A Case of Mistaken Identity, Part 2: Impossible? - Transmission Digest

A Case of Mistaken Identity, Part 2: Impossible?

It is important that you identify the problem immediately. Do not road-test the vehicle to check out the forward speeds if you are having a problem with reverse. The reduction band must be anchored to the case by the anchor stud to prevent rotation. If you try to drive the vehicle without the stud in place, the band will rotate, wedging itself between the drum and case. This will prevent the drum from rotating and will burn the clutches that try to apply for a given gear. If the clutches lose their service ability, then the transmission must be removed.

A Case of Mistaken Identity, Part 2: Impossible?

TASC Force Tips

Author: Ed Lee

TASC Force Tips

  • Author: Ed Lee

Before digging into this article, you should first read Wayne Colonna’s article “A Case of Mistaken Identity” that appeared in last month’s Transmission Digest. If you didn’t catch it in the March issue, please take a minute or two and read it before proceeding. What follows will make a lot more sense once you have read his article.

When filling the front-wheel-drive Jatco five-speed, it is not difficult for the technician installing the transmission to mistake the band-anchor stud for the fill plug. In fact, as Wayne explained, it’s not difficult to make this same mistake twice. When you consider that the shortest R&R time is 4.5 hours on Volkswagen, and the longest R&R time is 9.6 hours on the Freelander, it is important to figure out a way to rectify this problem without removing the transmission from the vehicle.

Don’t drive if no reverse

It is important that you identify the problem immediately. Do not road-test the vehicle to check out the forward speeds if you are having a problem with reverse. The reduction band must be anchored to the case by the anchor stud to prevent rotation. If you try to drive the vehicle without the stud in place, the band will rotate, wedging itself between the drum and case. This will prevent the drum from rotating and will burn the clutches that try to apply for a given gear. If the clutches lose their service ability, then the transmission must be removed.

First you need to realize what is involved in the process of returning the band to its anchored position. The band looks like a shrunken-down version of the forward band in a 4T60-E. When the band is in its proper position in the case it looks as it is pictured in Figure 1. The anchor stud fits into the oval hole on one end of the band, and the servo pushes against the other end of the band for band apply. The natural spring tension of the band aids in its release of the drum as the servo releases its pressure on the band.

The band’s spring tension would make you think that re-installing the anchor stud into the band would be impossible. The first hurdle you have to overcome is removing the tension from the band. This can be accomplished by removing the cap from the servo cavity. Once the cap is removed you can see that the servo-release movement is limited by a snap ring. The servo piston and return spring are under the snap ring; the adjusting threads and the adjustment jam nut are above the snap ring.

Leave the snap ring in place, loosen the jam nut and back out the servo-pin adjustment until you expose about 7⁄8 inch of threads (see Figure 2). This will allow you to rotate the band closer to the position needed to re-install the anchor stud. If you have not backed the adjustment out far enough you will still have tension on the band, and if you back the adjustment out too far the band will rotate past the servo pin.

At this point, the task still looks impossible. To make it possible, chuck the anchor stud in a lathe and drill a hole down the center of the stud. An “R” drill bit is a good choice for drilling the hole, since it is the tap drill bit for 1⁄8-inch pipe threads, and you will need to plug the hole in the stud when you are finished. Don’t forget to tap the threads into the head end of the stud before proceeding. You will not want to remove the anchor stud to tap the threads once you have it back in place.

You’ll need a tool to position the band while re-installing the anchor stud. The tool shown in Figure 3 was made from 0.102-inch music wire, although any number of substitute materials can be used. The two important things are that the tool be as rigid as possible and have as much of an arch as possible and still fit down the bore of the stud. The right-angle bend of the tool will help to guide the blind end of the tool.

If the band is wedged between the drum and the case, tap it free. Center the band, then rotate the band until the servo end of the band is resting against the servo pin. The oval hole in the band will now be exposed through the anchor-stud hole in the case. Put the band-alignment tool through the center of the anchor stud as shown in Figure 4. The tool now can be used to position the band as the anchor stud is installed into the case. When the anchor stud is successfully installed into the case, plug the hole in the stud with a 1⁄8-inch pipe plug and adjust the clearance on the band.

In World War II, an Army engineering company had the motto, “Difficult tasks we do immediately; impossible tasks take a little longer.” When you’ve successfully replaced the band-anchor stud without removing the transmission from the vehicle, you’ll surely be able to relate to those soldiers.

Ed Lee is a Sonnax technical specialist and a member of the TASC Force (Technical Automotive Specialties Committee), a group of recognized industry technical specialists, transmission rebuilders and Sonnax Industries Inc. technicians. ©2005 Sonnax

You May Also Like

Sherlock Holmes Approach to an AB60 No-Move Situation

The effectiveness in diagnosing automatic transmission malfunctions is an art form. Although there are similarities among the wide varieties of transmissions on the road, each transmission has its own peculiarities. Aside from having mechanical, hydraulic, and electrical hardware systems to contend with, software/programming issues and various vehicle platforms make diagnostics much more difficult.  Using scopes provides

ab60

The effectiveness in diagnosing automatic transmission malfunctions is an art form. Although there are similarities among the wide varieties of transmissions on the road, each transmission has its own peculiarities. Aside from having mechanical, hydraulic, and electrical hardware systems to contend with, software/programming issues and various vehicle platforms make diagnostics much more difficult. 

GM 6T40 Pump Identification Guide

The 6T40 was introduced in 2008 for General Motors front-wheel-drive cars in the Chevrolet Malibu and has gone through several changes throughout its three generations, specifically in the pump area. The 6T40 is closely related to the more lightweight 6T30 and the heavier duty 6T45 and 6T50. Generation one started phasing out during the 2012

Seeing the Forest AND the Trees

They say that the proverbial phrase “I couldn’t see the forest for the trees” means that a person or organization cannot see the big picture because it focuses too much on the details. Related Articles – 4L60E Harsh 1-2 Shift – TASC Force Tips: Diagnosing 8L45 & 8L90 Shift Complaints – TASC Force Tips: Hydraulics

The Manifold Pipeway

The Honda six-speed transmission has been on the bench of many specialty shops for one reason or another (figure 1). But, for those of you who have yet to lay your hands on one, mounted on the upper side of the unit is one of the largest, if not the largest solenoid and pressure switch

8L90 Vacuum Testing

Below are the diagrams for vacuum testing GM 8L90 transmissions. Note: OE valves are shown in rest position and should be tested in rest position unless otherwise indicated. Test locations are pointed to with an arrow. Springs are not shown for visual clarity. A low vacuum reading indicates wear. For specific vacuum test information, refer

Other Posts

Shift of the shaft: Diagnosing Chrysler 48RE manual shaft issues

The TorqueFlite transmission has been around since mid-to-late 1950s. There have been many changes surrounding the manual shaft and rooster comb through the years. This transmission shaft controls the position of the manual valve that directs oil for the gear ranges, but it also is used for a Reverse light control as well as Park/Neutral

Diagnosing Ford 10R60, 10R80 and 10R140 series speed sensor issues

Ford 10-speed 10R series transmissions utilize four two-wire, Hall-effect sensors — TSS, ISSA2, ISSAB and OSS — for providing speed signals to PCM or TCM. They are supplied nine volts by a PCM or TCM and assist in the control of clutch apply/release timing that is used in determining shift quality, including TCC. Related Articles

Easy TH400, 4L80-E reverse servo setup: Craft your own tool

While not as sensitive as some shifting bands, the Reverse band adjustment on a TH400 or 4L80-E transmission is critical, and failure to get it right has tripped up even the best builders. There is nothing worse than getting the transmission installed, putting it in Reverse and then not going anywhere or having no engine

Understanding lube flow control valves in Toyota/Lexus UA/UB80 transmissions

The Toyota/Lexus UA80 and UB80 transmissions first came out in 2017 in Highlanders and Siennas. The UA80 is used in V6 applications, and the UB80 is paired with four-cylinder versions. They have been called Toyota New Global Architecture type transmissions, and alternately referred to as the “Direct Shift 8AT” eight-speed automatic transmission. This transmission was

Tasc-Tip-December-Figure-1---LFC-Valve-OE-Partial-Circuit-Diagram-1400