Usage:
7271 Marine Transmission
- SUPPLEMENT: 01/10/83
SERVICE MAGAZINE, JULY 12, 1982, PAGE 1. In the article, "New Gear Type Pump Primes Itself At Start-Up," the part number of a fitting in Chart C and Illustration 3 is not correct. Change the 3B9004 part number to 1H7922.
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Description of Change: New oil lines and pump groups are used on 7271 Marine Transmissions. One group is for standard engine rotation and one is for opposite standard engine rotation. The new groups have a gear type pump that does not have to be primed (made ready for use) when used at slow engine rpm. Formerly a vane type pump was used. With the vane pump the engine rpm had to be increased to approximately 1000 rpm at the start up to prime the pump. This made it necessary to, at times, override the engine and transmission control systems to prime the pump. In some applications this increase in the engine rpm was not desirable.
A new pump drive group is used with the new gear type pump. This new drive group has all the parts needed to install the new pump on the transmission. Also, a change was made to the housing group to permit lubrication of the bearings in the new pump drive group. Two new tube assemblies and two fittings are used to connect the lubrication lines to the adapter in the pump drive group. This adapter has a drilled passage that permits the oil to flow to the bearings.
Adaptable As: The new parts are in effect on 7271 Marine Transmissions with Serial Numbers 36W321. The new parts are shown in Charts A and B. Illustrations 1 and 2 show the location of the components in the new groups.
Illustration 1. Installation of oil lines and pump group (standard engine rotation).
Illustration 2. Location of the components in the pump drive group.
To make the new groups adaptable to earlier transmissions it is necessary to make modifications to the existing oil lines in the housing group. There are two different oil line designs in earlier transmissions. The parts needed for these modifications are shown in Chart C. Chart C is divided into two different serial number ranges; which are according to the oil line design they are equipped with.
Also, reference can be made to the Service Magazine, November 30, 1981 article on page 4. This article tells about the use of a new oil supply tube assembly.
Installation Procedure:
1. Remove the top cover from the transmission.
2. Remove the ahead top shaft assembly from the transmission.
3. Remove the existing oil pump drive gear.
4. Remove the existing components of the oil pump and lines group from the transmission. Use the procedure in the Service Manual.
5. Use a 1 1/2" - 11 1/2 NPTF tap to cut threads in the oil pump outlet hole in the main case. See Illustration 1. Make sure all shavings are removed. Install a 7B9665 Plug.
6. Install the components of the pump drive group as shown in Illustration 2. Use a 6V4072 Spanner Wrench to tighten the 5B576 Nut to a torque of 400 N·m (300 lb ft)
NOTE: Remove the sharp corner from the edge of the bore in the case before the adapter and O-ring seal are installed. This will prevent possible damage to the seal when it is installed.
7. Install the parts from Chart C that are needed to supply oil to the drive. See Illustrations 3 and 4.
NOTE: On transmissions (36W1-36W262) bend the copper tubing as close to the front cover as possible. Make sure the tubing does not make contact with the ahead clutch transfer gear.
8. Install the components of the oil pump and lines group as shown in Illustration 1.
9. Install the ahead top shaft assembly. Install the top cover.
Illustration 3. Modifications for transmissions (36W1-36W262).
Illustration 4. Modifications for transmissions (36W263-36W320).