Oil for PRM120

[Bobbybass]

Hi.. just gave my engine its first service.

 

Was going to pump out the PRM 120 and fill with the same oil as the engine.

 

Removing the gearbox dip stick I found it full of a red fluid..rather like auto gearbox fluid ,?.

 

Is that correct..?.

 

Thanks.

[cuthound]

8 minutes ago, Bobbybass said:

Hi.. just gave my engine its first service.

 

Was going to pump out the PRM 120 and fill with the same oil as the engine.

 

Removing the gearbox dip stick I found it full of a red fluid..rather like auto gearbox fluid ,?.

 

Is that correct..?.

 

Thanks.

 

Yes, the PRM 120 uses ATF, not engine oil. However the PRM150 and above use engine oil.

[Guest]

https://www.prm-newage.com/help-centre-marine

From the above " A mechanical gearbox (PRM 60, 80, 90, 120 or 125) must use automatic transmission fluid (ATF) Dextron II or III"

[Boater Sam]

8 minutes ago, Bobbybass said:

Hi.. just gave my engine its first service.

 

Was going to pump out the PRM 120 and fill with the same oil as the engine.

 

Removing the gearbox dip stick I found it full of a red fluid..rather like auto gearbox fluid ,?.

 

Is that correct..?.

 

Thanks.

Auto gearbox fluid is correct for PRM mechanical boxes, 120,    engine oil, non synthetic for hydraulic boxes 150 and up.

[Guest]

2 minutes ago, Boater Sam said:

Auto gearbox fluid is correct for PRM mechanical boxes, 120,    engine oil, non synthetic for hydraulic boxes 150 and up.

Yes, none of that sympathetic stuff in my 150. Stops the clutches clamping properly, according to the manufacturers anyway. 

[Bobbybass]

That being the case .... With my previous larger PRM gearbox that took engine oil..I changed it at about 500 hours.

 

As this is ATF does that mean less changes ?.

After all...you very rarely change ATF fluid on a car...

[nbfiresprite]

15 hours ago, Boater Sam said:

Auto gearbox fluid is correct for PRM mechanical boxes, 120,    engine oil, non synthetic for hydraulic boxes 150 and up.

That depend on which PRM120 manual you look at. My own clearly states engine oil, But then it is a 20 year gearbox. According to Newage they change the oil spec about 14 years back. Newage told me to remove all traces of engine oil before replacing with ep90.

[Tony Brooks]

10 minutes ago, nbfiresprite said:

That depend on which PRM120 manual you look at. My own clearly states engine oil, But then it is a 20 year gearbox. According to Newage they change the oil spec about 14 years back. Newage told me to remove all traces of engine oil before replacing with ep90.

EP90 - that is not ATF, it is at the viscous end of gear oil. I have never heard of PRM specifying gear oil, that is a Lister gearbox thing.

 

 

[Bobbybass]

Heck...now I'm confused..

 

Engine oil....ATF...now a Hypoid ??.

 

Plus...I still don't know the change intervals..

 

The plot thickens.. ( the oil does anyway ?)

Edited September 6, 2019 by Bobbybass
Updated information

[Bobbybass]

Just spoke to Beta.

 

It should be ONLY ....ATF Dextron 2 or 3.

Service interval is up to you..but as it only holds 0.3 litre..it may as well be done every year.

 

Thanks everyone..

 

 

[rgreg]

1 hour ago, nbfiresprite said:

That depend on which PRM120 manual you look at. My own clearly states engine oil, But then it is a 20 year gearbox. According to Newage they change the oil spec about 14 years back. Newage told me to remove all traces of engine oil before replacing with ep90.

Indeed: I called PRM with this query many years ago and was advised to "put in whatever oil you put in your engine". I have continued to do this and 17 years on it's still going strong. I guess there must be a reason for the change in advice to ATF.

[Boater Sam]

The usual reason for gear manufacturers to change spec to ATF is a temperature thing, ATF will not breakdown at extreme temperatures. We had this with Land Rover gearboxes, they went from gear oil to ATF many years ago to increase there life under extreme conditions.

Do not use any EP or Hypoid oils in anything unless specifically told to, they dissolve certain bronze alloys. 

[Taslim]

7 hours ago, Boater Sam said:

they dissolve certain bronze alloys. 

Thank's for that.

[Boater Sam]

7 hours ago, Boater Sam said:

The usual reason for gear manufacturers to change spec to ATF is a temperature thing, ATF will not breakdown at extreme temperatures. We had this with Land Rover gearboxes, they went from gear oil to ATF many years ago to increase there life under extreme conditions.

Do not use any EP or Hypoid oils in anything unless specifically told to, they dissolve certain bronze alloys. 

And thinking further, all the PRM hydraulic gearboxes, 150 160 260 280 500 etc are recommended to have an oil cooler inline, Not so the mechanical ones. This could be why PRM changed the spec of the correct lubrication, perhaps they realised that they would run over a safe temperature for straight mineral oil. And synthetic as we have established causes clutch slip in these boxes.

[nbfiresprite]

9 hours ago, Tony Brooks said:

EP90 - that is not ATF, it is at the viscous end of gear oil. I have never heard of PRM specifying gear oil, that is a Lister gearbox thing.

 

 

That's what I was told at the time, I made a note in the manual, but then the lady I spoke to may have given me the wrong info. The gearbox has done over 10000 hours with ep90 with no problems, oil changed at the same time as the engine.

[Guest]

14 minutes ago, Boater Sam said:

And thinking further, all the PRM hydraulic gearboxes, 150 160 260 280 500 etc are recommended to have an oil cooler inline, Not so the mechanical ones. This could be why PRM changed the spec of the correct lubrication, perhaps they realised that they would run over a safe temperature for straight mineral oil. And synthetic as we have established causes clutch slip in these boxes.

Interesting thought. I seem to recall reading that some bikes have had problems with wet clutches and synthetic oils, but can't remember the finer details now. 

[arcsyst]

On 06/09/2019 at 18:16, nbfiresprite said:

That's what I was told at the time, I made a note in the manual, but then the lady I spoke to may have given me the wrong info. The gearbox has done over 10000 hours with ep90 with no problems, oil changed at the same time as the engine.

I had problems with clutch slip with ATF and experimented with various oils finally settling on Comma gear oil EP80W-90 GL-4 which gave the best performance and lowest noise (straight engine oil worked but made the gearbox noisy). Two years and 1000 hours later it's still fine.

[Tracy D'arth]

Good to know, generally it is frowned on to use gear oil.

 

Beware of hypoid though, there are bronze parts in the gearbox that will object.

[LadyG]

On 06/09/2019 at 10:43, rgreg said:

Indeed: I called PRM with this query many years ago and was advised to "put in whatever oil you put in your engine". I have continued to do this and 17 years on it's still going strong. I guess there must be a reason for the change in advice to ATF.

I believe catastrophic failures, advise now is Dexron2 if that was previously used.

I spoke to Newgate, no mention of flushing to remove engine oil.

On 05/09/2019 at 17:36, Bobbybass said:

Hi.. just gave my engine its first service.

 

Was going to pump out the PRM 120 and fill with the same oil as the engine.

 

Removing the gearbox dip stick I found it full of a red fluid..rather like auto gearbox fluid ,?.

 

Is that correct..?.

 

Thanks.

Yes, Dextron2 is red.

Automatic Transmission Fluid.

Edited August 21, 2020 by LadyG

[LadyG]

On 06/09/2019 at 08:25, Bobbybass said:

That being the case .... With my previous larger PRM gearbox that took engine oil..I changed it at about 500 hours.

 

As this is ATF does that mean less changes ?.

After all...you very rarely change ATF fluid on a car...

PRM120 takes .8l, and 5l costs £17.99

Take manufacturer's recommendation.

 

Edited August 22, 2020 by LadyG

[LadyG]

On 05/09/2019 at 17:36, Bobbybass said:

Hi.. just gave my engine its first service.

 

Was going to pump out the PRM 120 and fill with the same oil as the engine.

 

Removing the gearbox dip stick I found it full of a red fluid..rather like auto gearbox fluid ,?.

 

Is that correct..?.

 

Thanks.

Btw, I had the gearbox pumped out then the sump plug removed, it's magnetic, so if silver shards are seen, be worried, mine was just fine grey-black softish residue [after maybe 15 years, so no worries in spite of previous lack of maintenance.

We removed .4L of grey fluid and put in .8l red Decxron2. It will be changed annually from now on, I have 4L left, 5 years supply.

Edited August 23, 2020 by LadyG

[NBDensie]

From memory the manufacturer's recommendations for the PRM120 were changed a few years ago.  When I bought my boat in 2006 engine oil was recommended and that is all I have ever used..  The gearbox oil is changed every 1000 hours and has always been completely clean.

[Tracy D'arth]

ATF has a better heat rating than engine oil, PRM120 will likely not have an oil cooler attached, so stay with Auto Transmission Fluid.

[Machpoint005]

Does a boat's gearbox get especially hot? It's not something I have ever noticed.

[Tony Brooks]

1 hour ago, Machpoint005 said:

Does a boat's gearbox get especially hot? It's not something I have ever noticed.

Hydraulic ones will apart from Lister LH150 because they are pressurising oil all the time they are running in gear. That's why they tend to have oil coolers. Mechanical ones tend to use ribbed alloy cases to help dissipate the heat produced from friction and throwing oil about.