Volvo Pentax SX-M forward gear issue

Kent0

Recruit
Joined
Jul 5, 2016
Messages
2
Hello,
I'm thinking my forward gear cone clutch socket is worn which would require a new gear set since it engages to the back of the gear but I want a second opinion.

The boat is a 2006 stingray 180rx so the drive is likely 2006 also. This is the 7th summer I have owned the boat. I did notice the last couple of times at WOT the RPMs were a couple hundred higher but did not think anything of it. Then last weekend after shifting into forward it would not engage unless I reved it to about 1500rpms and then went in gear with a loud clunk. Reverse works fine. The fluid level was fine. I drained it and there were no shavings. The cable is fine. I removed the shifter and if I move the cone with my fingers, reverse locks good but forward seems to slip some and then lock sometimes.
 

Poco2

Cadet
Joined
May 27, 2011
Messages
18
I am having the same problem with my 2006 sx-m on a 5.0 GXI. Exact same symptom with shifter removed. My conclusion is the cone clutch is worn out. I have around 400 hours which seems like it shouldn't fail that soon. I believe you can replace the cone clutch without replacing the gear set. If designed correctly the clutch should wear not the gear. The forward surface of the clutch is imersed in oil so I don't see how it could ever wear out. How many hours on your drive?
 

4now04

Seaman
Joined
Sep 25, 2010
Messages
53
Look closely at the shift cable adjustment first. My DP-SM did not want to go into reverse last fall. I looked into the outdrive over the winter. The cone portion of the clutch can be changed, but the manual recommends replacing the 3 gears and cone as a set. I readjusted mine this spring and it has been fine. This drive has over 800 hours on it. The '95 SX drive on the previous boat had over 2100 hours without ever being disassembled.
 

billbayliner

Chief Petty Officer
Joined
Jun 30, 2006
Messages
553
You have something out of adjustment. These clutch assemblies do not just wear out. They will glaze up (They hate dino oil and thus should always use fully synthetic). Engine RPM is absolutely critical for quick engagement. Did you take the shift assembly apart? If so, is the shift shoe facing the proper way? The cups of the clutch is part of the driven gears and you better know what you are doing to tear the upper down.
 

Kent0

Recruit
Joined
Jul 5, 2016
Messages
2
I think all my notifications went to spam because I am just now seeing the replies.

I'm not sure how many hours are on my drive but I replaced the cone and shifting shoe and it is working fine now! I had to replace the shifting shoe because the cone had been redesigned and will only work with the newly designed shifting shoe. I measured the new cone and the old one and the measurements are identical, so not sure how it was worn out unless it was glazed up as mentioned. The factory service manual doesn't even tell you how to tell if it is worn, just how to replace it. As for the gear oil, I was thinking I had full synthetic in it before but don't remember. I do have full synthetic in it now.
 
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