History of the T-56 Transmission
by Stan Peace, www.Pro-ForcePerformance.com
This article is a culmination of research begun in 2019; it is
periodically updated with new information and clarifications. The author
does NOT give permission to copy and re-post this on other websites without
providing credit to the author and a functioning link back to this document.
T-56
History Article
Questions, or requests for updates may be made by contacting the author through
his website.
Overview
The BorgWarner T-56 first appeared in the 1993 V-8 Camaro as a replacement
for the "somewhat fragile" T-5 transmissions hat had been used in
previous years. Tremec (Transmission Technologies Corporation - aka TTC)
acquired BorgWarner's Light-Duty Transmission Division around 1997 and the -56
transmissions were then manufactured under the Tremec name as production could
be modified.
For a Mustang, the T-56 only appeared in the 2003-2004 COBRA models from the
factory, but Tremec had already been offering aftermarket -56 transmissions for
the Ford market for several years prior.
The aftermarket T-56 line included transmissions to retrofit both Ford and GM
vehicles with both standard-ratio and close-ratio models before being replaced
with the enhanced versions called the Tremec Magnum. These are still being
made in Ford and GM styles as well as regular or close-ratio (as of 2021 at
least).
The changes to the T-56 from inception to the current Magnum product went
through several stages. The internal design of the units changed over the
years. These changes were mostly in the migration from "single"
cone synchro rings to "double " and "triple" cone synchro
rings. The early changes appeared in the Corvette, GTO, and CTS-V
models. Over time the T-56 morphed into the TR6060 since there were so
many changes and it was becoming confusing. The "TR6060"
remained the production version for new cars while the "T-56 Magnum"
versions became the aftermarket units replacing the previous aftermarket T-56
product line. So, when someone says "I have a T-56" it isn't
apparent which generation they are talking about. This is why I call the
original style T-56 the "Classic" T-56. It was made pretty much
the same way for several years.
Output Shaft Connection
The "Classic" T-56 had a 27 spline output shaft matching that of the
GM T-5 transmissions from previous years. This shaft was a bit weak and
had a tendency to snap under high torque. Thus the "Viper" 56
had a 30 spline output shaft. That shaft was a popular upgrade for the
classic models. A surprising thing was that the 2003-2004 Mustang COBRA
T-56 used the GM style 27 spline yoke even though other parts of that shaft were
unique to the Ford application.
Gear Sets
Here are some of the most common gear ratio sets used:
Camaro/Firebird: - 26 spline in / 27 spline out
1386-000-006 3.36, 2.07, 1.35, 1.00, 0.80, 0.62
1386-000-007 2.97, 2.07, 1.43, 1.00, 0.80, 0.62
1386-000-009 2.66, 1.78, 1.30, 1.00, 0.74, 0.50
1386-000-011 2.97, 2.07, 1.43, 1.00, 0.80, 0.62
1386-000-016 2.66, 1.78, 1.30, 1.00, 0.74, 0.50
1386-000-017 2.66, 1.78, 1.30, 1.00, 0.74, 0.50
1386-000-020 2.66, 1.78, 1.30, 1.00, 0.74, 0.50
Corvette C5: - 26 spline in / 27 spline out
1386-000-023 2.66, 1.78, 1.30, 1.00, 0.74, 0.50
Corvette Z05 C5: - 26 spline in / 27 spline out
1386-000-025 2.97, 2.07, 1.43, 1.00, 0.84, 0.56
Corvette - 26 spline in / 27 spline out
TUET 1452 2.66, 1.78,
1.30, 1.00, 0.74, 0.50
TUET 1453 2.66, 1.78,
1.30, 1.00, 0.74, 0.50
Mustang 2003-2004 COBRA: - 10 spline in / 27 spline out
TUET 1694 2.66, 1.78,
1.30, 1.00, 0.79, 0.63
TUET 2060 2.97, 2.07,
1.43, 1.00, 0.80, 0.62
Mustang: - 10 spline in / 31 spline out
1386-000-012 2.97, 2.07, 1.43, 1.00, 0.80, 0.62
TUET 1259 2.97, 2.07,
1.43, 1.00, 0.80, 0.62 - mech speedo
TUET 1260 2.97, 2.07,
1.43, 1.00, 0.80, 0.62 - elect speedo
TUET 1694 2.66, 1.78,
1.30, 1.00, 0.79, 0.63
TUET 2060 2.97, 2.07,
1.43, 1.00, 0.80, 0.62
Pontiac GTO: - 26 spline in / 27 spline out
TUET 2066 2.97, 2.07,
1.43, 1.00, 0.84, 0.56
Cadillac CTS-V:- 26 spline in / flange out
TUET 2022 2.97, 2.07,
1.43, 1.00, 0.84, 0.56
TUET 5044 2.97, 2.07,
1.43, 1.00, 0.84, 0.56
Dodge Viper: - 26 spline in / 30 spline out
1386-000-003 2.66, 1.78, 1.30, 1.00, 0.74, 0.50
1386-000-005 2.66, 1.78, 1.30, 1.00, 0.74, 0.50
1386-000-014 2.66, 1.78, 1.30, 1.00, 0.74, 0.50
1386-000-018 2.66, 1.78, 1.30, 1.00, 0.74, 0.50
TNET 1247 2.66, 1.78,
1.30, 1.00, 0.74, 0.50
TNET 1806 2.66, 1.78,
1.30, 1.00, 0.74, 0.50
TNET 2062 2.66, 1.78,
1.30, 1.00, 0.74, 0.50
Chevrolet T-56 MAGNUM - 26 spline in / 31 spline out
TUET 7477 2.66, 1.78,
1.30, 1.00, 0.80, 0.63
TUET 8277 2.97, 2.10,
1.46, 1.00, 0.74, 0.50
Ford T-56 MAGNUM - 26 spline in / 31 spline out
TUET 7484 2.66, 1.78,
1.30, 1.00, 0.80, 0.63
TUET 8274 2.97, 2.10,
1.46, 1.00, 0.74, 0.50
Updated Shift Forks
The early "Classic" T-56 transmissions had an aluminum 3-4 fork, but
it was later updated to a stronger steel fork
This is a recommended
upgrade if your early T-56 has the aluminum fork,
Fluids
The Classic T-56 service manual specifies to use 4.1 quarts of Dexron-III ATF.
My recommendation would be to use Mercon-V ATF or Mobil-1 Synthetic
Multi-Vehicle ATF.
Certain very popular synthetic fluids have detergents in them that can
damage the linings of the synchro rings and should be avoided.
Gear oil, Synchromesh fluid, or high performance "Purple" fluids are
not recommended.
This article was last updated on 01/31/2021
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