How to change gearbox oil?

[Rivers & creeks]

We have a PRM gearbox on a Thornycroft 230 (75hp). The gearbox oil hasn't been changed for at least four years and probably much longer. The box seems to have a nut on the top, I assume I take that off and vacuum suck the oil out. Any idea what oil it should have? I won't be able to get every drop out so does it matter if some old oil is left in? Could it be incompatible with the new stuff? And how full should it be?

Thanks for your help, we are completely new to diesel engine maintenance and the yard have quoted £100 plus the oil to do the change.

 

[sailorman]

We have a PRM gearbox on a Thornycroft 230 (75hp). The gearbox oil hasn't been changed for at least four years and probably much longer. The box seems to have a nut on the top, I assume I take that off and vacuum suck the oil out. Any idea what oil it should have? I won't be able to get every drop out so does it matter if some old oil is left in? Could it be incompatible with the new stuff? And how full should it be?

Thanks for your help, we are completely new to diesel engine maintenance and the yard have quoted £100 plus the oil to do the change.

Try the Percy Riley Motors web site
http://www.prm-marine.com/trolling_valve.php

the remnants of the once famous Riley cars
there will be a drain plug on the underside

 

[VicS]

You know what they say, RT*M

Link to * Manual :-

http://www.prm-marine.com/images/owners_handbook.pdf

£100 ... its called having a larf!

 

[Jim@sea]

EP 90 Gear Oil. I only suggest this as when the Thornycroft was designed they had not even dreamed of putting engine oil in gearboxes like we do today. EP stands for Extreme Pressure, they also did EP 80, and EP 140. Castrol was the best brand and a half pint tin cost 1 shilling and eleven pence halfpenny. (I seem to remember)

 

[sailorman]

EP 90 Gear Oil. I only suggest this as when the Thornycroft was designed they had not even dreamed of putting engine oil in gearboxes like we do today. EP stands for Extreme Pressure, they also did EP 80, and EP 140. Castrol was the best brand and a half pint tin cost 1 shilling and eleven pence halfpenny. (I seem to remember)

PRM hydraulic box's are engine oil, read the download

 

[Rivers & creeks]

What type Roger? I read the download but couldn't see. And mineral or synthetic?

 

[VicS]

Some more manuals at http://www.motoren.ath.cx/menus/prm.php

Should tell you where to locate the drain plug!

 

[sailorman]

What type Roger? I read the download but couldn't see. And mineral or synthetic?

15>40
i have the PRM 150

is yours the 150 or 260
details on my link #2

 

[Mr Cassandra]

I am very interested in the correct technical answer to this post,as I have a hurst gearbox and I am unsure what oil to use

 

[sailorman]

I am very interested in the correct technical answer to this post,as I have a hurst gearbox and I am unsure what oil to use

do a web search on your box

 

[westhinder]

I am very interested in the correct technical answer to this post,as I have a hurst gearbox and I am unsure what oil to use

A Hurth 50 uses Automatic Transmission Fluid.

 

[VicS]

I am very interested in the correct technical answer to this post,as I have a hurst gearbox and I am unsure what oil to use

The correct answer to the original post is that the PMR gearboxes use engine oil. The exact grades suitable depend on the ambient temPerature and are given in the owners manual.

Hurth HBW gearboxes use automatic transmission fluid (ATF)