4WHEELOFFROAD.COM 4-WHEEL & OFF-ROADOCTOBER 2019 55
TH400TH400
Overview: A very buildable transmission
sought after by racers and enthusiasts
alike for racecars and trail rigs.
Found In: 1964-1990 rear-wheel-drive
and 4WD GM vehicles, including BOP cars;
also behind Buick and AMC V-8s, in some
late 1960s-1979 fullsize Jeeps, and AMC
V-8s; 1976-1979 CJs (well, not CJ-5s) as
well as behind the Buick-derived V-6 in
some Jeepsters.
Identification: Aluminum alloy case,
24.37 inches long. Oil pan has been
described as being Texas-shaped, although
we’d say it is more Ohio -shaped , but most
people don’t know what Ohio look s like.
Ratios: 2.48:1 First, 1.48:1 Second, 1:1
Third, 2:1 Reverse.
700R4/4L60700R4/4L60
Overview: With a desirable 3.06:1 First
gear and an overdrive, this transmission
can be built to withstand lots of abuse.
Found In: 1982-1992 GM two- and four-
wheel-drive fullsize trucks and SUVs.
Identification: Alloy case with integrated
bellhousing, 23.4 inches in length. Square
oil pan. Look for cases embossed with a “K”
on the passenger side of the bell that are
supposedly extra-thick and thus strong.
Ratios: 3.06:1 First, 1.63:1 Second, 1:1
Third, 0.70:1 Fourth, 2.90:1 Reverse.
4L60E
Overview: The electronically shifted evo-
lution of the 700R4/4L60.
Found In: GM full size rear-wheel- drive
and 4WD vehicles from 1992 to present.
Identification: Alloy case with integrated
bellhousing, slightly shorter housing with
a case length of 21.9 inches. Also has the
square oil pan like the 700R4/4L60. Early
versions have the four-bolt tailhousing like
the 700R4/4L60, while later (after 1997)
have a six-bolt “hex” rear output.
Ratios: 3.06:1 First, 1.63:1 Second, 1:1
Third, 0.70:1 Fourth, 2.29:1 Reverse4L60E4L80/4L85
Overview: The 4L80 is to the 4L60E what
the TH400 is to the TH350, namely a larger,
stronger transmission
Found In: 1991-2009 and later GM 2500
and 3500 trucks and vans, H1 Hummer.
Identification: Alloy case with integrated
bellhousing with a case length of 26^1 ⁄ 4
inches.
Ratios: 2.48:1 First, 1.48:1 Second, 1:1
Third, 0.75:1 Fourth, 2.07:1 Reverse4L80/4L856L80/6L90
Overview: The 6L80/90 is a heavier-
duty six-speed automatic transmission.
These transmissions were developed
alongside the Gen III/IV GM powerplants
that everyone loves these days.
Found In: 2005 and newer GM trucks
and SUVs, and some Cadillac and Pon-
tiac cars.
Identification: Alloy case with inte -
grated bellhousing with a case length
of 23^1 ⁄ 2 inches. Rectangular oil pan
with one corner rounded off.
Ratios: 4.02:1 First , 2. 36:1 Second ,
1.53:1 Third, 1.15:1 Fourth, 0.085:1
Fif th , 0.67:1 Six th , 3.06:1 Reverse. 6L80/6L90FORD
C4
Overview: The C4 transmission was
found in various rear-wheel-drive Ford cars,
trucks, SUVs, and vans behind Windsor
V-8s and Ford’s inline six-cylinder.
Found In: 1964-1981 Ford, Lincoln, and
Mercury rear-wheel-drive and 4WD cars,
trucks, and vans.
Identification: Alloy three-piece case
with bellhousing, main case, and tailhous-
ing. Overall length of 17 inches.
Ratios: 2.46:1 First , 1.46:1 Second , 1:1
Third, 2.18 Reverse.C-6C-6
Overview: A heavier-duty automatic
transmission found in larger Fords with the
inline-six, Windsor, FE, and 351M/400/460
engines.
Found In: 1966-1996 Ford, Lincoln,
Mercury rear-wheel-drive and 4WD cars,
trucks, SUVs, and vans.
Identification: Alloy case with integral
bellhousing, three different castings for
the three different engine bolt patterns,
20-inch case length with a 5.71-inch
adapter.
Ratios: 2.46:1 First , 1.46:1 Second , 1:1
Third, 2.18 Reverse.