440-T4 / 4T60
GM
introduced a transverse (front-wheel drive configuration) automatic transmission
with overdrive in 1985. It was
known as the 440-T4. It was
hydraulically shifted and controlled, with the only electronically controlled
component being the torque converter clutch solenoid – just like the 3-speed
automatic (125-C) that was available for the Pontiac Fiero.
The 440-T4 differed from the 125-C in one major aspect besides the fact
the 440-T4 had an overdrive gear; it also had a vacuum modulator that controlled
line pressure. On the 125-C, both
line pressure and shift points are controlled by the throttle valve (TV) cable
(aka: kickdown cable). The TV cable
on the 440-T4 only controls shift points.
The individual gear ratios in the 440-T4 are as follows: 1st-2.921,
2nd-1.568, 3rd-1.000, 4th-0.705, Reverse-2.385.
The 440-T4 was available with the following differential ratios: 2.84,
3.06, and 3.33. In addition, the
440-T4 could’ve had the following drive chain sprocket ratios: (drive/driven)
35/35 and 37/33. The drive chain
attaches the input shaft to the rest of the transmission clutches, gears, and
shafts, so a change in the chain sprocket ratio will impact all gears which will
affect the overall final drive ratio.
For example, if you had a 35/35 chain sprocket set, the effective ratio
would be 1:1. And the overall final
drive ratio of your transmission will be the same as the differential gear
ratio. But if you had a 37/33
(drive/driven) chain sprocket set, the effective ratio of the chain would be
about 0.892:1. If you had this
chain sprocket ratio and a 3.33 ratio differential, the overall final drive
ratio of the transmission would be about 2.97:1.
The 440-T4
was offered with the standard GM FWD bell housing bolt pattern, which means it
would directly bolt up to both engines that were offered stock in the Fiero.
Around the 1990 model year, GM revised their transmission designation
system and the 440-T4 became known as the 4T60 (4 forward speeds, T=transverse,
60=Series, based on relative torque capacity).
Several improvements were made to the 440-T4/4T60 transmissions over the
years before production ceased by the end of the 1993 model year.
The 440-T4/4T60 is becoming a popular swap upgrade for the Fiero because
it will work with the stock Fiero engine and computer, and will offer not only a
performance increase; but will also offer a fuel economy increase over the
3-speed auto that was available for the Fiero originally.
Swapping this transmission into a Fiero requires different mounts and
axles than the stock Fiero 125-C used, but off-the-shelf parts can be purchased
to make this swap work.
I have been
able to make the OE-replacement front transmission mount from a 1992 Pontiac
Bonneville (3800 vin L) work in Fiero applications, and the OE/stock Fiero rear
transmission mount will work on the back of this transmission as long as you got
the formed/stamped steel bracket from a donor Bonneville or like-bodied car that
bolts to the left-rear of the transmission.
Some modification of the bolt holes in the Fiero’s cradle may be
necessary to ensure proper fitment.
As far as CV axles are concerned, the stock CV axles from a 1989 Pontiac 6000
that had the 2.8L V6 (vin W), 4-speed auto trans, and JA1 brake option (light
duty brakes), with no ABS should be a direct fit to make this transmission work
in a Fiero with the stock Fiero engine.
If you have done an engine swap using something other than a stock Fiero
engine and have relocated the engine (in relation to its location side to side
in the car), these axles may not be the correct length for your swap.
The
440-T4/4T60 was commonly used first in GM cars that had the 3.8/3800 V6 engines
as well as the Cadillacs with V8’s, then later with the 2.8, 3.1, and 3300 V6.
Some Cadillac applications used a viscous converter clutch (VCC) instead
of the conventional torque converter clutch all other applications used.
The Viscous clutches allowed some slippage all the time when applied and
GM had several issues with this system.
It is advisable to steer clear of the VCC versions of this transmission
whenever possible to avoid these potential problems.
It is also a good idea to find a 1991 or newer model of this transmission
since these typically had the most “fixes” installed at the factory for some
bugs and problems the earlier models had.
Earlier models of this transmission can be used if the “known” bugs are
addressed and fixed by your transmission rebuilder.
According to my transmission builder, there was NEVER a heavy-duty
version of any 440-T4/4T60 transmission produced.
4T60-E
The 4T60-E
was introduced in 1991 and eventually replaced the 4T60.
The 4T60-E is electronically shifted (by way of two computer controlled
shift solenoids), thus it does not have a kickdown cable.
Because of this, the 4T60-E cannot be used with a stock Fiero engine
unless you get some kind of stand-alone transmission controller.
The 4T60-E looks very similar to a 440-T4/4T60 transmission, especially
if it has the stamped steel side cover (see picture showing vacuum modulator and
electrical connector on the front of the transmission).
Some 4T60-E’s (especially later year models) came with a cast aluminum
side cover. The easiest way to tell
a 4T60-E apart from the 440-T4/4T60 is the 4T60-E will not have a kickdown cable
but it will have a removable differential housing cover.
The 440-T4/4T60 has the differential housing cover cast into the rest of
the case as one-piece. Thus making
differential ratio changes in a 440-T4/4T60 difficult, since the entire
transmission needs to be disassembled in order to change it.
Changing the differential in a 4T60-E is simple in caparison, since all
you need to do is remove the differential housing cover and a snap-ring.
The 4T60-E
shares the same individual gear ratios as the 440-T4/4T60 transmission.
It was available with 35/35, 37/33, or 33/37 chain sprocket ratios.
All model years of the 4T60-E could’ve had the same differential ratios
as the 440-T4/4T60. However, in
1995 model year, GM experimented with a fine pitch differential gear which were
cut in the opposite direction that they had problems with.
In 1996 model year, GM offered a fine pitch with a standard cut direction
gear set they used for the final drive that didn’t suffer from problems.
They used this same fine pitch gear set for the final drives of all
1996-newer 4T60-E’s as well as for all 4T65-E’s.
All fine-pitch final drive gear sets (reverse and standard direction cut)
had slightly different ratios than the earlier (regular pitch) design.
These ratios are: 2.86, 3.05, and 3.29.
1996 was the only year a heavy-duty version of this transmission was
offered. The heavy duty versions of
these transmissions received a larger differential, a roller bearing to support
the differential where it rode in the differential housing cover, and a larger
spline passenger side CV axle shaft.
Non-HD versions had a smaller differential, non-roller differential to
housing cover bearing, and used the standard size passenger side CV axle shaft.
Early
versions of the 4T60-E only had one torque converter clutch solenoid, and some
did not have a transmission fluid temperature sensor.
Models that only had one torque converter clutch solenoid relied on an
accumulator in the valve body to cushion converter clutch apply.
Later models deleted this accumulator and instead used a second torque
converter clutch solenoid which was pulse width modulated (PWM) to control the
apply and release rate of the converter clutch.
Pretty much all 1994-newer 4T60-Es had the PWM TCC solenoid and a fluid
temp sensor. It is advisable to use
the correct type of Powertrain Control Module (PCM) or stand-alone transmission
controller with a 4T60-E that has a PWM TCC solenoid.
Earlier PCMs or stand-alone transmission controllers that are not capable
of operating the PWM TCC solenoid should not be used with a 4T60-E that has one.
If the PWM TCC solenoid is not being operated correctly, the result could
be a slipping converter clutch or a very harsh apply rate; either of which can
damage the transmission and/or converter.
There were some early 4T60-E’s used in Cadillacs that did have the
Viscous Converter Clutch system, and these too suffered from some problems the
440T4/4T60’s that came with these same converter systems had.
So it is advisable to steer clear of these systems if you have the
choice. Later on in some
applications, GM introduced a new converter clutch control strategy function
into their PCMs. This new strategy
allowed the converter clutch to slip some at all times vs. earlier strategies
which commanded full lockup (no slip) when the converter clutch was applied.
The lining of the torque converter clutch was changed to accommodate for
the constant slip strategy. So make
sure you match the correct torque converter (and torque converter clutch) to the
PCM converter clutch control strategy and version of 4T60-E transmission you are
using.
Most all of
the 4T60-E’s you will find will have the standard GM FWD bell housing bolt
patterns. But a few were used with
the Quad-4 engines which had their own specific (and different) bell housing
bolt patterns; and these won’t work with any other engine than a Quad-4.
The 4T60-E ceased production after 1999 model year.
As far as mounts are concerned, the same transmission mounts that will
work with the 440-T4/4T60 transmissions should also work with the 4T60-E
transmission. But the 4T60-E
transmission is a little longer on the passenger’s side than the non-electronic
440-T4/4T60 transmission is. So a
shorter passenger’s side CV axle will need to be used.
4T65-E
The 4T65-E
was first introduced in the 1997 model year and eventually replaced the 4T60-E.
The 4T65-E had many more electronic components than the 4T60-E.
A computer-controlled pressure control solenoid (force motor) was
introduced to control line pressure which replaced the vacuum modulator the
4T60-E used, an input speed sensor was added, a pressure switch manifold that
monitored various gear and converter clutch fluid circuits on the valve body was
added, and only one torque converter clutch solenoid was used (and it was PWM).
All 4T65-E’s came with a cast aluminum side cover, and the electrical
connector for these transmissions is located in the top of the side cover which
faces the driver’s side of the vehicle (see picture).
Aside from that, the 4T65-E looks very similar to the 4T60-E and is also
very similar, mechanically, to the 4T60-E.
All 4T65-E’s had the fine pitch final drive gear sets which means only
three differential gear ratios were available: 2.86, 3.05, and 3.29.
The individual gear ratios the 4T65-E has are the same as what came in
the 440-T4/4T60 and 4T60-E. The
4T65-E was available with the same chain sprocket ratios as the 4T60-E.
HD versions of this transmission were only offered with the 3800 Series 2
and 3 Supercharged V6 engines as well as the LS4 V8.
Earlier
versions of the 4T65-E transmission had an external gear position switch (which
was part of the neutral safety switch that bolted onto the transmission under
where the gear shift cable arm hooks up, just like the 4T60-E had).
This switch tells the PCM what position the shifter is in.
But around 1999 model year, GM started offering some of these
transmissions with an internal gear position switch (called an Internal Mode
Switch, or IMS) which moved this function inside of the transmission.
4T65-E’s equipped with an IMS can be used in applications where a 4T65-E
that didn’t have an IMS was used.
You can use a non-IMS equipped 4T65-E in an application where an IMS-equipped
transmission was used as long as you install the external gear position switch
on the non-IMS transmission and wire it up to the PCM.
The IMS wiring passed through the main transmission connector while the
external gear position switch had its own connector.
An
important and critical design change was introduced in the 2003 model year.
GM revised the pressure switch manifold assembly and removed many of the
pressure switches from it. Because
of this, 2003-later 4T65-E transmissions are NOT compatible with 2002-older
PCMs. The older PCMs need to see
the signals from these internal gear pressure switches in order to properly
control the shift adapts and other functions within the PCM.
The pressure control solenoid operating strategies were changed as well.
It is possible to use a 2002-older 4T65-E transmission with a 2003-newer
PCM, but some tuning will need to be done to the transmission pressure control
tables in the PCM’s programming in order to make the transmission operate as
desired. 4T65-E’s are still being
produced to this day. 4T65-E’s that
were made to be used with the LS4 V8 had a special case that had starter
mounting provisions on it, and these cases are unique to LS4 applications in
that respect (even though the bell housing bolt pattern remained the same as
other V6 and 4cyl GM engines).
The
mounting holes on the front of the transmission didn’t change but the ones on
the rear did. Later versions of
this transmission will not have the holes drilled and tapped and will be missing
the structural webbing from the casting, which will mean you won’t be able to
use the Bonneville type bracket on the left-rear of these newer transmissions.
As far as CV axles are concerned, all 4T65-E transmissions had a roller
bearing in the driver’s side output shaft location which required a different
driver’s side CV axle tripot end vs. what the 4T60-E used.
Standard duty 4T65-E’s should be able to use the same passenger side CV
axle as what can be used with the standard duty 4T60-E’s.
Like with the 4T60-E HD transmission, the HD version of the 4T65-E
requires a bigger passenger’s side CV axle tripot end.
Two
different diameter torque converters were used in these transmissions.
The smaller (245mm) converters were used in standard duty applications.
And the larger (258mm) converters were used in all heavy duty and some
standard duty applications. In
2004, GM introduced a TAPShift, or Touch Activated Power Shift feature to some
of these transmissions (RPO: KB7).
These transmissions had different valve bodies and specific PCM (or TCM)
programming that allowed the transmission to be shifted manually by pushbutton
or paddleshifter controls. The
TAPShift feature will only work with the proper PCM, TCM, or stand-alone
transmission controller capable of this function.
A TAPShift capable 4T65-E can be used with a PCM, TCM, or stand-along
transmission controller that is NOT capable of making the system work.
But you should not try using a TAPShift computer system with a 4T65-E
that does not have the TAPShift capability.
Doing so could result in transmission damage.
As far as
overall strength of each of the transmissions discussed in this article is
concerned, all three are similar.
The 4T60-E is a little stronger than the 440-T4/4T60, and the 4T65-E is a little
stronger than the 4T60-E. Of course
the HD versions of the 4T60-E and 4T65-E are stronger than the non-HD versions;
but again the main difference is in the differential.
Of course the most widely aftermarket supported transmission of the three
types is the 4T65-E due to the 3800/LS4 marketplace.
Finding upgrades specific to the 440-T4/4T60 and 4T60-E has proven to be
more difficult. Elsewhere on this website
there
information about CV axles and explains what parts you might be able to use to
build your own. I also have some ID
tag deciphering information that can help you figure out what that transmission
is (and has in it for gearing) that you see sitting on the ground at a salvage
yard here: http://www.gmtuners.com/transmission/index.htm . This ID tag information is
also available in PDA / lite format so it can be easily displayed on mobile
devices. Check out:
www.gmtuners.com/pda for this version.
A wealth of information about the 4T65-E, aftermarket transmission parts,
and a performance rebuilding service can be found at:
www.tripleedgeperformance.com .