Borg-Warner Stuck in Forward Gear

[Brewgyver]

Originally Posted by skipper53

On an A4, if the engine is shut down while in forward, it is nearly impossible to shift back to neutral before restarting the engine. Try starting the engine in forward gear (if no neutral safety switch) and it may shift easily.

Then, shut the engine down while in neutral next time.

That works for me.

The Universal Atomic 4 has an integral reversing gear, with direct mechanical operation. It's basically just a planetarty gear train to achieve neutral and reverse. All BW Velvet Drives are hydraulically actuated, very different animal.

[Brewgyver]

Originally Posted by jordanbigel

(snip)
1- before the shifter was stuck in Fwd, shifting operated normally both with the engine on, and, with the engine off
2- after the shifter was stuck in Fwd, and I slammed the shifter level with my hand to get it back into neutral, everything worked fine (by which I mean I was able to shift easily and normally between neutral and fwd/reverse both with the engine on, and with the engine off)

Also, before last week, I checked the trans oil level and verified the shifter movement both with the engine on and off - smooth as silk.
(snip)

Therefore, I am interested to learn about what could cause this issue which is not related to a sticky or rusty shifter cable (which I do not have)?

The Velvet Drive transmissions are hydraulically operated. With the engine running, the Drive's integral pump raises the pressure of the oil to 110-150 psi. Rotating the selector valve to the Forward position directs the pressurized oil to the forward clutch piston, which in turn compresses the forward clutch plates together. Rotating the selector to Reverse directs pressurized oil to the Reverse clutch piston, compressing the reverse clutch plates together. When the selector moves to Neutral from either Forward or Reverse, the piston pressure is vented, and the clutch springs push the pistons back into their non-extended position.

So, when the engine isn't running, the VD pump is not pumping, and neither the Forward nor the Reverse clutches are engaged. So rotating the shift selector valve with the engine off doesn't shift the drive at all.

So, if the shift cable is not sticking, I would look at the actual shift controller. It's possible that some foreign object fell into a position that blocked the lever that actually pushes and pulls the end of the shift cable. It's better than a 50/50 chance that your's is setup to Pull the cable to engage Forward, and to Push it to engage Reverse. The foreign object scenario I'm suggesting would explain the heretofore one-time occurrence of the problem, with the object being dislodged whet you had to force the control to shift out of Forward.

Another possibility could be metal shavings or the like actually circulating insied the Velvet Drive. Hopefully that's not the case, but if you can't find any other cause, you'd better check it out. Drain the oil into a bucket and drag a magnet through it, for starters.

[jordanbigel]

Originally Posted by Brewgyver

So, when the engine isn't running, the VD pump is not pumping, and neither the Forward nor the Reverse clutches are engaged. So rotating the shift selector valve with the engine off doesn't shift the drive at all.

...

Another possibility could be metal shavings or the like actually circulating insied the Velvet Drive. Hopefully that's not the case, but if you can't find any other cause, you'd better check it out. Drain the oil into a bucket and drag a magnet through it, for starters.

Thanks! Great info - and yeah, I assumed that when operating the shift lever with the engine off, no hydraulic pressure was present, the goal was simply to verify the smooth operation of the cable.

I'm hoping your foreign matter theory is right. And I will definitely do the magnet test and see if any metal shavings are in there! Thanks again.

[primerman]

SV and Jordan thanks for the post. The identical situation happen to me last weekend. New boat (to me), 15 hr trip, got to new berth and stuck in forward. I thought it was the old controller on the binnacle, took that apart last night, it's fine. Today will be taking the morse cable off the 71C and testing. Did I read correctly that it is challenging to shift into neutral when the 4.236 is off? Also, if it is the shift control piston, I am unclear to fix if I buy a rebuild kit or an entire new one? Please advise.

[Boatyarddog]

Originally Posted by primerman

SV and Jordan thanks for the post. The identical situation happen to me last weekend. New boat (to me), 15 hr trip, got to new berth and stuck in forward. I thought it was the old controller on the binnacle, took that apart last night, it's fine. Today will be taking the morse cable off the 71C and testing. Did I read correctly that it is challenging to shift into neutral when the 4.236 is off? Also, if it is the shift control piston, I am unclear to fix if I buy a rebuild kit or an entire new one? Please advise.

Remove and inspect for scoring.
The video explains some things to look for.
There's also a phone number you could call and do some research.
SV Cloud Duster

[jordanbigel]

In my case, the problem seems to have been a one-off, although I have not done another 15+ hour motorboat ride since then, but I have used the motor for an hour or two on 3 occasions since and had no trouble. But, on the day when this happened, and I couldn't get it out of Fwd, I shut the engine off and still could not get it out of gear without applying a massive shock force to the level, which got it back to N and then after restarting the engine, it worked fine. Hope this info helps. I still really have no idea, but I am planning to get a spare control piston to keep on board. Good luck primerman.

[idpnd]

I had this issue on my jet drive dingy, only it wasn't really an issue, since I could use the the "bucket" on the drive as gears by directing the jet drive output, even though I suspect thre may have been some slippage at the top end. It had run out of oil and there was water in it. I ran it in this format for a while, before I elected to put oil in again,

Now the gears have started working again, but the transmission is slipping massively in forward,

The transmission is corroded into one rusty red lump, I cannot even see half of the bolts, and this boat is due for remotorization anyaway,, I'n definitely not overhauling this dinosaur trash technology with forumloads of issues wherever I look!

So, and I know this might prove controversial, I'd like to make this drive lock in forward gear.

Any ideas?