5R55S/W Rebuild/Enhancements

[2000StreetRod]

The 2003 Explorer Limited I'm buying has 180K on the odometer and the 5R55S transmission has never been rebuilt. The only thing the seller remembers being done to the transmission since the vehicle was purchased new by her parents was fixing the overdrive when it quit working. She thinks that entailed replacing a "solenoid" about a year ago. So the transmission is about due for a complete rebuild even though I didn't detect any upshift or downshift issues when I test drove the Limited and agreed to buy it. Since I plan to increase the engine performance (forged pistons, forged rods, DOHC heads, Mach 1 intake and possibly boost) the transmission rebuild should include enhancements capable of sustaining my cast crankshaft limit of 500 fhp.

My very limited experience with automatic transmissions includes adjusting the bands on my 1958 XK-150 Jaguar about 45 years ago and my correction of an upshift flare on my 2000 Sport due to a valve body separator plate blown gasket a few years ago. I anticipate the Limited being my last project vehicle so I'm tempted to finally learn about automatics and perform the rebuild/enhancements myself. I've watched some videos and read some shop manuals and it seems the modern transmissions require a lot less special tools, hydraulic presses, etc. to rebuild than were required for my 1950 and 1956 Oldsmobile hydramatics. Because the 5R55S was used in the mid 2000 year Mustangs there is a lot of documentation on their weaknesses and how to make them more robust. There are also many more aftermarket options than there would be if the transmission was only manufactured in SUVs.

The stock input shaft seems to be susceptible to failure when engine power exceeds 400 to 450 fhp and when it fails the torque converter may also. Even some stock 3 valve Mustangs experience input shaft failure during hard downshifts or the torque converter locking during WOT. Excess engine speed flares during upshift or downshift increase the risk of failure and one work-around is to alter the tune to reduce spark advance during upshifts with torque reduction. I think replacing the input shaft with a performance part is a prudent insurance investment.

They are typically hardened steel and machined to improve oil lubrication.

Manufacturers:

Level 10 Product Code Ford-5R55 Input
PATC P/N 5R55BIS 300M billet steel (TS = 280 to 305 ksi), may require some minor machining of the stator support
Performance Automatic P/N PA27406 hardened forged 4340 steel (TS = 185K psi)
TCI P/N 579600 Vaccu Melt 300 billet steel or Vasco 300 steel, requires some minor machining of the stator support

 

[2000StreetRod]

Tft

In my opinion knowing the transmission fluid temperature (TFT) of an operating automatic transmission is as important as knowing the oil pressure of an operating engine. Just as low oil pressure is an indication of a potential damaging condition to an engine, excessive TFT is an indication of a potential damaging condition to a transmission. Excess heat is probably the biggest enemy of the 5R55S transmission. Racing, towing and hill climbing can rapidly increase the TFT to damaging values. Ideally, the TFT should not exceed 200 degrees. Operating at 220 degrees can cut transmission life in half. The TFT should never be allowed to climb above 250 degrees. Excess TFT can be prevented with adequate external ATF cooling. Virtually all production automatic transmission equipped vehicles utilize a cooler internal to the radiator. Vehicles with the towing package have an additional auxiliary ATF cooler. Often the combination is still not adequate for performance and towing vehicles.

Aftermarket ATF coolers of various size and capacity are available to supplement the stock system. Some utilize forced air allowing efficient cooling -especially when the vehicle is not moving. In my opinion, the radiator internal ATF cooler should always be utilized because the thermal efficiency of liquid to liquid coolers is greater than liquid to air coolers. My testing with a remote sensing thermometer indicate that the radiator temperature is typically around 150 degrees even when the engine thermostat is fully open for maximum engine cooling. Available documentation for the 5R55E transmission states that the ATF external cooling loop control valve is set to open when the TFT exceeds 150 degrees F. I assume that Ford engineering determined there is an optimum TFT and it is 150 degrees. Many aftermarket transmission kits include parts and instructions to modify the valve body to force the external cooling loop control valve to remain open. The rationale is that the valve could stick closed and without a functional external loop the transmission could overheat. I think a better approach is to monitor the TFT allowing detection of a failed valve. The TFT sensor is located on the solenoid body and the external loop control valve is located in the valve body so both can be serviced without removing the transmission.

When I installed a remote ATF filter in my Sport I also installed a temperature sensor at the filter mount inlet and an A-pillar mounted display gauge. Unfortunately, if the loop control valve sticks closed the remote sensor will not detect ATF overheating in the transmission because there is no external flow. A TFT display should be sourced by a pan mounted sensor or the stock TFT sensor. I plan to install a device such as ScanGauge or UltraGauge that reads pids provided by the PCM via the OBD-II data port.

The ScanGauge head is small and can simultaneously display four pids leaving more room for parameters not available from the PCM (i.e. engine oil pressure, boost, AFR) to be displayed on traditional 2 1/16 inch dia. pod gauges.

ScanGaugeII (but not ScanGauge E) can display TFT for some vehicles. I found a post on the forum by cjp_xsport (who has a 2002 Sport) that he was able to configure his ScanGaugeII to display TFT. According to ScanGauge all 2003 and older Ford vehicles use the PWM protocol, however 2004 -2007 Fords may use PWM or CANSF. ScanGaugeII has the capability to "create" gauges using XGauge. Below is a list of available codes.

Some sensors may not be reported by the vehicle. If you try all available XGauges for a certain sensor and it doesn’t report any data then the sensor is most likely not supported by the vehicle.

The UltraGauge is taller and the controls are located on the back.

But it can simultaneously display eight pids. The UltraGauge MX is advertised to be compatible with Ford's unique protocol implemented prior to the CAN bus standard. The photo below (courtesy of Number4) shows the pids I would like displayed on an UltraGauge MX connected to a 2004 Explorer.

The photo below (courtesy of Number4) shows the pids I would like displayed on an UltraGauge MX connected to a 2003 Explorer.

Unfortunately, TFT and engine load apparently are not compatible for 2003.

I plan to install a remote mount with a full flow, high quality engine oil filter in the ATF external cooling loop. The external filter removes smaller particles than the in pan transmission filter, the external filter is easy to change, and provides additional cooling. Also, each filter change replaces a quantity of old ATF with new ATF.

 

[2000StreetRod]

torque converter

The 5R55S with the 4.6L V8 uses an 8 bolt torque converter. An adapter plate mates the 8 bolt torque converter to the stock 4 bolt flexplate.

If the torque converter is to be replaced then the adapter plate must be unbolted from it. Otherwise, the adapter plate/torque converter can be removed/installed as an assembly avoiding the need for alignment.

The photo below shows the flexplate adapter attached to the torque converter and the components.

PATC makes a torque converter adapter plate alignment tool P/N 5R55S-T that sells for $108.

The drag racing articles on torque converters I've read indicate that acceleration from a stop increases when the stall speed is increased from stock allowing the engine to operate at higher torque engine speeds. One guideline is to select a stall speed 500 to 750 rpm below max torque engine speed. A stock 2003-2004 Mach 1's torque only increases about 7 ft-lbs when engine speed increases from 2500 to 3300 rpms but increases another 18 ft-lbs when engine speed increases to 3600 rpm. This is why racers frequently have torque converters with stall speeds of 3500 to 3800 rpm or even higher. However, such high stall torque converters would not be practical for street driving.

The specified stall speed limits in my Aviator shop manual are 2545-2988 rpm after testing all forward speeds and reverse. The specified stall speed limits in my 2002 Explorer shop manual are 2557-3036 rpm for the 4.0L and 2687-3150 rpm for the 4.6L. A different 4 bolt torque converter (with no adapter plate) is installed for the 4.0L V6. What surprises me is that the Aviator engine with the same transmission has a slightly lower stall speed than the Explorer. The discount auto parts stores show the same torque converter for the Aviator and the Explorer and TSB 16971, fluid leak within converter housing applies to both vehicles.

PATC sells P/N 5R8 that fits 2005 up 4.6 Liter V8 Mustangs with the 5R55S transmission. It can be ordered with stall speeds 1800, 2000, 2200, 2400, 2600, 2800 and 3000 RPM and has all bearing construction, furnace brazed fins plus a carbon fiber clutch lining. This performance 5R55S torque converter is built using a Billet Lock-Up Clutch Piston to eliminate the piston rattling problem with the stock type piston. No core charge. Rated at 600 horse power. Cost $575.00

TCI's StreetFighter torque converter with a 3000 stall speed P/N TCI-456000 sells for $511. It fits 2005-2009 Mustangs.

It features a 10-inch, lock-up style converter that is a direct replacement for the OEM unit, a hand-built steel stator, heavy- duty clutches, furnace brazed turbine fins, a modified impellor fin angle and INA thrust bearings.

 

[2000StreetRod]

worn servo rod bores

The case of the 5R55S is made of aluminum. The bores in the case for the overdrive and intermediate servo piston rods wear allowing ATF pressure loss resulting in unreliable servo operation. The servos control the line pressure for the Intermediate and Overdrive bands. If the pressure drops enough the bands will slip when applied generating heat, rapid wear and loss of performance.

There are two ways to repair the leaking bores. One is to purchase a kit that requires disassembly of the transmission, reaming the standard bores to oversize and inserting brass bushings of the appropriate inner and outer diameter. Sonnax makes a sleeve kit P/N 56361J-01K available from Transmission Parts USA for $48.

Sonnax also makes a tool kit that includes the ream for the bores P/N S-56361J-TL available from Transmission Parts USA for $692.

The instructions for the tool kit state that a tool holding fixture is also required.

The Sonnax servo pin bore reaming fixture establishes a rigid pilot for bore repair tooling. The fixture mounts to the case, and has a floating bearing guide to ensure proper pin centerline. The P/N is Servo Fix and it's available from Transmission Parts USA for $148.

PATC offers the same capability: sleeve kit P/N 5R55SS $57; boring tool kit P/N 5R55ST $499; and fixture P/N 5R55SF $172.

The other way is to purchase a kit that doesn't require disassembly of the transmission nor bore enlargement. It can even be performed with the transmission still mounted in the vehicle. The kit is available from AJ1E Superior Solutions for $199.

Since I'm planning on rebuilding/disassembling the transmission I prefer the first method that seems more robust and the brass sleeves should last longer than the aluminum casting. However, the cost of the tool kit is not justified for a one time use. If I can't find a shop that can ream the bores to spec for a reasonable cost I may have to settle for the second method.

 

[rb142]

I don't know what they include in the tool kit for $700. That does sound pretty excessive. There must be some sort of fixture. That is a pretty simple bore job for a machine shop, and shouldn't cost very much. There are a variety of ways to do it, but I wouldn't want to do it without a mill to maintain alignment.

Hiram Gutierrez did a video (or several) on that process. He showed a tool in one of them (don't know which one). There may be cheaper options available. I think there was another Sonnax kit too that didn't require boring.

 

[2000StreetRod]

fluid pump

Apparently the fluid pump is fairly reliable because I haven't found a lot of articles on replacing or upgrading it. With rare exceptions the pumps for sale are remanufactured stock units. Its design is relatively simple.

Level 10 sells a "Super Pump" Product Code: FORDCTL-FO1400-7320 for $498.

The pump valve is critical to proper pump output, is relatively inexpensive and probably should be replaced during a rebuild. A sticking line pressure relief valve in the pump can result in a slipping transmission or even no movement of the vehicle. Superior Solutions makes a relief valve P/N K060 that "insures consistent pressure control with a no stick blow-off ball design." It costs $47.

TransGo makes a 5R55W shift kit P/N SK-5R55W that includes a "Better design no noise Pump Flow Control Valve assembly" and pump alignment tool.

It fits 5R55S/W in Explorer, Sport Trac, Mustang and Aviator and sells for $70. TransGo 5R55W-HD2 includes all of the SK-5R55W components.

Superior makes a 5R55W shift kit P/N K5R55W/N/S that appears to include pump valve but no pump alignment tool and sells for $129.

In my opinion an alignment tool is required to avoid seal leakage, gear noise, broken gears and bushing failure.

A design flaw (in my opinion) of all the 5R55 transmissions and many others is the lack of a line pressure sensor. The PCM interfaces to pressure control solenoids but I didn't find a sensor that provides a reference for the pressure. Perhaps the PCM has a "learning" capability to generate a "signature" for each solenoid to use as a future reference.

 

[2000StreetRod]

flexplate

Tasca Parts lists the 2003-2005 Aviator drive plate as P/N 1L2Z-6375-AA.

It also fits 2002-2005 Explorer 4.6L and the 2002 Explorer 4.0L.

Tasca lists the 2005-2010 Mustang GT drive plate as P/N 4R3Z-6375-BA.

I haven't determined if the Mustang drive plate will work with the Aviator block/transmission.

PATC makes an Extreme Duty Platinum Series SFI 29.1 approved flexplate P/N F6FP that fits the 1992-2008 4.6L V8 with a 6 bolt crankshaft flange. It is drilled for either a Ford or GM transmission and has a 4mm thick center-plate.

It has a 164 tooth ring gear and sells for $99. It won't bolt up to an 8 bolt torque converter but should bolt up to a 4 bolt torque converter or adapter plate.

Performance Automatic makes a SFI approved flexplate P/N PA26478-5 that fits a 6 bolt crankshaft flange (cast crankshaft).

It's 4mm thick centerplate provides a solid foundation. Ring gears are precision welded to meet SFI specifications, utilizing robotic machinery and cold welding process. JEGS sells it for $184.
Performance Automatic also makes a SFI approved flexplate package P/N PA26478-58 that fits an 8 bolt crankshaft flange (forged crankshaft).

It includes the flexplate to torque converter adapter and sells for $623.

 

[2000StreetRod]

clutches, gears & bands

According to a Hot Rod article the stock internal hard parts are good to around 500 fhp - comparable to the limit of my cast crankshaft. After market parts are available.

TCI Intermediate/OD band, Lining w/ Special Heat-Treated Struts P/N 575500 $77
TCI Reverse band P/N 575600 $54

Transmission Parts USA Intermediate/OD band P/N 23997D $21
Transmission Parts USA Reverse band P/N 23999A $34

 

[2000StreetRod]

valve body

The valve body with direction from the PCM controls the operation of the transmission. Numerous aftermarket modified valve bodies and modification kits are available.

According to The Transmission Shop in Texas one of the common problems seen is excess wear on the valve body most often seen on the torque converter clutch (TCC) modulator bore, or main regulator bore. The high duty cycle of use wears down the bore reducing clutch and servo pressures. Although the PCM tries to compensate with adaptive strategy, the excess wear will cause gear ratio or slipping codes. A Valve body repair or Update kit will usually correct these problems. You can have a gear ratio error code without having an electrical code (Solenoid) but unlikely that you will have an electrical circuit code without a gear ratio error code.

Sonnax offers a remanufactured valve body P/N F032 ($441 from Transmission Parts USA) that does not include a solenoid pack.

Sonnax recommends replacing the solenoid pack whenever a transmission problem or failure occurs, as a defective solenoid pack can produce multiple fault codes. "Every premium valve body is completely disassembled, cleaned, updated, solenoids tested and replaced as needed. Each remanufactured unit is then hydraulically and electronically tested so it’s ready to bolt up! Sonnax remanufactured valve bodies are backed by a Limited Lifetime Warranty."

Sonnax makes a line pressure booster kit P/N 5R55WS-LB1 that contain stronger pressure regulator springs and large ratio boost valves designed to work together to provide progressive pressure increases. The pressure regulator springs are approximately 10% stronger than OE. The large ratio boost valve provides higher pressure incrementally and when it is needed the most.

The combination is claimed to achieve shorter shifts and increased torque capacity without creating low-speed harshness. No special tools or reaming is required to install the kit. The kit is listed on the Sonnax website but I haven't found any seller.

The Sonnax spring that increases line pressure 10 psi more than OEM is available from Transmission Center P/N 56947J-S7 for $6.

There are rebuilt solenoid packs available but I don't know how reliable they are.

PATC sells a new OEM solenoid pack P/N 5SP for $263.

Be sure to specify 5R55S and not 5R55N.

 

[2000StreetRod]

rebuild kits

A high mileage transmission or one that has suffered failure related contamination (torque converter failure) probably justifies a complete rebuild. Identifying individual components is time consuming and usually more expensive than purchasing a complete OEM or aftermarket kit.

Ford offers master rebuilding kit P/N 7L2Z-7H575-A for $292. It includes all new clutches, steels, flex bands, sealing rings, metal clad seals, paper gaskets (valve body plate & bonded gaskets are NOT included), O-rings and gaskets. The equivalent Motorcraft master rebuilding kit P/N MTK-K2700-F can be found for $268.

PATC offers a Super Master Kit P/N 55SRMK for $378. It includes Alto Red Eagle clutches and Kolene steels plus two Red Eagle bands and an overhaul kit.

Level 10 offers a PTS Automatic Bulletproof rebuilding kit for $498. The kit includes Raybestos clutches, OEM forward bands, OEM forward Piston, OEM intermediate & O/D servos, OEM oil filter, TransTech paper and rubber with sealing rings and bushing kit, Superior Transmission Parts, pressure relief valve kit P/N K060.

Performance Automatic offers performance rebuild kit P/N PA27401 for $356. It includes seals, gaskets, and Raybestos Powertrain clutches. I haven't been able to determine what the kit actually includes.

TCI offers Ultimate Master Racing Overhaul Kit P/N 579005 for $676: "contains the performance clutches, frictions and steels made from the strongest, most durable materials available for your transmission upgrade. Best suited for applications exceeding 450 HP. These kits are perfect for extreme performance use as well as street and RV/heavy-duty towing vehicles that are under constant heavy stress. Includes Performance Clutches/Frictions, Seals, Gaskets, Bushings, Filter"
Note: The kit does not include any bands (intermediate, overdrive or reverse).

 

[2000StreetRod]

tuning

PCM tuning of the transmission related calibration constants usually can't correct for a broken part but can significantly improve the characteristics of a functional transmission. Some shift kits increase the line pressure to make shifts more firm and to reduce slippage which can extend the life of the bands and clutches. This can also be achieved with tuning. When I test drove my Sport before purchasing, at light throttle the shifts were so soft it was hard to determine when they occurred and how many forward speeds there were. A custom tune greatly improved my driving pleasure even though there was 150K miles on the odometer. I think my approach will be a modest increase in line pressure from a nonstandard fluid pump valve and a custom tune. I want the shifts to be quick and firm but not harsh whether at light throttle or WOT.

 

[skpyle]

Very interesting!
Subscribed...


Seth K. Pyle

 

[2000StreetRod]

transmission pan

After market transmission pans are available that offer one or more of the following: increased capacity; fins for cooling; fill port; sensor boss; or dipstick tube/fill port.

One issue that I have not confirmed is that a larger capacity pan will increase the time it takes for the ATF to reach normal operating temperature. I have read posts stating that the PCM will not lock the torque converter until the TFT reaches 125 deg F. This may be another argument for not installing the valve body mod that forces the external cooling loop to remain open.

PML sells a pan P/N 11066 that holds 2 to 3 more quarts than the stock Mustang pan but is only .4 inches deeper.

This heavy duty, extra capacity Ford transmission pan fits the 5R55N, 5R55S, and 5R55W transmissions found on Mustangs, Explorers, and similar vehicles.

The pan has holes for drain, fill and two level check holes to allow for a variety of applications.

Hardware included. This pan features extra capacity, straight fins, drain hole and magnetic plug, and a boss for a temperature sensor. Note to Explorer owners: the stock pan has slants at front and rear so that the stock pan can be dropped without hitting the frame cross member, exhaust pipes or catalytic converter. A stock 2004 Explorer pan is shown below.

The PML pan does not have slants. You will probably need to disconnect the catalytic converter at the header to drop the crossover pipe. A die grinder can be used to add about 0.050 inch of clearance so the PML pan does not hit the valve body, as shown below. PML pans have thick walls and flanges so this does not compromise the pan.

The two unused bosses are shown on the left, bottom of the pan. The cost is $240 for as cast finish, $295 for black power coat, and $370 for polished finish.

Performance Automatic made a deep pan P/N PA27455KT for the 2005-2010 Mustang. It included a filler tube and drain plug. However, there are very few sellers with new ones in stock.

Performance Automatic currently makes a steel pan and filler tube kit P/N PA27456 for the 2005-2010 Mustang that sells for $216.

Only the pan, dipstick and tube are included. The original gasket and drain plug must be reused. Since only the front bottom of the pan is tapered, I suspect the exhaust will have to be modified to achieve clearance on an Explorer.

Trick Flow offers two pans: P/N TFS-1012-1 consists of pan and drain plug for $175.

P/N TFS-1012 is a kit consisting of pan, tube, dipstick, bolts and drain plug for $307.

Neither of the Trick Flow pans have a boss for a sensor.

It appears that none of the above aftermarket Mustang pans will fit a stock Explorer without some modification or reduced accessibility. Therefore, I've decided to retain the stock pan making sure to have enough external cooling to keep TFT below 200 deg F.

 

[jd4242]

The pump valve is critical to proper pump output, is relatively inexpensive and probably should be replaced during a rebuild. A sticking line pressure relief valve in the pump can result in a slipping transmission or even no movement of the vehicle. Superior Solutions makes a relief valve P/N K060 that "insures consistent pressure control with a no stick blow-off ball design." It costs $47.

TransGo makes a 5R55W shift kit P/N SK-5R55W that includes a "Better design no noise Pump Flow Control Valve assembly" and pump alignment tool.
View attachment 87321
It fits 5R55S/W in Explorer, Sport Trac, Mustang and Aviator and sells for $70. TransGo 5R55W-HD2 includes all of the SK-5R55W components.

Do you know the differences in the regular kit and the HD kit?

Also do neither of these kits include the new ""relief valve"" you mentioned?

Sonnax makes a line pressure booster kit P/N 5R55WS-LB1 that contain stronger pressure regulator springs and large ratio boost valves designed to work together to provide progressive pressure increases. The pressure regulator springs are approximately 10% stronger than OE. The large ratio boost valve provides higher pressure incrementally and when it is needed the most.
View attachment 87608
The combination is claimed to achieve shorter shifts and increased torque capacity without creating low-speed harshness. No special tools or reaming is required to install the kit. The kit is listed on the Sonnax website but I haven't found any seller.

The Sonnax spring that increases line pressure 10 psi more than OEM is available from Transmission Center P/N 56947J-S7 for $6.
View attachment 87609
.

Would this not be in either of the tranGO kits either??

 

[jd4242]

?

 

[2000StreetRod]

Sorry. I didn't respond because I didn't know the answers and didn't have time to look them up. Unfortunately, most of the kits available fail to list the included parts and I'm not familiar enough with the transmission to recognize them. The only difference between the TransGo 5R55W and 5R55W-HD2 is the latter includes the parts shown below.

The only installation video I found was for the standard kit and it only covered the valve body changes. I quickly looked thru the overhaul procedures on my CD and did not identify the four items shown above. But then the shop manual only provides sketches instead of photos. I'm hoping someone else will provide some information.

 

[jd4242]

Hmm ok..guess ill give them a call to see if either kit includes a new '"'relief valve"" or a new ""boost valve""

 

[2000StreetRod]

I think I have identified the additional parts in the HD2 kit. The valve body contains two VSF modulator valves shown in the following two photos.

Since these valves are constantly moving under control of the PCM their bores in the valve body wear more rapidly than those of the standard valves. I suspect the HD2 kit includes larger diameter valves and an associated bore ream and guide.

 

[jd4242]

Think im going to stick with the regular shift kit..the HD has parts that require the trans to be pulled..im just doing solenoids,shift kit and filter for now.

Already did the servos with O-rings

 

[jsfordboy02]

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