Sean Boyle
Is It Really Necessary? 8L90 Clutch Clearance Measurement Procedures
During my presentation on the GM 8L90 transmission at Expo, I asked the group, by a show of hands, who had the special service tools that GM requires for checking clutch pack clearances. Only two or three raised their hand out of a room of 120+ rebuilders. In my presentation, I showed the group the […]

Can You Handle the Pressure? (Part 2) How to Construct an Affordable Electronic Pressure Gauge (How it Works)!
Hopefully, in last month’s article, I piqued your interest in using electronic pressure transducers and scope to measure transmission line pressure. I introduced a variety of sensors ranging from the cheap $25 eBay sensor to a higher quality sensor costing around $130. This article will show you how well those sensors perform on the inexpensive […]

Can You Handle the Pressure? (Part 1) How to Construct an Affordable Electronic Pressure Gauge
If you’ve been reading my articles in GEARS Magazine, you are probably aware that I love scopes. I think they provide a deep look into the operation of a component or vehicle system. In addition to the obvious scope uses, such as checking electrical circuits, I use scopes for everything from noise diagnostics, engine mechanical […]

Flex & Bend - A Look at the 6L80/90 JMBX Torque Converter
The GM 6L series transmission is quickly becoming the most popular attraction in the shop. As we all know, this unit is plagued by a handful of common issues, such as pressure switch filament cracking, 35R drum breakage, 1234 piston cracks, valve/bore wear, and converter failures. The drum, piston, and valve body issues are dealt […]

Jatco CVT Pressures Diagnostics
Sean Boyle featured image
When diagnosing transmission issues, there are multiple paths a technician can take to determine the fault. As technicians, we hopefully have an arsenal of tools ranging from the expensive scan tool and scope to the inexpensive test light or jumper wire and guiding our way should be the trusty service information loaded with descriptions and […]

Riding the CAN BUS to School
As technicians, we rely heavily on our scan tool. DTCs, output controls, resets, special functions, and datastreams guide our decisions on how to diagnose a problem. When we connect the scan tool and get the dreaded “No Communication” screen (figure one), the resulting frustration can often be heard across the shop. But what if there […]

Using Scopes for Diagnostics
This article is a bit of a teaser for the upcoming Powertrain Expo, coming this October in Las Vegas. We will demonstrate how to use various scopes (budget-friendly to pretty expensive) for automotive diagnostics. During that presentation, we will have a variety of scopes on hand, and we will perform live demonstrations showing their capabilities. […]

The Solenoid Regulator Valve - Too Important To Overlook!
In most automatic transmissions, you can expect to find simple switch valves that control direction of fluid and regulator valves that control or vary the amount of pressure found in hydraulic oil circuits. As technicians, we commonly focus on the pressure regulator valve and the torque converter clutch regulator valve when evaluating a valve body […]

How Much Scope Do I Really Need? Part 2
This is part two of the scope comparison series and in this article, you’ll see how the gold-standard Pico 4425, the mid-line Autel MS-408, the less expensive Pico 2204a, and Hantek 6022BE perform while measuring common automotive circuits. The following includes all four scopes measuring ignition primary and secondary, injector amperage and voltage, CAN bus, […]

How Much Scope Do I Really Need?
The aftermarket automotive service industry has been pushing scope usage for decades. Driveability shops have invested thousands of dollars into PC based scopes or scan tools with scoping abilities, but is it all necessary? For a transmission shop, it can be hard to justify spending $3000+ on a tool that might end up collecting dust […]

Torque Converter Tech with Insights from Bob Warnke
Last October, I was lucky to spend a few days with Bob Warnke, the Vice President of Technical Development at Sonnax Corporation. He did the big 13+ hour drive to come to SIU so I could help him record and edit his seminar for Expo. In exchange, I gained a wealth of information regarding torque […]

The Jatco CVT: Obstacles to the Overhaul with Insight from Robert Bateman
Think back 15 years. Would you have predicted the popularity of CVT technology? It’s amazing to think of the change in perception of the Jatco CVT since it became available in the mid-2000s, not only by consumers but also by technicians. Way back in March and April of 2007, Gears Magazine published the first two […]

ZF 9HP48 - A Mechanical Marvel!
The ZF 9HP48, also known as the 948TE for FCA (Fiat/ Chrysler Automobiles) vehicles, is a nine-speed transmission found in various Honda/Acura models, many FCA models, and a couple Land Rover models. For FCA alone, there are over 3 million of these transmissions found in the Jeep Cherokee, Renegade, Compass, the Chrysler 200, Pacifica, the […]