Heavy-Duty Converters

Meet the challengers in our heavy-duty expo The heavy-duty converter market is quickly expanding on the rebuild side of the industry. To assist in rebuilding these types of converters, review the positive and negative features listed for three of the most common heavy-duty units available. Even with the different converter designs, becoming familiar with the similarities aids in rebuilding larger units.

Heavy-duty units differ from their passenger car counterparts in many ways: one, the mere size of the converter and components creates a rugged design; two, expensive replacement parts drive the resale price of each unit higher; and three, converter core costs can be significantly higher while the core failure rate also increases, demanding a proper first-time rebuild.

While the demand for more fuel efficient vehicles increase, and the sale of heavy-duty SUVs and pickup trucks may decrease, there will always be demand for heavy-duty rebuilds. Many industries rely on the capabilities of a workhorse engine and drivetrain, which will be present in the industry for many years to come. Establishing familiarity with these units now will prevent costly mistakes during rebuild and choosing the correct replacement unit.


Positive Points

Factory furnace brazed

Roller burnished impeller hub

Available in both single and multiple clutch

Available in multiple stall speeds and torque multipliers

Easy to rebuild

Many improved replacement parts available from Sonnax and Tri-Component

Negative Points

Prone to bearing failures

Weak turbine-to-clutch engagement

High rate of complete converter failure (unusable)

Weak front cover (thin clutch surface)

Excessive wear on the front cover (clutch engagement surfaces) on multiple clutch units

Turbine hub rivets prone to failure

Positive Points

Factory furnace brazed

Capable of high-torque capacity

Durable turbine hub and clutch drive

Harden flanged-type impeller hub

Negative Points Poor roller clutch design

Poor torque capacity (diesel version)

Clutch piston prone to excessive wear on o-ring surface

Multiple clutch unavailable

Front cover suseptable to pilot cracks and leaks, and poor mounting pads

Needs heavier designed bearings

Cores hard to locate

Image General Motors

Positive Points

Factory furnace brazed

Roller burnished impeller hub

Heavy-duty bearing design

More than adequately designed liner

Strong roller clutch and stator design

Multiple designs for numerous applications

High core accessability

Negative Points

Poor torque multiplication

Front cover failure around pad welds

Available only as a single-clutch unit limiting its torque capacity

Expensive core, hard to locate

– Found in September 2006 Newsletter