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Gear Box Transmission Clatter in Model 275

tomboat

New member
Installed in 2015 new u joints and PDS drive shaft bearing - 220 hours ago but now have a clatter when the engine is in neutral at 800 RPMs. I checked the PDS drive shaft- it and (U Joints are tight but little rusty). When I turn U Joint Yoke connected to main shaft gear going in the transmission, there is about 1/16 inch play with the U Joint and main gear when it makes contact with one of the gears in the box and a click sound. Main shaft gear bearing seems tight. The forward and reverse gears look ok looking into the gear box and the top bearing looks OK. How much play should there be when I turn the U joint/main shaft gear and the gear inside the box? Do I need to a thicker shim to reduce the play between the clamp and the gear box? My son had boat in neutral at about 1400 RPMS and put it in reverse and said there was a loud clunk. I can remove the torsion bolt and check the splines on the U joint to see if they are bent or torsion bolt is Loose? What torque do I reset the torsion bolt at - 60 lbs - others say 90 lbs? How do I reduce the play between the main shaft gear and the gear in the box? Would back lash be an issue if its just the main shaft gear play issue? And will 20w40 oil help reduce the clatter and wear? I have reviewed my 270 stern drive manual but does not address these specific issues. Your thoughts and suggestions please. Thanks... tomboat
 
Installed in 2015 new u joints and

1..... PDS drive shaft bearing - 220 hours ago but now have a clatter when the engine is in neutral at 800 RPMs. I checked the PDS drive shaft- it and (U Joints are tight but little rusty).

2.... When I turn U Joint Yoke connected to main shaft gear going in the transmission, there is about 1/16 inch play with the U Joint and main gear when it makes contact with one of the gears in the box and a click sound.


3.... Main shaft gear bearing seems tight.


4.... The forward and reverse gears look ok looking into the gear box and the top bearing looks OK.


5...... How much play should there be when I turn the U joint/main shaft gear and the gear inside the box? Do I need to a thicker shim to reduce the play between the clamp and the gear box?


6..... My son had boat in neutral at about 1400 RPMS and put it in reverse and said there was a loud clunk.


7..... I can remove the torsion bolt and check the splines on the U joint to see if they are bent or torsion bolt is Loose? What torque do I reset the torsion bolt at - 60 lbs - others say 90 lbs? How do I reduce the play between the main shaft gear and the gear in the box? Would back lash be an issue if its just the main shaft gear play issue? And will 20w40 oil help reduce the clatter and wear?


8.... I have reviewed my 270 stern drive manual but does not address these specific issues. Your thoughts and suggestions please.


1..... PDS = Primary Drive Shaft. In other words... PDS means Primary Drive Shaft.


2... possibly excessive back-lash due to incorrect shim control.
There are three areas of shim control that affect the gear pattern.
...main drive gear bearing box
...upper driven gear bearing
...lower driven gear bearing


3... the back-to-back bearings (bearing box) are to be set using a rolling torque value. The rolling torque value (275 transmission) is shim controlled.
see your OEM work shop or service manual for the specs.


4.... since the transmission/lower unit can be used for either a LH or RH prop, there is no FWD or REV gear. These are the two driven gears.


5... by reducing the shim value, you would bring the "drive" gear closer to the two "driven" gears.
However, (and only when set up correctly) what you remove from the AFT side of the bearing box collar, must also be added to the FWD side of the bearing box collar.

6.... that would have been the slack in the reverse latch unit.

7.... this gets rather technical. It would be best to read the OEM work shop or service manual, or take it to someone with extensive Hypoid gear experience.
As for the gear oil, your lower unit has a slinger pump in it. Heavy gear oil may damage the slinger pump impeller drive pins.
30W engine oil in cold water....... 40W engine oil in warm water, such as in Florida.

8.... NO Clymers and NO Seloc ..... OEM only.


.
 
Re: # 6 1400 rpm shifts are not recommended and when done result in loud noises.... and reduced tranny life. Normal shifting done @ 650.
 
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