GM Archives - Page 2 of 10 - Transmission Digest
Sonnax introduces Low/Reverse servo pistons for GM TH400, 4L80-E

Sonnax has introduced new Low/Reverse servo pistons for GM applications. According to the company, the new pistons are built for GM TH400 and 4L80-E transmissions, and are made of high-strength, billet aluminum to prevent failure.

Sonnax highlights end plug kit for GM 8L90, 8L45

Sonnax highlights its O-ringed end plug kit for GM 8L90 and 8L45 transmissions. According to the company, wear on various OE end plugs in GM 8L45 and 8L90 transmissions allows critical leakage at the following circuits, default override, lube flow regulation and converter lockup/release. These pressure losses impair control of clutches, effect lube flow regulation

New GM 8L45, 8L90 Zip Kits

Sonnax has introduced two Zip Kits that target the root cause of multiple shift-related complaints and converter-related complaints, respectively, by sealing the critical circuit pressure losses in the GM 8L45 and 8L90 valve body. Kit #8L45-8L90-SHIFT-ZIP helps prevent pressure loss within the signal accumulator, clutch control and 1-3-5-6-7 accumulator piston circuits. Kit #8L45-8L90-TCC-ZIP helps prevent

A 6T70 IMS Invalid Range Signal

There are four inputs to the TCM from the position switch assembly, that indicate which transmission gear range has been selected.

Lube On Demand Valve Kit

Transtar has announced the 6T31-6T51 (6T40 Generation 3) Lube On-Demand Valve Kit. This drop-in kit reroutes fluid to a sleeved limit valve for proper cooler/lube flow and includes an O-ring to seal the path that previously allowed valuable converter feed pressure to exhaust.

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

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

6L80 Gen2 Performance Clutch Pack

The Raybestos Powertrain complete clutch pack module for 2006-up GM 6L80 transmissions features the state-of-the-art, Gen2 Blue performance friction material (p/n RCPBP-51). Gen2 is a power absorbing material that performs with very low wear, excellent fatigue strength, high durability and quick shifts with little shock for even faster times that improves performance in the 6L80

GM Genuine Parts Unveils New Logos, Expands ACDelco OE Parts on Vehicles

General Motors Customer Care and Aftersales have announced the expansion of ACDelco branded parts on GM vehicles and introduced the new marketing campaign, “Certainty Starts Here,” a video series defining the clear choice for maintenance and repair of customers’ vehicles. The new logos for GM Genuine Parts, ACDelco and GM Marine are part of an ongoing

GM 4L80/85-E 2-3 Accumulator Spring

This new Sonnax 2-3 accumulator spring (p/n 34931-01) for GM 4L80/85-E units is a direct replacement spring that has been stress relieved and shot-peened for increased durability compared to factory springs.

4L60E Harsh 1-2 Shift

The 4L60E transmission platform has been in service from 1993-2015; that’s 22 years. It amazes me when a transmission that has been around for this long can throw a new twist on a common problem and blindside you. Let us have a look at the systems and potential problems in a 4L60E that can cause

GM 4L60, 4L60/65/70-E Extra Wide Intermediate Band

Ideal for 4×4, heavy-duty and commercial use in GM 4L60 and 4L60/65/70-E units, Sonnax drop-in extra-wide intermediate band (p/n 77700-01K) is the ONLY wide band available that features OEM style high-energy material, according to the company. It’s 15% wider than the OE band, provides 15% more holding capacity, and features a 60% thicker case anchor