In 1982 General Motors introduced the 700R4/4L60 transmission, which evolved into the 4L60E transmission used in current model year vehicles. There were
numerous design changes and updates during the years to correct shortcomings and improve this transmission. The major update to the friction components was
for 3-4 clutch improvement. The 3-4 clutch has been a weak area of this transmission since the beginning. At Trutech Performance Transmission all of our
kits address the 3-4 clutch update and contain all parts necessary to assemble the transmission correctly. In this guide we will explain the benefits of our
In the 4L60 type transmission the 3-4 clutch is contained in the input drum. The clutch is applied when hydraulic fluid
moves the 3-4 piston causing the 3-4 apply ring to engage the clutch. Over the years all these parts have been updated
by General Motors. In an automatic transmission it has been proven if you increase the number of frictions in a clutch
set up you can increase the torque handling capability of that particular clutch. One issue with this theory, to increase
the number of frictions the steels must be thinner to get proper clearance. The 3-4 clutch in this transmissions does not
work well with thin steels because of the inability to dissipate heat causing the steels to warp. General Motors went
from a five friction setup in 1982 to a seven friction set up with six thick steels in the later model 4L65/70E heavy duty
transmissions. However, in the standard 4L60E transmission up to 2010 model year GM used a six friction setup. All Trutech
Overhaul Modules contain the 4L65/70E seven friction, six "thick" steel clutch components. To install this clutch correctly
we have included all the additional factory parts necessary to achieve proper clutch clearance. One additional benefit to
this Overhaul Module, we have included turbulator steels for low reverse and reverse input clutches. Turbulator steels are
designed with holes strategically cut into the steel. The holes prevent a temporary fluid coupling in the reverse clutches
that would cause the reverse and forward clutches to be engaged at the same time. All OEM parts included in our Overhaul
Module are high quality and meet or exceed factory specification.
To ensure hydraulic intregrity our Overhaul Module contains three updated steel molded input drum pistons. Because of
changes to the overrun piston the overrun spring must be updated with the ACdelco spring included in the module. There
are two check valves that are very important to 3-4 clutch life. These check valves are the 3-4 exhaust check valve in
the input drum and the 3rd accumulator check valve. Both these valves have a direct effect on 3-4 clutch operation. We
include these check valves in all our kits, we consider this low cost insurance.
In this General Motors transmission bushings play a large part in hydraulic intregrity. In a lot of rebuilds, the bushings are
not replaced if they "look" good. The fact is, a small amount of wear in the bushing can cause a hydraulic leak which leads to
early clutch failure. Our recommendation is replace all bushings in your Overhaul. Not all our modules contain bushings because
the builder may already possess these, so check the listing that bushings are included if they are needed in your particular
In the 4L60 type transmission the band is applied to move the vehicle forward in the 2nd and 4th gear range. There have
been many improvements to this one component. We have found the Borg Warner OEM high energy band is an excellent choice
in street driven high performance or heavy duty applications. This band is included in our Overhaul module. In our High
Performance Build Modules we use the extra wide carbon band with heavy duty anchors. When using this extra wide band we
strongly recommend replacing the reverse input drum to give the band a new wear surface. Replacing the drum is always a
good idea but not always necessary when using the stock width band. Do not reuse the drum if it is discolored from heat
or is warped in the band apply area.
The Trutech Overhaul Module is the only Overhaul kit that addresses all the above mentioned issues. Our Overhaul Modules
are complete so there is no guess work, we have done the research. We only use high quality parts that meet or exceed
Thank you for choosing Trutech Performance Transmission for your performance transmission needs. We offer a technical assistance email service to our customers at no charge.
No purchase is required.
Our contact information
Call 1-800-762-9846 Inside USA
1-334-577-4400 Outside USA
Thank you for choosing Trutech Performance Transmission.