BORG WARNER T-18
Overview: The Borg Warner T-18 is one
of the hardest granny-geared four-speeds
to identif y because it is nearly identical toits predecessor, the T-98, and its successor,
the T-19 (T-19 has two PTO covers, right
and left). In fact, some T-18s use the same
top cover as a T-98. Also, both the T-18
and T-19 can unfortunately be found with
underwhelming 4:1 and 5:1 First gears, as
opposed to the desirable 6.32:1 First.
Found In: 1965-1991 Ford, Jeep, and IH
vehicles (T-98s are found in 1948-1972
Fords, Jeeps, and IHs; T-19s are found in
1974-1986 Ford F-250, F-350, and IHs).
Identification: Cast iron case, cast iron
top cover; 11.87-inch case length. Disas-
sembly required to verify identity. Put the
transmission in First and spin the input
while counting the output shaft rotations
to verify First gear ratios. Some variation
in top cover shape for some of the Ford
T-18s; older Ford T-18s have Reverse up
and to the right, while newer versions
have Reverse down and to the right. Many
variations in the input shaft length of Jeep
T-18s. Generally the Ford T-18 is the best
transmission for swapping behind GM,
Ford, Jeep, and Dodge engines.
Ratios: 6. 32:1 First , 3.09:1 Second ,
1.69:1 Third, 1:1 Fourth, 7.44:1 Reverse.BORG WARNER T-18SM 465
Overview: The SM465 is the big feller in
the room. Weighing in at 175 pounds, the
SM465 replaced the SM420 in GM trucks.
Found In: 1968-1991 GM trucks
Identification: Cast iron case, cast
iron top cover retained with eight bolts,
12-inch case length.
Ratios: 6.55:1 First , 3.58:1 Second ,
1.57:1 Third, 1:1 Fourth, 6.09:1 Reverse.SM46544 OCTOBER 20194-WHEEL & OFF-ROAD 4WHEELOFFROAD.COM
JUNKYARD MANUAL TRANSMISSION SPOTTER’S GUIDE
NP435
Overview: The NP435 can be found in
any of the three domestic fullsize trucks,
but GM and a smattering of Dodge NP435s
may lack the deep First gear found in all
Ford NP435s and some Dodge NP435s. The
ones to have will have a 6.68:1 First. Other
two are 4.56:1 and 4.9:1
Found In: 1966-1992 Ford trucks; 1962-
1993 Dodge trucks; very rarely in some
1968-1972 GM trucks, some International
trucks, and other industrial applications.
Identification: Cast iron case with
an aluminum top cover. This is the only
granny- geared four-speed with an alumi-
num top cover; 10.8 inch case length. To
verify gear ratios, put the transmission in
First and spin the input while counting the
output shaft rotations.
Ratios: 6.68:1 First , 3. 34:1 Second ,
1.66:1 Third, 1:1 Fourth, 8.26:1 Reverse.NP4355-SPEEDS
AX15
Overview: A medium-duty five-speed
transmission suitable for most six-cylinder
engines. The AX15 can be adapted to some
V-8s but we’d say it is barely strong enough
for stock-powered V-8s.
Found In: 1989-1999 Jeep and Chrysler
vehicles.
Identification: Aluminum housing, 16^1 ⁄ 2
inches long. Made of three main sections, two
larger pieces on each end with one thin piece
sandwiched in the middle. 4WD versions will
have a 23-spline output and a Jeep six-bolt
pattern. May be confused with the weaker
AX5, which will have a 21-spline output.
Ratios: 3.83:1 First , 2. 33:1 Second , 1.44:1
Third, 1:1 Fourth, 0.79:1 Fifth, 4.22:1 Reverse.AX15NV3550 & NV3500
Overview: The NV3500/3550 is a slight-
ly stronger replacement for the AX15. The
NV3500 has an integrated bellhousing,
while the NV3550 has a removable bell.
Was available in Jeep, Dodge, and GM.NV3550 & NV3500