Evaluating 5R55S/W to 6R60 upgrade

[2000StreetRod]

It is commonly recognized that the 5R55E/S/W transmission series is significantly less robust than the 4R70W. The stock 5R55S/W has marginal reliability when coupled with the stock 4.6L V8. Since I'm planning to increase the flywheel horsepower (fhp) of a 4.6L by replacing the 2 valve heads with 4 valve heads and possibly boosting the engine, I'm looking at transmission upgrade options. In 2006 Ford upgraded the Explorer from the 5R55S/W to the 6R60 transmission probably to complement the higher fhp 3 valve V8. Since the 6R60 bolts up to the 4.6L I decided to investigate replacing the 5R55S/W with a 6R60.

I searched the forum and found a few threads questioning the possibility of the swap but nobody had tried it. I then searched the internet hoping to find a Mustang upgrade. There were lots of threads discussing the swap but nobody had actually tried it.

The 6R60 is Ford's version of the ZF 6HP26 used in Audi, BMW, Jaguar, Land Rover and Maserati vehicles. I suspect the main obstacle preventing others from incorporating it in older vehicles is the interface to the PCM. The 5R55S/W has discrete electrical lines from the shift, pressure control and torque converter clutch control solenoids to the PCM. The 6R60 has an internal transmission control unit (Mechatronic) that controls the solenoids. The Mechatronic interfaces to the PCM via the CAN bus. I assume that the Mechatronic receives engine data from the PCM and transmits transmission data to the PCM.

With the 5R55S/W transmission user gear selection comes from the Digital Transmission Range (DTR) sensor as a 4 bit binary code. The frequencies of the output shaft speed (OSS), turbine shaft speed (TSS) and intermediate shaft speed (ISS) sensors allows the PCM to determine shift scheduling, torque converter engagement schedule, and pressure requirements. With the 6R60 the same sensors provide the data internally to the Mechatronic which makes the schedule and pressure determinations. The 6R60 external interfaces pass thru the bulkhead connector located at the rear of the transmission on the right side.

Below is a diagram of the connector followed by the pinout.

Pin Signal name
. 1 Series line
. 2 CAN low
. 3 ISO K
. 4 not used
. 5 not used
. 6 CAN high
. 7 not used
. 8 not used
. 9 TCM Terminal 15 (wake up signal)
10 "P" signal (starter inhibit)
11 not used
12 not used
13 TCM Terminal 31-1 (ground)
14 TCM Terminal 30 (supply voltage)
15 not used
16 TCM Terminal 31-2 (ground)

Developing a 6R60 compatible interface would require modifying the 3rd generation PCM electrically to support the CAN bus and changing the proprietary PCM source code to match the 6R60 defined inputs and outputs. This is what Ford did in the 4th generation models to incorporate the 6R60. I have eliminated this as an option.

Another possibility is to use the 4th generation PCM in a 3rd generation Explorer. That would require making all the other 3rg generation interfaces compatible with the 4th generation PCM and will be investigated in the future.

A third possibility is to utilize the stock 3rd generation PCM and remove the Mechatronic and interface directly to the sensors and solenoids as is done with the 5R55S/W. The 5R55S/W case connector that contains the solenoid signals and the ATF temperature signal is located on the left side of the transmission behind the DTR sensor.

The pinout is shown below.

If it is determined that either of the above possibilities requires modification to the PCM source code (modifying calibration constants is allowed and does not apply) the option will be abandoned.

 

[2000StreetRod]

6R60 electrical reliability

The 6R60 is mechanically more robust than the 5R55S/W but has some electrical reliability issues. Many owners complained about a "bump" during light braking at vehicle speeds below 10 mph. There were also complaints of delayed engagement into Drive from Park, Neutral or Reverse. Additionally, after braking to a stop there is tip-in hesitation when accelerating. TSB 04-8-16 was issued to implement correction of these symptoms by recalibrating the TCM (Mechatronich) and PCM. Unfortunately, the "learing" capability of the Mechatronich eventually minimizes the TSB improvement. The Mechatronich also seems susceptible to erroneous communication with the PCM. I suspect this is due to the harsh Mechatronich environment. It is immersed in ATF which is corrosive to electrical contacts and can become hot when the transmission is under load for an extended period. The electrical contact corrosion can be reduced or eliminated by applying sealant. Additional ATF cooling capability may increase the Mechatronich electrical reliability but my preference is to eliminate its function and interface directly to the PCM with discrete and analog signals.

 

[2000StreetRod]

6R60 versions

There are two different versions of the ZF 6: the 2002-2005, ZF 6HP/19, 26, 32; and the 2006 to current 6HP/21, 28, 34. In 2006, the Mechatronic unit was upgraded to improve shift response. The later version eliminated the SS1/ Reverse engagement accumulator and has revised EDS solenoids. The “M” version has a mechanical linkage to position the manual valve. The “E” version uses a solenoid to position the manual valve and park lock. The 2002 to 2005 “M” version, has three yellow and blue solenoids, the 2006 and later “M” version, has two orange EDS solenoids. Within both vintages there is an “M” version manual valve and the “E” solenoid controlled manual valve. The “E” version in both early and late will have nine solenoids, one visible at the end of the manual valve. Below is a photo of the manual version.

The red arrow identifies the manual shift lever and the blue arrow identifies a small section of the Mechatronic. Like the 5R55S/W the 6R60 shift selector is on the left side of the vehicle.

The two plugged ports forward of the shift selector connect to the external cooling system.

 

[2000StreetRod]

shift selector

A review of the 2003 Explorer and 2006 Explorer Owners Manuals revealed only a minor difference in shift selection for the 5 speed vs the 6 speed. The selector positions are identical: P, R, N, D, 3, 2, 1. Gears available are the same except for D which allows gears 1 thru 5 for the 5 speed and 1 thru 6 for the 6 speed. The transmission control switch prevents 5th when activated on the 5 speed and 5th and 6th when activated on the 6 speed. I don't know if the movement of the lever mounted on the side of 6R60 is the same as that for the 5R55S/W. If not, it shouldn't be difficult to fabricate a lever on the needed length.

Below is a diagram of the wiring for the 5R55S/W DTR sensor for an Explorer and an Aviator which does not include the "3" position.

I had to find a wiring diagram for a Mustang GT to get an accurate wiring diagram showing the "3" position.

The Gray/Red wire is a common return. The rotating pole of each switch is connected to an associated PCM pin. When rotating pole is connected to common the PCM "reads" the position as 0. When the rotating pole is open the PCM reads the position as 1. The binary codes are as follows:

Pos TR4 TR3 TR2 TR1
. P .. 0 .. 0 ... 0 ... 0
. R .. 1 .. 1 ... 0 ... 0
. N .. 0 .. 1 ... 1 ... 0
. D .. 1 .. 1 ... 1 ... 1
. 3 .. 1 .. 0 ... 1 ... 0
. 2 .. 1 .. 0 ... 0 ... 1
. 1 .. 0 .. 0 ... 1 ... 1

It may be possible to mount a 5R55S/W DTR sensor on the 6R60.

 

[2000StreetRod]

solenoids & sensors

5R55
The 5R55S/W has 4 On/Off solenoids for shifting, one Pulse-Width Modulated (PWM) solenoid for Torque Converter Clutch (TCC) control and 3 Pressure Control (PC) solenoids (PC-A, PC-B and PC-C) for line pressure control, band and clutch application pressure. It has 4 sensors: transmission fluid temperature (TFT) sensor; turbine shaft speed (TSS) sensor; output shaft speed (OSS) sensor; and intermediate shaft speed (ISS) sensor. All are shown on the wiring diagram below.

The TFT sensor is located on the solenoid valve body. The PCM monitors voltage across the TFT sensor thermistor to determine transmission fluid temperature. Depending on temperature, the PCM regulates control pressure, shift scheduling and TCC operation. Malfunction of the sensor will cause incorrect line pressure and possible lack of TCC operation.

The TSS sensor is a magnetic pick-up that sends turbine shaft speed signal to the PCM. The TSS sensor is located on the transmission case. A malfunction of the sensor may cause increased engine RPM on engagements, harsh shifts or delayed shifts with hard apply.

The OSS sensor is a magnetic pickup located on the outside of the transmission case at output shaft ring gear. The OSS sensor sends output shaft speed signal to the PCM. The OSS sensor output is used for Torque Converter Clutch (TCC) control, shift scheduling and to determine control pressure. A malfunctioning OSS sensor may cause harsh engagements, firm shift feel or abnormal shift schedule. Unexpected downshifts may occur at closed throttle. The TCC may not engage.

The ISS sensor is a magnetic pick-up that sends planetary sun gear speed information to the PCM. The ISS sensor is mounted externally on the center of the transmission case. The PCM uses ISS sensor information to aid in determining pressure requirements.

5R55 Solenoid Operation Chart

The 5R55S/W has the following features: a 4-element torque converter with Torque Converter Clutch (TCC), 3 compound planetary gear sets, 3 bands, 3 multi-plate clutches and 2 one-way clutches.

6R60
Six Electronic Pressure Regulator Solenoids (EPRS) are located in the valve block. The solenoids are controlled by Pulse width Modulation (PWM) signals from the TCM. The solenoids convert the electrical signals into hydraulic control pressure proportional to the signal to actuate the spool valves for precise transmission operation. Solenoids EPRS 1, 3 and 6 supply a lower control pressure as the signal amperage increases and can be identified by a black connector cap. The TCM operates the solenoids using PWM signals. The TCM monitors engine load and clutch slip and varies the solenoid duty cycle accordingly. The solenoids have a 12V operating voltage and a pressure range of 0 - 4.6 bar (0 - 67 lbf.in2). Solenoids EPRS 2, 4 and 5 supply a higher control pressure as the signal amperage increases and can be identified by a green connector cap. The solenoids are normally open, regulating flow solenoid valves. The TCM operates the solenoids using a PWM earth proportional to the required increasing or decreasing clutch pressures. The solenoids have a 12V operating voltage and a pressure range of 4.6 - 0 bar (67 - 0 lbf.in2). The resistance of the coil winding for the EPRS solenoids is 5.05 ohms at 20°C (68°F).The following table shows EPRS and their associated functions:

A shift control Solenoid Valve (SV) is located in the valve block. The solenoid is controlled by the TCM and converts electrical signals into hydraulic control signals to control clutch application.

6R60 Solenoid Operation Chart

Brake and Clutch Operation Chart

 

[Explorer_PL]

Hi StreetRod

I see you did exactly same research as I did in the past 2 weeks.
As I am sure you read my questions and post about my issues with my 6r60. I ordered a rebuilt valve body, so I'll be posting whether it fixed my issues in the next 2 weeks probably. I was also surprised that the 6R is basically 6HP. That helped since goggling just 6r60/6r80 returned some info, but going wider with 6HP, it helped a lot.
I still think 6r is pretty good tranny. I never dropped the pan and maybe that was my mistake. I only did flushes every 60k miles. I take care of my car, but it works hard. All type of trailers plus pushing the snow. At 200k the torque converter locked up, and now at 213k, the mechatronic is probably bad. So overall, not that bad, I know some other trannies do not make it past 150 under normal conditions.
I did not really found an article where 6R failed due to gears or clutches, everything comes back to the valve body.
Are you planning to swap the motor and tranny in your 2000 v6 ?

 

[2000StreetRod]

your post

Your post to bdavid's thread is what prompted me to start looking at the 6R60. I'm in the process of purchasing (waiting on replacement of lost title from seller) a 2003 Limited with the 2 valve 4.6L V8 with 190K miles. I'm rebuilding a 2003 Aviator 4 valve engine to replace the 2 valve engine. I hope to eventually boost the engine to about 8 psi. I'm evaluating replacing the stock 5R55S transmission with a 6R60 rather than beefing up/rebuilding the 5R55S. I suspect the Mechatronic is the least reliable major component in the 6R60.

 

[rb142]

There is no way you will ever get a 3rd gen PCM to control a 6-sped trans without extensive and deep changes to the software. That really isn't a feasible path. You would have better luck in a combination with external TCM (i.e. the mechatronic unit in the 6R60), but as you pointed out you would still need extensive changes to the PCM software to replace the internal trans controls with the CAN and control interfaces. Again, not a feasible path.

I would say that your only chance of running a 6R60 in there is with a 4th gen module, and faking everything else to work with that. But that is not going to be without problems either.

Transmission control is millions of lines of code (more than engine control) and is very tightly integrated with torque control strategy. These aren't parts you can just swap around any more like in the old days. (Unless you can find someone in the aftermarket to provide replacement modules for both engine and trans that supports this combination.)

Frankly, I would suggest you do a quality rebuild on a 5R55, put in a valve body kit if it needs it, and leave it at that, even though that is the "boring" solution. Odds are it will outlast the truck anyway.

 

[Explorer_PL]

What tranny was used in Aviator ?
It's is very ambitious and interesting project.
I was always following those in my other car forums. I did bunch of stuff to my 1990 Thunderbird SC with 3.8 sc engine, and Mazda M5R2 tranny. I was going to replace it with T5 or T56, but then the kids were born and a coupe did not really work anymore
But lots of guys were swapping 3.8 to 4.6 2 valve, but they were all using 4R70W's, and cars were simpler back then.

I almost think that getting a used 4th gen with 6r would be more realistic. They are getting cheaper and cheaper.

 

[2000StreetRod]

no software changes

rb142, I'm aware of what's involved with transmission control which is why I ruled out any option requiring PCM software changes. I have the PCM source code (8,000 pages) for a mid 1990 Mustang with auto transmission. All PCM source code is proprietary. Even if I had it for the 2003 Explorer and could determine what changes are needed I couldn't compile it into an image that could be loaded into the PCM with my SCT PowerFlash. The only changes I can make to a PCM are calibration constants that SCT supports in my Advantage III programming package. I assume the upgrade is beyond my capabilities but I decided to confirm that since it's been raining here the past two days and I can't do anything in the yard. I agree that after this exercise I'll just have the stock 5R55S/W rebuilt with commercially available performance components suitable for street driving.

Explorer_PL, the only available transmission for the Aviator was the 5R55S/W. I was only interested in the 2002 or 2003 Explorer which came without electronic throttle control. Also, I only modify vehicles as a hobby so I didn't want to purchase a newer vehicle at a higher cost and then destroy it's resale value by modifying it.

 

[2000StreetRod]

little in common for shifting

I created a table to compare the shift solenoids enabled for each selected gear for the two transmissions.

They have very little in common. It may be possible to program a logic array to enable the correct 6R60 solenoids for each set of 5R55 outputs for each selected gear. However, that wouldn't satisfy the need to have PWM control of EPRS1 thru EPRS4 when SSA thru SSD are binary (on or off). Additionally, EPRS 1, 3 and 6 require a different driver than EPRS 2, 4 and 5. So I've decided that controlling a 6R60 with a 5R55 PCM isn't a reasonable option.

I've read that with the implementation of the CAN bus and "smart" modules (i.e. instrument cluster) the VIN is embedded in each module and the validity checked before functionality occurs. So I'm not interested in pursuing the integration of a 4th generation PCM in a 3rd generation vehicle.

The last two days have been interesting but the rain is forecast to stop tonight so I'll be back to yard work tomorrow.

 

[boominXplorer]

I know it would be going "backwards" but I plan on swapping a 4.6 with 4r70w in my girls 04 Explorer when it becomes the dedicated off road beast. My choice for the 4r70w is because of its strength and reasonably priced aftermarket support. I figure I would use a 03/04 Expedition or F150 pcm. 04 is when can-bus craziness so I am not sure if I can do with out using it. I may also go with a 4r75w out of an 04 expedition, I just have not done enough research yet as my swap is a good 2 years away.

 

[Explorer_PL]

StreetRod

Thanks for the table. That explains some of the behavior I am experiencing. I get bumps and kicks when in R, which would indicate that E2 and E4 are malfunctioning. If E2 and E4 are bad, then most of the gears are affected, but my 4th gear is strong so E4 may be good, E2 may be the issue. E2 is affecting 3rd and 5th gear that I am having issues with. If I switch the OD off, I am OK, and can drive without issues.
Does that make sense ?

 

[2000StreetRod]

not going "backwards"

I know it would be going "backwards" but I plan on swapping a 4.6 with 4r70w in my girls 04 Explorer when it becomes the dedicated off road beast. My choice for the 4r70w is because of its strength and reasonably priced aftermarket support. . .

In my opinion installing a rugged and reliable transmission in a dedicated off road vehicle is not going backwards. Ford admits by their transmission name that none of the 5 speeds (55) are as robust as their 4 speeds (70 or 75) or their 6 speeds (60 or 80).

 

[2000StreetRod]

which solenoid

. . . I get bumps and kicks when in R, which would indicate that E2 and E4 are malfunctioning. If E2 and E4 are bad, then most of the gears are affected, but my 4th gear is strong so E4 may be good, E2 may be the issue. E2 is affecting 3rd and 5th gear that I am having issues with. If I switch the OD off, I am OK, and can drive without issues.
Does that make sense ?

I didn't find a 6R60 table for when overdrive is disabled. But your reasoning seems logical. From what I've read mechanicals are more reliable than the electronics so your problem is more likely EPRS2 than clutch B. Another problem is the ATF can get to the electrical contacts and corrode them making an unreliable electrical connection. I read about some sealant that can be applied to reduce the possibility of corrosion.

I was surprised that the solenoid table indicates that the torque converter clutch can be energized in all forward speeds. The actual power train design seems pretty rugged but there are several things that in my opinion need improvement. For example, the Mechatronic electrical connector should have been connected internally to the processor with a flexible cable and physically mounted to the case instead of using a "sleeve" thru the case to the connector. The sleeve frequently leaks ATF and must be replaced. Actually, I don't like the encased processor being constantly bathed in pressurized ATF that can easily exceed 200 deg F. I would have implemented an external transmission control module.

 

[Andriska]

Do not tell me why the automatic transmission with the third gear takes in "N"

 

[JW]

I started thinking about doing a 6R80 swap after reading on the Advance Adapters site that external controllers are available for it (probably for the 6R60 as well). If there were a way to remove the programming from the PCM for the transmission (essentially making it think it's in a manual trans vehicle) that may make the swap more feasible.

@2000StreetRod - were you ever able to make any headway with this?

 

[2000StreetRod]

I never pursued the idea because I don't care for the design of the transmission. I suspect the PCM could be reprogrammed to disable the auto shift capability but programming an external controller might have a long learning period to achieve desired shifts under varying operating conditions.

 

[Taipan.onwork]

It's good that I found your topic.
I was looking for a lot of information about the installation of 6R60 in Explorer 3 and could not find any details.
You collected a lot of useful information in one topic.
But I'm sorry that no one has ever been able to do this.
Is it all about programming? Can there be some deceptions giving the right signal to the transmission?

 

[gerardt1]

A shop is south Australia is currently offering a 5r55 to 6hp26 conversion upgrade for the Australian Ford falcon for $2200 Aud. Might be worth giving them a call.
http://www.fordwreckers.com.au/fg-falcon-5-speed-6-speed-auto-conversion-packages/