Sonnax, Author at Transmission Digest
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

TASC Force Tips: How to Avoid a Dipstick Move in 4L60-E Series Transmissions

This is certainly an issue that you should look into to ensure that your transmission has adequate fluid capacity to live a long health life.

Critical Wear Areas & Vacuum Test Locations for FORD 6R80/6R100

Note: OE valves are shown in rest position and should be tested in rest position unless otherwise indicated. Test locations are noted with an arrow. Springs are not shown for visual clarity. Low vacuum reading indicates wear. For specific vacuum test information, visit www.sonnax.com.

Hydraulics Fundamentals: Shift & Relay Valves

Shift valves and relay valves share a lot of the same duties. This article is one of a series by Sonnax exploring how valves and hydraulic circuits work and what results when they quit functioning correctly.

Hydraulics Fundamentals: Clutch Regulator Valves

Knowing how these circuits work and the slightly different variations that the manufacturers utilize should pinpoint any valve body-related issues

Transmissions & Oversized Tires

How Changing Gear Ratios Helps Prevent Drivetrain Damage

68RFE Overdrive Clutch Failure

What to Check First When Troubleshooting OD Issues

Tips for Safe Pressure Switch Removal

When disassembling a Toyota/Lexus U660E valve body, pay close attention while removing the pressure switch from the valve body.

Hydraulic Fundamentals: AFL/Solenoid Modulator Valves

Knowing your transmission’s hydraulic circuit — and solenoid circuits in particular — can be very helpful when identifying the underlying cause.

Hydraulics: Converter Limit Valves

This article is one of a series by Sonnax exploring how valves and hydraulic circuits work and what results when they quit functioning correctly.

Tasc Force Tips: Ford E4OD, 4R100

Ford E4OD, 4R100
Critical Wear Areas & Vacuum Test Locations

TASC-Tech-tip-E40D-4R100
Tasc Force Tips: Critical Wear Areas & Vacuum Test Locations

Critical Wear Areas & Vacuum Test Locations