Borg Warner 10-13 Slipping

[Eurobanker40]

Hi all
I have a problem on my Borg warner VD 10-13 port gearbox and I'm hoping someone could shed some light on it.
Yesterday I noticed that our speed on the boat was a fair bit less than normal while the rpm was around 1500. I played with the throttle but it appears the gearbox is slipping as I increase the rpm. I'm thinking the clutches are worn but just wanted to check with you guys if it could be anything else causing the issue. It's a definite slip within the gearbox as the prop shaft rpm doesn't increase with the engine rpm above about 1200rpm. The gearbox oil seems to have gone a little darker than it was the last time I checked.

Another thing that has been going around my head is that I often use just 1 engine of the 2 when were cruising around, therefore the gearbox that is stopped is freewheeling in neutral. Could I have possibly damaged the gearbox by doing this?
Any help advice would be appreciated.
Thanks
Jamie

 

[STB]

Get a phototach from Amazon or Harbor Freight or wherever for about $25. It'll come with a long strip or roll of reflective tape. Cut off two small squares. Put one on the shaft just aft of the transmission and one on the main pulley/dampener (not the alternator pulley, not the raw water pulley, etc, as these may have a different radius and therefore different RPM). Put another on the shaft just after of the transmission.

Once you get underway and where you can go steady, start out at idle speed. Measure the RPM with the phototach on the main pulley/dampener. (Take the opportunity to calibrate the tach if you'd like.) Then, do the same on the shaft. Record the approximate throttle setting and both RPMs. Note the ratio between the two (pulley:shaft). Bump the throttle until the /engine pulley/
Is 250 RPM faster and repeat. Do the same at another 250 RPM. Then go in 250 RPM or 500 RPM steps until cruise RPM (not speed).

It is important to measure RPM directly on this pulley, not via the gauges which use an alternator takeboff or auxilliary take-off, etc, which could be off, or the wiring could be bad, or the gauge could be bad or recalibrated.

The ratio you observe should be constant or there is likely slipping. It should also match the transmission's reduction gear ratio, which may begin a tag on the transmission.

Also, make sure you measure a small few times at each location at each throttle setting just to avoid human error. Take a measurement, make sure it is steady, relax for a second, and repeat. Do it maybe 2-4 times for each test.

You can also check reverse in the same way, but that is a different ratio, and you wont go nearly as high RPM. Also, it doesn't seem like your concern.

Unless there is noise, shuddering, or the boat is turning or taling heavy rudder, I'm betting it isnt the transmission but the gauges. So, try to pay attention for noise while cruising, while shifting (at idle), and in reverse. (Dont shift except at idle or very low rpm). It might help to listen from near the engine vs the flybridge.

You can also send the oil out for analysis to look for metal or other signs of wear. That usually only costs a few dollars, e.g. about $20, and takes only 2-3 days.

Edit: Obviously, this is a 2-person exercise: One to drive and one to measure RPM. And, the reflective tape gets put on when everything is turned off at the slip and it may take a dab of acetone, alcohol, or other degreaser to get the reflective tape to stick.

 

[STB]

You could also use an IR thermometer to check temp on the transmission while at cruise.

 

[SoWhat]

Just about every sailboat out there is free wheeling

YOu don't mention engine size or youre cruising speed but manual states freewheeling at slow speeds is OK and for short periods at higher speed. Because the pump is not pushing oil through the cooler you run the risk of overheating. Dark oil is a sigh of overheating.

It certainly sounds like forward clutches are slipping. Typical rebuild costs about $750. It would include clutches, seals, o-rings, and gaskets. You deliver transmission. If you are comfortable pulling a head off the engine then you could rebuild it yourself. It's not a complicated job and parts are available.

Replace your damper plate once transmission is out.

Transmission weighs about 175 lbs. You can remove the reduction gears first to get the weight down. I built a frame and mounted a trolley to hold a ratchet hoist. Made it easy to move transmission back and over. I also replaced 2 bolts with tap end studs so I could reinstall transmission easily without damaging splines.

(Photos available if needed)

 

[catalinajack]

Hi all
I have a problem on my Borg warner VD 10-13 port gearbox and I'm hoping someone could shed some light on it.
Yesterday I noticed that our speed on the boat was a fair bit less than normal while the rpm was around 1500. I played with the throttle but it appears the gearbox is slipping as I increase the rpm. I'm thinking the clutches are worn but just wanted to check with you guys if it could be anything else causing the issue. It's a definite slip within the gearbox as the prop shaft rpm doesn't increase with the engine rpm above about 1200rpm. The gearbox oil seems to have gone a little darker than it was the last time I checked.

Another thing that has been going around my head is that I often use just 1 engine of the 2 when were cruising around, therefore the gearbox that is stopped is freewheeling in neutral. Could I have possibly damaged the gearbox by doing this?
Any help advice would be appreciated.
Thanks
Jamie

The Borg Warner manual clearly states that free-wheeling will not damage the transmission. It is so because the oil pump pumps by means of the shaft turning.

 

[Eurobanker40]

Job done!

Hi all
Just wanted to let you know that I removed the gearbox, took it home and stripped it finding the oil black and the forward clutches well worn as expected.
Clutch plates, seals and gaskets purchased from Lancing Marine cost just over £200.
Replaced, reassembled and refitted and all working perfectly, so well chuffed!
The gearbox is a hell of a weight, nearly killed myself lifting it around.
Cheers
Jamie

 

[jleonard]

Awesome!

What does "chuffed" mean?

 

[Eurobanker40]

Chuffed means pleased/happy!