Running PRM 150 on power steering fluid

[Joe the plumber]

The PRM 150 gearbox on our boat has an intermittent metallic 'ticking' sound when in gear. In neutral, it disappears. I thought for a start it was something around the prop flapping about, but there's nothing there. A new genuine Beta driveplate was fitted to the B43 last October, so I've discounted that.

 

Chatting about it with an RCR chap on their Crick stand over the weekend, he said it may be play in the layshaft and suggested running the gearbox on power steering fluid (PSF) instead of the usual 15W40 engine oil. I've only just changed the oil in it (there were no visible particles in it) but he assured me the box was originally designed for PSF and as an extreme pressure oil, it could sort the noise.

 

Given the PRM site says to use 15W40 oil and I can find nothing anywhere else about putting in PSF, is it something anyone else has tried, and if so, with what outcome please?

 

The box is well out of warranty and if there is wear, I'm dubious about different oil sorting it, but the RCR chaps aren't idiots, so I'm tempted to try it. As a Gold RCR member, the box is also covered by them if it expires.

 

Thanks as always for any thoughts.

[RLWP]

I wouldn't

 

Richard

[Joe the plumber]

Thanks Richard. Could you elaborate please?

[RLWP]

I have heard your description, I have no idea what's going on inside your gearbox. If I had to guess (guess), I'd say your drive plates are failing. If so, why would a thinner more expensive oil help? Otherwise, I have no idea what 'play in the lay shaft' means, or why thinner oil could make a difference

 

The manufacturer recommends engine oil

 

Richard

[zenataomm]

What would be the chances of RCR saying you invalidated your cover with them because you hadn't followed the maker's instructions?

[boathunter]

I know someone who ran a fiat for thousands of miles with jack oil instead of engine oil as that was all he had. It was fine. This is not advice.

[IDS]

Why not talk to the PRM-Newage technical desk, I assume they will have one, their web site has contact details

[Joe the plumber]

Thanks folks. I thought it was an odd suggestion. I'll have a chat with PRM, but I'm now much more inclined to leave the specified oil in there and see how it goes.

[steamraiser2]

Richard is right. Your gearbox is in need of TLC and changing the oil will not help.

[Martin Megson]

The following extract from the PRM manual clearly states engine oil.

 

[Steve@FiddlersGreen]

I guess you have already ensured the oil level is correct it's just that your symptom sounds similar to one I experienced when I fitted a new PRM150 a couple of months back, it was resolved by topping up the oil (15/40) to the correct level.

[Joe the plumber]

I changed the oil a month or so back and double checked it was at the right level Steve. it was making the noise before the oil change and carried on afterwards. I'll check it again though, so thanks for the thought.

[Sea Dog]

I changed the oil a month or so back and double checked it was at the right level

I did mine a couple of days ago and, like every other time, double checking was only the start of it! The oil, particularly when new, is so clear and clean that I can never be sure of where the blooming oil level is by looking at that lovely shiny dipstick! I always resort to numerous goes at the stains it makes when laid against kitchen paper, but if anyone has a better idea I'd be keen to learn!

 

However, my PRM150 takes the same 15w40 engine oil as the Beta 43 it's mated to. Some of the Zf alternatives use ATF - not PSF, bit perhaps he has his wires crossed?

[Tony Brooks]

However, my PRM150 takes the same 15w40 engine oil as the Beta 43 it's mated to. Some of the Zf alternatives use ATF - not PSF, bit perhaps he has his wires crossed?

 

And the smaller mechanical PRMs now.

 

 

FWIW I have been running my mechanical Spanish ZF box withe ATF for about 12 years without problem. The manual says straight SAE 30 and on no account use multigrade. I did take advice and the hire company I bought the boat from had put ATF in the box.

 

I understand that for gearboxes that do not get as hot or as dirty as engines ATF may be viewed as a "better" oil - whatever that may mean. Probably better film strength and anti film sheer.

Edited June 1, 2016 by Tony Brooks

[Harpur Hill]

FWIW I used ATF in my 350hp Cobra replica gearbox with no problems.

 

HH

[Neil Smith]

If I remember the first 150 box manuals recommended atf but changed to engine oil soon after without modifying the box, probably as the old delta box the processor to the 150 used it.

 

Neil.

[alan_fincher]

If I remember the first 150 box manuals recommended atf but changed to engine oil soon after without modifying the box, probably as the old delta box the processor to the 150 used it.

 

Neil.

 

Not sure if you mean the Delta used ATF, or that the Delta used engine oil?

 

I had a boat with a Delta until recently, and the manual said ATF.

 

I know PRM have recently started saying ATF for the non hydraulic 120 box, but AFAIK, it is engine oil for all the hydraulic types.

 

My understanding is that the Delta and the 150 are remarkably similar internally.

[X Alan W]

I did mine a couple of days ago and, like every other time, double checking was only the start of it! The oil, particularly when new, is so clear and clean that I can never be sure of where the blooming oil level is by looking at that lovely shiny dipstick! I always resort to numerous goes at the stains it makes when laid against kitchen paper, but if anyone has a better idea I'd be keen to learn!

 

However, my PRM150 takes the same 15w40 engine oil as the Beta 43 it's mated to. Some of the Zf alternatives use ATF - not PSF, bit perhaps he has his wires crossed?

I had a mate who was a tanker driver delivering petrol & diesel to filling stations he used to rub blackboard chalk on the tank dipsticks in the area were the level should be, don't know if it would work by rubbing your clean /dry dipstick at the level marks It showed up really well with diesel

[Sea Dog]

I had a mate who was a tanker driver delivering petrol & diesel to filling stations he used to rub blackboard chalk on the tank dipsticks in the area were the level should be, don't know if it would work by rubbing your clean /dry dipstick at the level marks It showed up really well with diesel

Thanks Alan, interesting thought. I'd be less happy introducing anything foreign into the gearbox, but I can see how a tiny measure of soft stuff in diesel would probably not hurt with a filter or two before anything with tight clearances is met.

[Neil Smith]

I meant the delta used ATF and also the very first 150s.

 

Neil

[alan_fincher]

I meant the delta used ATF and also the very first 150s.

 

Neil

 

I can only say again that our Delta didn't - the manual said to use engine oil.

[paddles up]

The Delta and 150 are nigh on identical internally as Alan says, I would be very surprised if the Delta were ever meant to run on ATF rather than engine oil.

 

Don't get me wrong, it will work, but I've never come across any Newage built hydraulic box that needed ATF as per manufacturers instructions.

[Ray T]

 

I can only say again that our Delta didn't - the manual said to use engine oil.

 

From the Delta workshop manual:

 

 

 

PRM 150 Workshop manual

 

 

 

Had both gear boxes in our boat and never used transmission fluid.

Edited June 2, 2016 by Ray T

[Joe the plumber]

PRM were shut this week but I'll hopefully have a chat with them next week to see if they can help identify what my 150's noise is caused by.

 

I think I'm convinced that putting PSF into it isn't the right idea. If the noise was caused by worn out oil, the new (correctly specified) oil I put in a few weeks back

would have sorted it, which it didn't, and if it's from wear, I've yet to find any liquid additive that can permanently and properly repair worn metal!

 

It's been interesting reading all the replies, so thanks to you all for them so far.

 

I wonder what the RCR chap based his suggestion on though?

[Ray T]

Joe, if your gear box is "busted" I recommend RLWP for repairs. He renewed the oil seals in both the input and output shafts of our 150 earlier this year and I am pleased with his work.

 

http://www.primrose-engineering.co.uk/

Edited June 2, 2016 by Ray T