE CIRCLIP UP.

NOTE: I tried several screwdrivers and other tools before finding the one that worked. The one that did the job was a small HUSKY brand (Home Depot I think) screwdriver. Not quite as small as the typical pocket screwdriver with a clip on the grip…………just a bit larger.

IMPORTANT: it had grooves across both faces of the screwdriver,….I think this may have helped in grabbing the edge of the circlip. Also, when I first tried the Husky screwdriver,…….the very fine/small tip broke off,…..it was only then, that the screwdriver was stout enough to get behind and under the circlips and pry them up.

Once the circlips are out, the caps came out fairly easily, and one servo piston came out easily as well, using an 11/64 brill bit inserted into the hole into the center of the servo.

The other servo was reluctant to come out. After unsuccessfully trying the same technique of using the drill bit as a handle to wiggle the servo out,….and prying on the servo,….I ended up using the fluted side of the drill bit much like a screw,……I clamped the drill bit into some vice-grips, then screwed the drill bit into the servo cap until it felt it had a bite on the cap,… then I used the vice grips like a handle and pulled gently, still nothing,…..until I also pryed on the cap of the servo,..THEN, IT POPPED AND CAME OUT!

INSTALLING THE MODIFIED SERVOS

To install the new/modified servos,………..YOU WILL DEFINITLY NEED TWO PEOPLE. Even with the ratcheting tie-down strap acting as another hand applying force to the pry-bar and block of wood to hold the Cervo cap in a compressed position, you will still want one person squeezing the needle nose pliers to compress the circlip,……and possibly ready with a screwdriver in the other hand to put pressure on a spot on the circlip that was just forced into the groove by the second person also using something like a large flat tip screwdriver.

NOTE: ONCE THE CIRCLIP IS SEATED IN THE GROOVE, YOU MUST TAP AROUND THE CIRCLIP WITH SOMETHING LIKE A DRIFT PUNCH AND HAMMER,….YOU WILL SEE THAT IT WILL MOVE FULLY INTO PLACE IN ITS GROOVE AFTER TAPPING FULLY AROUND IT.

NOTE: Now is the perfect time to ADJUST YOUR BANDS. You will see the instructions for this in the supplier’s instructions as well. Remember, because the shifts have not be fully engaging, that there has been slipping going on with most shifts, so a band adjustment is a smart thing to do at this time.

NOW YOU ARE DONE. Just re-install the exhaust system, heat shields and cross members,….and you are good to go.

WHAT WERE MY RESULTS?

So far, so good!........First of all, let me describe the issues I was having.

My 1-2 shift seemed a little slow, but firm once it happened. My 2-3 shift varied, generally I had engine rpm increase (called “flare”) in mid shift then it would sometimes engage 3rd gear, or,……it would often fumble the shift and go right to 4th gear instead. The Overdrive or 5 gear engagement came with a shudder that lasted about 2-3 seconds.

NOW. After installing the modified servo pistons,……I would say that I have about 90-95% correct shifts. If I hadn’t had weird slipping, skipping and juddering, thudding shifts from the day that I bought this truck, several months ago, I would probably say that my shifts were now normal,…….but,….I am now so sensitive to weird shifting, I am really scrutinizing each and every shift.

My main issue now is that I frequently have a bit of a faint shudder or “Thunk” with many shifts. Much better than slipping, flaring, and skipped shifts,..but still disconcerting.
As soon as the rain quits, I will do a band adjustment, hopefully that will help further clean up my shifts.

BTW, My transmission fluid was very dark brown, nearly black. After agonizing over whether to change it or not (changing burned/dark transmission fluid can in some cases cause failure of the transmission) I decided to just drain out about 3-4 quarts and refill, drive it for a while and repeat 2 or 3 times,………if it holds together,……I will do a complete drain and fill and filter in the future.

I’ll try to remember to get back here from time to time after I get some miles on the truck with an update on the fix.

If you attempt this fix,…..I hope my notes and tips here help in getting it done. Best of luck with it.

Brian in Austin