I have a 95 27' Advantage Victory with a 541 ci EFI 600 HP and a Volvo DP-X drive. I bought the boat two years ago and it only had 6 hrs on a new motor. I'm very happy with it except for one thing. It is extremely difficult to take out of gear. It goes into gear with a clunk but I don't think there is a problem there. I replaced the shift cable right after I got it because it was about 6' too long. Although that helped, I still don't think it's right. It makes maneuvering around docks very interesting. The only it comes out of gear easily is if I happen to have the drive turned all the way to one side or the other.
I have talked to several marine mechanics and most of them don't know enough about this drive to point me in the right direction or solve the problem. I talked to a factory rep at the LA Boat show this year and he said there are shims that go in the shift plate by adding or subtracting them, but I don't know enough to mess with it. Does anyone out there know of a DP-X guru on the west coast and preferably in the Lake Havasu area? Really like to solve this issue before I do damage to it.

Check the shift interrupter under the control box. May need adjustment.

I was told by the mechanic that put my new cable in, that they don't have one. I have a separate throttle and shifter

DPX drives have shift interuptor

IMO problem there or cone clutch or its glazed very badly

Shift cable adjustment and or needs a new one

Volvo highly recommends a syn GL 5 spec 75w -140 for these.

Thanks. I will spend some time looking into this. Shift cable is new. If I don't have a shift interrupter, I'll probably look to having one installed. I took out the shift/throttle assy and could find no evidence of a shift interrupter. On drive oil, I use Lucas M8. Don't know that I've seen the GL5 oil. but will look.

Interrupt is just a small red box in line with the cable. It actuates through push/pull forces and has a small magnetic 2 wire connector that runs to it. They are very sensitive as to position on the cable, as in, if it is near a bend or offset it may affect its operation. Just helped out another fellow DPX owner with this same sort of issue. I relocated mine several years ago and alleviated all associated problems.

As BUP said, it could also be a slipping cone clutch. When they slip and get hot they tend to swell a bit and stick in the cone.

One thing you didnt metion, is what is your set idle speed? If it is idling a bit high, that could be the reason for your into gear "clunk" and also the reason it is difficult to get out.

.My idle speed, which I think is due to EFI, is about 800 to 850 RPM. This seems high to me but that's how it was set up when I bought it.

Idle would seem to be in range. When you move your shifter slightly toward forward or reverse but still in neutral, does the engine idle up another hundred rpm or so?

How is drive oil color? Is it relatively clear or dark and burnt looking? This would be an indication of whether to look inside boat or inside drive

When I put it in gear, I notice no difference in the idle RPM, except when it goes in to gear and the props are turning. I know they are moving a lot of water and sometimes it will even stall. I attribute that problem to the EFI being set up pretty rich. It restarts without a problem. Last time I changed my drive oil was the first time I personally changed it. It was pretty dark and had a strong sulphur smell to it, but no evidence of water or metal etc. I put Lucas M8 in it which is a pretty clear oil. I check it regularly and it has not changed color much if at all. It still looks clear.

Sounds like someone was using Merc High Perf gear oil cause they can get that strong sulpher smell being worn out and overheated. Longtime users of this gear oil on Volvo outdrives seem to glaze the cone clutch overtime. Volvo Penta in their Tech schools warn against using Merc gear oils all the time. also Merc High Perf gear oil is a 80w -90 GL 4 spec. Not even what Volvo recommends especially for the DPX.