Main >> Transfercase >> Factory >> BW 13-39
Borg-Warners 13-39 transfer case was marketed as Quadra-Trac. It is
different from Quadra-Trac found in later models. The BW 13-39 was
only used with an AMC version of the GM TH-400 automatic transmission
with a special long 10 spline output.
It is not bolt compatible with
any other Jeep transmission. Q-Trac is a full time four wheel drive
system that directs power to the wheel with the least traction. There
is an arrangement similar to an limited slip differential that splits
power between the front and rear driveshafts. There is a vacuum
operated emergency drive switch the locks the differential within the
transfer case, so that power is sent equally to the front and rear
axle. Differential locking is available for use in low traction
situations in high and low range. Low range (2.57:1) is an optional
unit that bolts to the back of the transfer case. There is a Mile
Marker 16% overdrive gear and chain set available for the Quadra-Trac
that effects high and low range and converts the transfer case for
part time operation.
The Quadra-Trac is an chain driven transfer case with an aluminum
case and it may have the casting number 13-39. The chain for the
Quadra-Trac is known for its short life span. The output for the front
driveshaft and the rear driveshaft is on the passenger side. The Dana
18 is a good canidate to replace a Quadra-Trac since the outputs are
the same. A transmission swap or conversion would be required to swap
in a Dana 18.
The transfer case in the pictures at the top of the page does not
have a low range. It is a full time single speed unit. The pictures
below show a transfer case with a low range.
It was used in the CJ-7 from 1976 until 1979 and earlier in other
models. It was introduced in the early 70s in full size Jeep trucks,
but it was not used after 1979 in any Jeep trucks.
Thanks to Walter Fil, Tim Weldon, and Terry Rust for help with some of
the information here.
Borg-Warner 13-39 transfer case.
Borg-Warner 13-39 transfer case.
Borg-Warner 13-39 transfer case.
Borg-Warner 13-39 transfer case.
Borg-Warner 13-39 transfer case.
Borg-Warner 13-39 transfer case.
Borg-Warner 13-39 transfer case.
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