GEARBOXES (TRANSMISSIONS)
The following gearboxes are attached to Perkins engines when supplied from production, but other boxes may be
attached by certain boat builders.
4.108
Borg-Warner 71 CR or Paragon
4.154
Borg-Warner 71 CR
4.236
Borg-Warner 71 CR or Borg-Warner 72 CR
6.354
Borg-Warner 72 CR/C or Borg-Warner 71 CR/C
T6.354*
Borg-Warner 72 CR/C
HT6.354
Borg-Warner 72 CR/C
V8.510
Borg-Warner 72 CR, 73 CR or Twin Disc MG-502
TV8.510
Borg-Warner 73 CR or Twin Disc MG-506
*Also T6.354 MGT
BORG-WARNER - Procedure for checking fluid level
The fluid level should be checked immediately after shut-down and sufficient fluid added to bring the level to the full mark
on the dipstick. The dipstick assembly need not be threaded into the case to determine fluid level. Newer gearboxes
have plug type dipsticks.
Filling - Transmission fluid (Type "A") should be added until it reaches the full mark on the dipstick. The unit should be
rotated at idling speed for a short time to fill all circuits.
The maximum interval between fluid changes for Borg Warner "Velvet Drive" marine transmission is 400 hours operating
time or 12 months (each boating season), whichever occurs first.
The condition of the fluid filter (if equipped) screen should be checked and cleaned if necessary prior to refilling the
transmission.
NOTE:
Vee Drive, 2.1:1 reduction units and CR-2 Drop Center transmissions do not have filter screens. The
filter screen for all other units is located within the cooler return/ transmission fluid drain orifice.
Fluid Pressures and Temperatures (71CR/C and 72CR/C)
Fluid Pressures should be 110-150 PSI (7.53-10.55 kgf/cm2) at normal operating temperatures of 150-165ºF (65.55-
73.8°C). At low temperatures or excessive speeds, pressure may rise to 200-250 PSI (14.06-17.58 kgf/cm2). The
maximum recommended fluid temperature is 190ºF (87.6°C).
Fluid Pressures and Temperatures (73CR)
Fluid Pressure should be 115-140 PSI (8.08 - 9.84 kgf/cm2) at 2000 rpm engine speed with a fluid temperature of 140-
190ºF (60-88ºC).
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