Need a little help here. I picked up a 2003 25 HP ProDrive that has a Curtis lower unit. Doesn't appear to be any oil in the lower unit. Nothing comes out when
There's a pipe plug near the prop (I'm assuming this is the drain plug), and one in the tower that leads to a second plug inside, in what Curtis calls the input cap. I think this might be the fill plug. No other plugs I can see.
How do I add oil to this unit? How much oil should I expect to add?
Hoping someone can give me some info on this.

man, if I remember right, I would screw my outboard lower unit oil pump into the lower screw and pump 90 wt gear oil into the lower unit till it came out the top plug. just like u would do on a outboard lower unit.

there may be a grease zerk on the top part of the lower unit behind a plug that needs grease every now and then.

been a while. lol

I do know if u all prodrive at 337-299-0038 and ask them, they will tell you what u need to do.

Animal, thanks for the reply.

No zerk in the tower, I know my 32 has one hiding behind the pipe plug. There is another pipe plug where the zerk normally sits.

Travis at PD has been great with info, I was hoping I might be able to get this lubed tonight.

No. No zerk. Like I said, there is a pipe plug behind the pipe plug where the zerk is on my other PD.

Got word from the folks at PD, that plug is the top fill hole. Gon' take a lot of oil!!

Perfect, 50. Thanks very much!

Shooter this is the same lower I had on my 07. Is is still to this day the fastest lower that PD ever cam out with. Couple thing to check and consider.

1) You are suppose to fill from the bottom and watch for it to come out of the top hole. I didn't have a setup to do it, so I would put the oil from the top, when it would look full, I would rotate the prop by hand, thus allowing the oil to pass through the gears into the lower housing. Keep repeating this until oil level is full. Or if you have a setup, fill from bottom until it comes out the top.

2) those lower units came with the 2 seal propnut. It was prone to leak. I contacted PD years ago when the lower was changed to the grease filled and was told that they had a newer 3 seal prop nut. PD swapped out for free. Before you get started and have to drain all tat shit, check to see of you have 3 seals on the prop nut. if not, get the newer one from PD.

3) the earlier PD lowers has a vent. It was basically a threaded hole in the spline adapter in the lower that would allow any pressure that would build up to vent out the top towards the clutch. Well when the lower seal would give out and allow water to enter, the oil, Milky in color, would pour out near the clutch. PD realized their scrwed up and have sealed off that vent. I took mine and installed a brass plug that prevented this from happening. No issues after that.

4) the bottom plug is for draining. If at any time you drain the oil, it will take a while. I usually take a milk jug, cut the top and place it under there. Leave and go do other shit and come back to it. Also, you can put fresh oil in it, start it up, engage the clutch for a sec and kill it. If you drain the oil, it will look "frothy". Its still very good, just stirred up from the prop shaft.

5) if you do indeed blow a seal and get il in there, I found the best way to clean it is add oil, run it out of water with prop engaged to stir it around. then drain. repeat if necessary.


That lower is a great unit and will last as long as you. I had my origional Briggs on it and still had it when I made the Kawasaki swap. Some will bash it because they didn't like the oil issues, but little did they know, it was just simply a plug at the top ($2 from local hardwars store) and a new prop nut with 3 seals which was free from PD that would fix the problem.

Banned - thanks, man. Very helpful.
I filled my lower yesterday and ran it out of the water. Had to drill out the top plug, it was frozen in place. Pumped oil in from the bottom and plugged it when it ran out of the top. Just like it's spose to.
Great to hear about the design performance.

The only thing left and the problem involved is to make sure you lower has the plug in it. BUT..... you have to pull the power head in order to pull the lower to see. But that can be done at a later date. If you don't have oil come you through the tower near the clutch, then the previous owner may have already plugged it. But you'll be able to see that right away. This is an old pic but shows where you need to install the plug. Now the plug needs to be an allen head or square hear. Because if I remember, a normal socket head bolt will impede the spline adapter from sliding over it. Youll know in a hurry if you bust a lower seal cuz the oil will be pouring out the top of that sucker. Also its good to get one of Prestons weed cutters. It held grass and shit from wrapping up and tearing the lower seals which could let water in.

IMAG0059_zpsb46a5dc8.jpg

Wilson - I think that ship has sailed. I gave up and made my own skeg from pics that had been posted here. Might think about doing the same if you have the resources, wasn't that hard.

pd has weed cutters over there. supposed to work well. ask them about it.