5R55S Operation, Diagnostics and Components

[Natural1]

In the interest of keeping everyone informed and helping those who encounter issues, I have decided to post notes regarding most of what I have found from my manuals (see references below), personal experience, building of a few 5Rs, and the questions I encounter by PM and email on a weekly basis. This will also allow you guys to diagnose issues with your trans by yourself, to some degree.

I have posted the .pdf version below and I will change it as we find flaws or come up with symptoms that don't match the ones found in the chart. I will try to keep this edited, if needed to properly identify problems leading to the failure of these units. If you read below, you will briefly learn how the 5R operates.

By now, many of us know that the "S" in 5R55S, stands for synchronous. This means, that for one thing to take place, something else has to happen at the same time. Take your second to third shift for instance. When the transmission makes this shift, the forward clutch is holding, The forward clutch holds in every gear and does not release until, P, R or N is selected. It is what is called a "static" clutch, as once it is applied it only has to hold and deliver the engine load through its drum/clutch pack. At any rate, when the shift is commanded by the PCM, the solenoids apply the intermediate band, but they also have to release the overdrive band that was applied to give you second gear during the first to second shift. You can imagine the issues the transmission may have if this timing is off. Now if that is not enough, when this particular shift is made, the PCM and transmission are depending on the integrity of the seals in the transmission to actuate the servos (hydraulic pistons that apply pressure to bands when fluid pressure is applied to their bore) so that the bands apply. If these seal bores or seals are leaking or the bands or pin bores are badly worn, you have an issue. Now, it gets worse… Let’s say that you are holding your gears manually. Have you noticed the engine braking you have in each gear when you are in manual mode? If you let out of the accelerator when the car is accelerating, the car holds driveline RPM by applying the Low/Reverse band and engine brakes. You remember riding a bicycle? Bicycles have freewheels and your transmission has an overrun clutch like that as well. The transmission, however, can lock the freewheel (called a sprag or mechanical diode) and couple parts of the drivetrain. What happens in manual mode is this:

First gear (Manual): Forward clutch applies, Coast clutch applies, Low/Reverse band applies. The Low and Overdrive Sprags are locked. (SS-A ON)

Second gear (Manual): Forward clutch holds, Coast clutch releases, overdrive band applies, Low/Reverse band holds. The Overdrive Sprag overruns and the Low Sprag locks. (SS-A, SS-C ON)

Third gear (Manual): Forward clutch holds, Coast clutch applies, Overdrive band releases, Low/Reverse band releases and the intermediate band applies. The Low Sprag overruns and the Overdrive Sprag is locked. (SS-A, SS-B ON)

For third gear in manual mode, I don’t care how you slice it; six things have to happen simultaneously to achieve that gear.

Also, engine braking is present in 4th gear with the O/D off.

Below, is a "run-down" of the 5R's operation while in Drive (D), shifting automatically:

First gear (D): Forward Clutch applies, and Coast Clutch applies. The Low Sprag is locked. The Overdrive Sprag overruns. (SS-A, SS-D ON)

Second gear (D): Forward Clutch holds, Coast Clutch releases, Overdrive Band applies, and the Low Sprag overruns. The Overdrive Sprag is locked. (SS-A, SS-C, SS-D ON)

Third gear (D): Forward clutch holds, Overdrive band releases, and the intermediate band applies. The Overdrive Sprag is locked and the Low Sprag overruns. (SS-A, SS-B, SS-D ON)

Fourth gear (D): Forward clutch holds, Coast clutch holds, Direct Clutch applies and the intermediate band releases. The Overdrive Sprag is locked and the Low Sprag overruns. (SS-D ON)

Fifth gear (D): Forward clutch holds, Direct Clutch holds and the Overdrive band applies. The Overdrive Sprag and the Low Sprag overrun. (SS-C,SS-D ON)


Now, that has been addressed and we haven’t even stepped foot into the valve body and its role in the transmission’s operation; with all of its valves, springs and solenoids.


(Operation finished 4/6/10 - VB with pics to come)


References:
Ford 5R55N/W/S Powertrain Publication - Information necessary to delete DTC from "S" chart
ATSG 5R55W/S Techtran Manual - Operation
ATSG Transmission Digest - Information for DTC Chart
Sonnax's 5R Alphabet
RatioTek's 5R55W&S

 

[07 Boss]

Awesome dude. Just copied file to my car file. Thanks Nature Boy.

 

[Natural1]

Thanks Ed! Do you recognize most of the info? You should since I extracted it from our PM. No sense in typing it twice!

 

[07 Boss]

Thanks Ed! Do you recognize most of the info? You should since I extracted it from our PM. No sense in typing it twice!

Yeah I recognize it. I was refering to the DTC and troublshooting chart. That's good stuff to have handy. I'm starting to think I may have an issue with the pin bore wear issue in TSB 09-12-12. Would that cause an issue with the intermediate band applying properly on the 2nd to 3rd gear shift. I was actually going to go by Ford today to see what they had to say. I think my warranty runs out this month so I don't want to let it lapse if it is something that can be covered. Otherwise I'm thinking to replace the solenoid pack to see if that will solve the problem.
I remember you mentioning that in manual mode something else is going on. Since I only feel this when I'm shifting manually do you think it could have something to do with that? I don't know if it has an issue when in automatic mode because I don't know when the tranny is being told to shift so I don't know if it's hanging up in that scenerio.

 

[Natural1]

Just shooting from the hip, I'd say pin bore. Generally, you will see codes present.

 

[antonio1988]

just like I told you several times before, you are a god lol. Thanks

 

[Liberty911]

Don't need to troubleshoot yet, but added it to my reference material. Thanks!!!

 

[Pumpkinfish]

My car has been throwing the P0732 code. I have a Level Ten trans/converter and had it fully upgraded there. I am running a JDM tune and the error code only comes on in heavy traffic. Today at Atco, I made around 15 passes and never received the error all day at the track. When driving home in the horrible stop and go traffic creeping along at no more than 20mph, I received the flashing o/d light and went to the shop when I got home to find it is the P0732 code. It has happened twice and both times were in very heavy stop and go traffic. Any ideas? Could it be tune or is it definitely mechanical?

 

[MexGT]

Last Thursday I completely lost all gears on my trans, weird since I was driving normally but had this slippage, but could handle it, and drove normaly to home and everything else, next day in the morning when I tried to get the car out, SURPRISE ! lol no reverse or fwd actions.

Moving to a non-syncrhonous trans now. Less PITA.

nonetheless, very good writeup!

 

[Natural1]

My car has been throwing the P0732 code.Any ideas? Could it be tune or is it definitely mechanical?

That is one that the chart touches on well. That is generally the overdrive servo or related pin bore. The overdrive band applies to give you second (as well as 5th).

just like I told you several times before, you are a god lol. Thanks

Don't need to troubleshoot yet, but added it to my reference material. Thanks!!!

nonetheless, very good writeup!

I appreciate it, guys! Most of that chart was taken from my ATSG Trans Digest. I omitted all the non-relative information from the W & N transmissions and created an entirely new chart with a few extra notes, so I can't take complete credit. I hope to finish the thread page with the basic operation tomorrow. I will then post another attachment that goes over the valvebody and its components.

 

[kyoshosp2]

Well i am trying to figure out why mine hangs for a send before it shifts. also it shifts to 4th when i punch it before it goes into 3rd lol. and now in 3rd and 4th its like i have the brakes on when i let off the gas.... &^^%$&$* bout to burn this bitch and yes it's outta warranty

 

[zipperhead]

Any chance you could post what not to do with these 5r55s trans? IE don't run them hard until there up to temp, don't shift down from overdrive under full throttle and supercharged etc.

Thanks for the codes

 

[07 Boss]

Just shooting from the hip, I'd say pin bore. Generally, you will see codes present.

That is my main issue, no codes, I think until I get one I'm just going to deal with it.

The pin bore issue, i've read about the fix. Are those pin bores within the solenoid pack. I might just get one of those instead because I think I can replace the solenoid pcak myself as opposed to drilling out new pin bores.

 

[kyoshosp2]

Shit I shoulda bought a Manual trans... This is my first auto and im getting bummed already.

 

[Natural1]

Any chance you could post what not to do with these 5r55s trans?
Thanks for the codes

You are welcome and I really feel that's for everyone to figure out... but here you go, heat kills and neutral drops are bad..

Are those pin bores within the solenoid pack.

Nah, they are the pin bores that the servo piston pins slide in and apply pressure to the bands. I will have pictures in the near future. I may also have a fix for this in the next couple of weeks..

Shit I shoulda bought a Manual trans... This is my first auto and im getting bummed already.

Sticks suck.

 

[Natural1]

EDIT: I have attached the servo assembly photos, provided band adjustment instruction, the exploded diagram of the 5R55S transmission and respective component part numbers. Hopefully, this will help those with trans problems to understand what is actually failing.

 

[Dr Wu]

I have a question that will help me and others as well, what is the safest procedure (with the longetivity of the tranny in mind) to do a burn out at the track before launch?

Thanks for the detailed info you always provide.

 

[08gt4u]

i too would like to know.^^

 

[Natural1]

Fitst (1)- Other than the fact that I wouldn't want to use additional pump capacity to supply a static band that I don't need; I don't see any issue other than it requires the trans to simultaneously perform more functions and couples the driveline. The 1-2 shift if left in drive could possibly damage the transmission, not to mention (see page 2) the fact that most N/A cars can't power stickies in a 2nd gear burnout.

 

[08gt4u]

the problem i have found out while trying to do a burnout in drive is that the tranny shifts gears while giving it gas to the point that it dosent create enough power to heat the tires,actually it bogs the car down.with street tires i dont have a problem plus i dont heat them up, but with the drag radials there is no way i can get smoke from them in drive.