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SX Hard Shifting 2002 5.0

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427435

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Spent some time working on my son's "new" boat-----a 2002 Larson 210 SEI with a 5.0 GL and an SX Volvo outdrive. My son had been complaining about it being very, very hard to shift from forward back into neutral. I took the cover off the back of the outdrive and the linkage seemed to be correctly adjusted. I disconnected the linkage and all resistance to moving the gear shift control disappeared (as I expected). Checked the oil and it was a 1/2" overfull and blue in color (like many marine oils). I found in the operator's manual that the oil should be a synthetic GL-5 and that the original factory fill should be amber in color. So maybe someone cheaped out and put in the wrong oil.

So off to Fleet Farm for 3 quarts of Mobil 1 75w-90 GL-5 rated gear lube. Changed the oil out and went for a test drive. Shifted much, much better. So I'm thinking the problem is solved-----or am I missing something?? Or was the fact that the level was too high a likely cause??

By the way, the idle is at about 750-800 rpm if the tach is to be trusted.
 
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Re: SX Hard Shifting

The cone clutch type gear engagement relies on thrust/torque (and initial friction) to keep the sliding sleeve engaged with the gear cup.
In order to seperate these two, the thrust must be reduced to a level whereby the sleeve can be released from the cup.
IOW, if the idle speed is too great, the thrust from the propeller (while the hull is at below prop thrust speed) causes the sliding sleeve and gear cup to remain engaged with each other.

Try lowering your low speed rpm to within OEM specs, and see if that improves disengagement!

Mean while, do not force a shift into Neutral.

Does this act the same when coming out of reverse?
 
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Re: SX Hard Shifting

There wasn't a problem shifting out of reverse (and there isn't now with the new oil). What is the idle spec for the engine? I figured 750 rpm in neutral would be pretty close.
 
Re: SX Hard Shifting

I thought it would be best to post this to your thread, rather than respond to your PM.

This is an SX upper drive for the purpose of showing you the sliding sleeve and gear cups.

BTW, I find it more fitting to think of the "Cone Clutch" as the SUM of all parts...... I.E., the double end conical shaped "Sliding Sleeve" (seq #28) and the two driven "Gear Cups" (seq #10). To me, this is what is referred to as a "Cone Clutch" unit.

Upper%20Gear%20Unit%20SX.gif


The three gears (and two respective gear cups) rotate continuously when the engine is running.
The vertical shaft and conical sliding sleeve are stationary (minus the water current moving the prop) at this time.

As the shifter moves the sliding sleeve into contact with either of the selected gear cups, friction is generated.

(Note the steep spiral splines of the vertical shaft (seq #29) that the sleeve glides on! These play an important roll as to what causes the sleeve to further pull itself into the cup! )

This friction against the splines forces the sleeve further into the gear cup until they finally lock up, and rotate 1 to 1.
This is full gear engagement!

To release this "grip" (for lack of a better word), the friction must be reduced....... hence the lower RPM during disengagement.

So, to answer your question regarding oil...... all of these parts are either splash lubricated, and/or lower gear unit pump lubricated, and/or submerged, and/or one way or another, completely lubricated while under power.... if the oil level is correct!

Once in a while debris will burnish the cup, and both must be de-glazed. However, this cannot be done to the coated gear cups that were used in some drives.
 
Re: SX Hard Shifting

I appreciate the info. It would appear that a "slippery" oil or an oil that maintains a film between the sleeve and the splined shaft would make things shift easier. At least that seems to have solved my son's problem.
 
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