Technically Speaking Archives - Transmission Digest
The Subaru mystery burn

The Subaru TR580 transmission is known for having torque converter clutch solenoid failures. An example of this can be seen in Figures 1 (above) and 2 (below). The solenoid resistance should be between 10 to 13.5 ohms. The resistance right at the solenoid itself on the valve body is close to 38 ohms. And as

Tech-Speak-May-Figure-1-1400
Ford 8F24 mechanical diode failure

Mechanical diode failure in automatic transmissions is not uncommon. As far back as the AODE/4R70 shops have seen this type of failure. In April 2022 an article was published in Transmission Digest called, “The ins and outs of the Hydraulic Selectable One-Way Clutch (SOWC).” This article provided photos of the type of damage this style

Tech-Speak-April-Figure-1-1400
Sometimes, a diagnostic code is all you need

With ATSG having the opportunity to help shops solve problems, sometimes we get faced with some real doozies. A shop will call and give us a laundry list of DTCs, leaving us to think someone must have a bulkhead connector unplugged. We then go through the arduous task of deciding which codes prompted other codes

10L80 and 10R80 pump gear differences

You may have seen an article in the August 2023 issue of Transmission Digest called “GM 10L80: A new kind of pump noise,” which goes over how the front cover housing in the 10L80 is fitted with a converter drive gear and idler gear. The idler gear drives the pump’s driven gear, and is press

Spotting different 68RFE designs through the years to avoid issues

The Chrysler 68RFE has had several changes through the years. Its four-speed predecessor began with a noisy solenoid pack identified by a black colored pass-through case connector (seen in Figure 1).  In 2004, they changed to a quieter design assembly identified by a white pass-through connector (Figure 2).  This is used in all 45RFE and

Sometimes, you should sweat the small stuff

It’s a common phrase: There may have been a time when you worried about something, and someone who knew what you are going through said, “Hey, don’t sweat the small stuff.” Sometimes, this may be good advice. But other times, it may be wise to handle the small stuff before it becomes bigger “stuff.”  Fretting

Inside Toyota’s UA-UB80E/F torque converter

The UB80E/F family of transmissions used in Toyota L4 applications, and the UA80E/F used in V6 engine applications, should not be confused with the AWF8G30 transmission. Although similar, they are significantly different.  The converters used in these applications are like other known systems. Within this system, there are two very important sealing rings that need

GM 8L90 #7 Check-ball: The overheat that saved the day

Beginning in October of 2015, GM removed the #7 Check-ball from the solenoid valve control body in the 8L90 transmission (see Figure 1). This was done in conjunction with the elimination of the Lube Override Enable Valve from the upper valve body as shown in Figure 2. When this took place, the Lube Override Enable

ZF 6HP26: A torque calculation error

A 2008 Lincoln Navigator with a ZF 6HP26 transmission arrives at Holcomb’s Transmissions in limp. When checked for codes, a P1719 comes up for “Inaccurate Engine Torque Signal.” The TCM receives this over the CAN, causing it to initiate failsafe. The information Ford provides for this code is vague. The Action step provided is to

Tech-Speak-September-Figure-1-1400
Look for the little details: Three transmission repair case studies

Below are three examples of trucks that came into transmission shops, yet either did not have a transmission problem, or had a simpler issue than it originally seemed. Read on for the stories. Case study 1: Chevrolet 2500 HD Our first example features a 2006 Chevrolet 2500 HD 2WD. It has 76,257 miles on the

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The 6R140 torque converter: Common fault codes and how to rebuild

There are many reasons for converter clutch slip codes to occur in vehicles equipped with the Ford 6R140 transmission. One is bore wear in the valve body with any one of the three valves related to converter clutch apply and release. Low line pressure could be another. But there is a third that is inherent

Tech-Speak-July-Figure-1
A 10L80 with a buck and bang

A 2018 Cadillac Escalade ESV AWD 6.2L using a 10L80 transmission came in to Stroli Motors barely moving forward, making a banging noise in the center of the gearbox. Reverse was good. Keith from Stroli pulled two codes from the PCM: P0300 for Random Multiple Cylinder Misfire Detected; and P175E for Shift Limiting Active. P175E

Tech-Speak-June-Figure-1-1400