The owner of a 2013 Ford Mustang started to experience an erratic drivability problem on his vehicle, but only after driving it for some time. The issue was that from a stop when the transmission was supposed to take off in first gear, it didnʼt, but rather it took off in fifth gear. To make matters worse, the problem only occurred occasionally and would trigger a check engine light to boot.

The vehicle had 28,000 miles on it and was equipped with a 5.0L engine and 6R80 transmission. The transmission functioned correctly most of the time; however, as the mileage started to increase, so did the frequency of the high-gear start. The car owner returned the vehicle to the dealer a couple of times but to no avail, since the transmission shifted well during the road test and no trouble codes were found.

Finally, one day the customer was driving down the road and the shifting problem just happened to occur while in the vicinity of a repair shop that he was familiar with, so he stopped in to see what they could do. A scanner was hooked up and the vehicle was driven in order to evaluate the problem. In conjunction with the high-gear start, there were two trouble codes pulled, a P0720 and P0722, both of which refer to an OSS signal issue. Unlike other transmission models, the output speed sensor in a 6R80 is no simple chore to deal with, since it is part of an internal component.

Before turning a wrench, the technician decided to check for any factory bulletins, just in case that there was one issued relating to this problem and as luck would have it one did exist. Ford issued a technical service bulletin (TSB 13-6-8) that cited specific years of Mustang, Expedition, Navigator and F-150 trucks. The bulletin indicated that with this type of problem the solenoid connector plate (molded lead frame) could be defective.

In addition to connecting all solenoids to the harness case connector, the TSS and OSS are part of the assembly. Based upon the symptoms and TSB, the pan and valve body were removed for inspection. The pan and fluid were relatively clean so the lead frame was separated from the valve body.

In the past, an erratic high-gear start would indicate a sticking governor or valve-body shift valve; however, with newer computer-controlled transmissions other scenarios are possible. This type of problem involving newer transmissions could be due to bad or corroded connections, sticky solenoids, faulty pressure switches or excessive air gaps. The fix for the Mustang was leaning toward the lead frame.

Ford decided to follow the ZF format when the 6R60 family of transmissions was released in 2006 in regard to the computer controls. The 6R60 was a mechatronic (TEHCM) design transmission, meaning that the TCM was internal. The TCM was incorporated into the lead frame (solenoid connector plate) along with the other electrical items (Figure 1).

All that started to change on certain Ford transmission applications in 2010 when Ford engineering decided to deviate from the previous designs and remove the TCM from the lead frame. Except for the omission of the TCM, the new-design lead frame looks basically the same as the mechatronic models (Figure 2). The part number for the 2010-up non-TCM is AL3Z-7G276A. Apparently though, when the new part number was released something else was different, at least in the case of the Mustang, or the TSB would not have been issued or problems not surface.

In conjunction with the new design lead frame, Ford also decided to make a change in solenoids. Although the 6R80 transmission uses seven solenoids, there are only three basic types. Identifying the solenoid types on 2006 to 2010 from the newer designs is based upon color and barrel design. There are six PWM solenoids and one on-off type that are used in early or late models. On the early applications there are three PWM solenoids that are NL (low variable bleed) and have a brown plastic cap. The other three PWM solenoids are NH (high variable bleed) with a black plastic cap (Figure 3).

The new design solenoids can also be identified by cap color, but for a different reason. The caps are all a neutral color (yellow) because the barrels of the solenoids are either brown or black (Figure 4).

Beyond the color differences, the barrel dimensions and O-rings are different between early and late solenoids, preventing interchangeability. Fortunately, the Mustang did not require any solenoids. Ordering late model solenoids are also dependent upon a stamp number:

Once the new lead frame was installed, the Mustang was driven and worked well with no check engine light. Now, if it only stays that way.

Since the beginning of automatic transmissions nearly every component has undergone some type of change or modification relating to design, material or function. Certain items within a transmission would receive continuous upgrades, but then be “designed out” altogether. Other transmissions would be launched without a given component, only to be added in later on.

Many transmission-component improvements or redesigns were certainly valid, while others made no sense at all, at least at the time. Major transmission internal items such as a pump, planetary or valve body might warrant a facelift from time to time, while others not so much. Such is the case of the lowly cooler line fitting.

For years the cooler circuit and related items for an automatic transmission were fairly basic in design. The two main cooler line sizes were 5/16” and 3/8” in diameter and had flared ends at both the transmission and radiator. The cooler-line fittings themselves were usually either a 1/8” or 1/4” pipe thread and could be straight or at a 90°. GM and Ford applications would use an inverted nut while Chrysler chose to be backwards by having a threaded nut on the line itself (Figure 5). Other than the occasional fitting with an anti-drain back check ball installed, that was it.

A couple of decades ago, the OEMs decided that cranking in cooler-line fittings on the assembly line was cumbersome and time consuming, along with the potential leakers, so engineering needed to develop a better mousetrap. As a result, the push-in cooler line and fitting was launched. Changes were phased in based upon application, with several models utilizing both the flared and push-in designs. The key to the push-in style is rapid installation and as long as the O-rings and retainer clips are intact, leaks are normally minimal. Over the years however, there has been an unending amount of design changes affecting both sides of a cooler line fitting, resulting in a slew of part numbers.

GM RWD models such as the 4L60E and 4L80E initially used a common fitting, which was metal and had a 1/4” x 18 pipe thread. The hole in the fitting was 5/16” with an OE part number 19125677. Beginning in late 2005, things started to change with the 4L60E and front 4L80E in regards to design and material. New design fittings are now aluminum with an O-ring and what GM refers to as a 9/16” x 18 straight thread. The hole in the new fittings is now 3/8” that applies to two different part numbers, 24236554 and 24236579 (Figure 6).

When GM switched the 4L80E to the rear cooler-line design in 1997, the thread remained the same as the front fitting pipe thread, with the extended tube being the main difference. Just as with the front fitting, the rear fitting was also changed to the new thread design in late 2005. The tube diameters, however, remain the same. The early design fitting number is 24233367, with the later fitting number being 24236581 (Figure 7).

GM FWD transmission models 4T60, 4T60E and 4T65E had even more fitting changes to deal with. The horizontal fitting started out as a flared design with a 1/4” pipe thread, part number 8651654, which was also used on certain RWD applications. By 2000, the 4T65E was also changed to the push-in design. The vertical fitting, the one with the anti-drain-back check ball, has changed several times. The 4T60 fitting (24207294), 4T60E (24202550) and early 4T65E (24213958) all used a 3/8” pipe thread with the 4T65E using a push-in cooler line. By mid-2004 the vertical fitting was switched to the straight thread design and the check ball was relocated to the channel plate (Figure 8).

Lastly is the biggest mess of all, the 4T80E. The cooler fitting at the case cover end started out using a 9/16” x 18 thread and flared line, part number 8684086, but switched to a push-in design in 2004 and with a larger hole, part number 24225125. The fitting at the differential end of the case has changed several times. The first “rear” fitting was a regular 1/4” pipe thread, flared line, without a tube on certain models. Other models, however, used a flared fitting with the tube, part number 8685767. By 2002 the fitting was switched to a push in design, part number 24212855, which was metal. By 2004 the fitting material was changed to aluminum, part number 24225126, but remained dimensionally the same. Certain models 2004-up could also use the non-tube 24225125 type (Figure 9).

Ford applications havenʼt been quite as bad as GM after switching over to push-in cooler lines; however, changes do exist. The main thing to compare on Ford fittings is whether they are 5/16” or 3/8” diameter lines as well as if they have a 1/4” or 3/8” pipe thread (Figure 10). One other difference to note is whether the fitting is a clip design or not.

Chrysler qualifies for the best score when it comes to fitting simplicity. The 46/48R family push-in fittings, use a 1/4” pipe thread regardless of cooler-line diameter, which could be 3/8” or 1/2”. There is also a 1/2” diameter flared-fitting design (Figure 11). They must want to pump a lot of fluid to the radiator and back. The 45RFE models use a monster pipe thread, but with a small cooler line and the radiators may use a 1/2” line, but with a 3/8” pipe thread unlike the transmission end, go figure.

Import applications are a different matter altogether with certain fittings being common with domestic designs, while others are not even close, such as the banjo design. Before ordering any fitting, just make sure that it fills the hole and connects the line correctly.

Various problems have evolved alongside transmission development ever since the automatic transmission came into existence, whether it be noise related, power related or some sort of application issue. The problems and fixes have varied almost as much as the transmission types used over the years, with the OEMʼs and aftermarket implementing the repair, at times, from different angles. One such issue that has existed almost from the beginning is delayed garage shifts (morning sickness) and how to address it. Whether the vehicle set overnight or even for just a few hours, when the car owner would hop in, fire up the engine and put the transmission into drive or reverse, delayed engagement is unacceptable.

There have been several causes of delayed engagement, depending on transmission type, some of which being relatively minor and easy to repair with others requiring much more effort. Possible causes of delayed engagement could be loss of pump pressure, torque converter drain back, an individual component issue such as an OWC or on newer transmissions some type of electrical issue.

Pump pressure loss could be due to excessive pump gear clearance, cross leaks within the pump or valve body or a sticky valve such as the pressure regulator valve. Torque converter drain back can also be caused for the same reasons as well as having drain back through the cooler circuit. An individual component issue could be a lip seal not energizing or an air bleed check ball not seating correctly. In addition, a sprag or roller clutch may not hook up quickly. Lastly, newer transmissions with an array of electrical components such as solenoids or pressure switches can also contribute to the delayed engagement problem.

Recently, an issue has surfaced in regard to the 6R80 transmission, which comes equipped in 2011-up Ford Mustang, Expedition, Navigator and F-150 truck models. A technical service bulletin has been issued by Ford relating to this problem (TSB 14 – 0217). The TSB refers to replacement of the entire pump assembly (Figure 12).

The basic design of the pump assembly is very similar between the 6R60 and 6R80 transmissions, but with a few exceptions. The 6R60 pump uses both a front and rear input shaft bushing, whereas the 6R80 only has a rear bushing, which is larger in diameter than the 6R60 models. Beyond that, the 6R80 pump bore and input shaft are larger in diameter overall than the 6R60. There are only two sealing rings on the 6R60 input shaft, whereas the 6R80 has three.

The 6R80 pump is somewhat different from other transmissions in that, instead of a simple pump body and cover, the 6R80 has a small cast-iron pump body, an aluminum pump cover and an intermediate plate that the stator shaft bolts into. Although 6R60/6R80 transmissions have been in existence since 2006, there has been little change with the basic castings. The original Ford service part number for the 6R60 was 6L2Z–7A103AA, which was changed to 6L2Z–7A103C. The original part number for the 6R80 pump was 9L3Z–7A103A. Since it did not appear as though there were drain-back issues on earlier applications, the question remains what happened on later models that tend to have this issue.

In reference to the TSB that Ford released is the question of the pump itself. The bulletin listed not one part number but two, both of which are different from the original 6R80 pump. It remains to be seen as to what created the drain-back issue on the 2011 and up transmissions. There is a month and year break to distinguish between the two pump part numbers.

The direct replacement pump for a 2009-up 6R80 is OE part number BL3Z-7A103B, which services models to 3/31/2014. The new part number had been released for 4/1/2014-up models and is OE part number FL3Z-7A103A. There is little difference when comparing the aluminum castings from the original 6R80 pump to the newer versions. The main difference between the split 2014 applications has to do with the pump body and gears. Unlike previous models of 6R60/6R80 pumps, which used a caged bearing to ride against the torque converter hub, both of the newer applications use a pump body bushing (Figure 13).

The modification of the pump gears has to do with the pump gear driver. Since Ford followed the ZF lead initially, the pump inner gear had drive lugs like GM or Chrysler, which was contrary to what Ford has normally done. That changed with the late 2014 pump gear, which now has flats instead of drive lugs (Figure 14). The gears are now back, in the Ford family.

Regardless of the drain-back cause, use caution when ordering the replacement pump so that it matches the torque-converter hub design. Who knows, maybe just installing an anti-drain-back valve into the cooler line would get the job done as well.

November 2015 Issue
Volume 32, No. 11

• Mustang 6R80 high-gear starts
• Cooler line fitting upgrades
• Late model 6R80 drain back issue