PV: - Diff and gearbox oil recommendations

WSU303 · Jan 12th, 2021, 12:56

Hi all,

I'm reading various things about oil for the gearbox and rear axle in my PV544. Some times I read 20w50 for the gearbox, other times it's SAE 80/90. What do others use?

It's a 1962 PV with a B18 engine (Zenith carb). I'm in the UK.

Rear axle should be EP90, GL4, hypoid, or...?

Cheers,
Chris.

Army · Jan 23rd, 2021, 09:25

My advice is to choose a brand and then use their oil advice.

Here in Holland / Benelux countries a company called Kroon Oil make a nice range of oils for classic vehicles.

If I were living in the UK I'd probably be using Castrol classic oils as there they are easier to find than Kroon (whereas here Kroon is easier to find)

WSU303 · Jan 23rd, 2021, 20:40

Thanks Army!

I was confused when the workshop book mentioned SAE 30 oil, but it looks like this was a misprint, because later in the book it says SAE 80, which is more like what I expected.

In the end I've gone for Morris SAE 80 GL4 for the gearbox, and EP 80/90 Hypoid GL4 for the (Spicer) diff. Morris do a good range for classics.

I also spotted some threads on here where someone was advising GL5 oil - in my experience with older Citroens, this is the wrong advice, because GL5 attacks bronze and sintered bushes. GL4 is the only safe formulation for older gearboxes.

All sorted now anyway

142 Guy · Jan 23rd, 2021, 21:14

Your choices should work just fine.

Some of the confusion maybe related to the type of oil. If referring to SAE 30 the service manual likely meant 'motor oil'. When referring to SAE 80 it definitely would have been 'gear oil'. For the M40, Volvo specifies SAE 80 or SAE 90 gear oil (above 30 C) or SAE 30 motor oil. SAE 30 motor oil and SAE 80 gear oil are very similar in viscosity at 20 C.

The Volvo recommendation for non limited slip differentials would be SAE 80 gear oil.

You are semi correct about the GL-4 vs GL-5 designation. A lot of GL-5 oils use sulphur based additives which are not brass friendly. However, not all GL-5 oils use sulphur based additives. Also, modern transmissions typically use brass synchronizing rings so it is not just 'older gearboxes' that you have to be concerned about.

Jan 12th, 2021, 12:56	#1
WSU303 New Member Last Online: Jan 5th, 2022 09:31 Join Date: Jan 2021 Location: Cheshire	Diff and gearbox oil recommendations Hi all, I'm reading various things about oil for the gearbox and rear axle in my PV544. Some times I read 20w50 for the gearbox, other times it's SAE 80/90. What do others use? It's a 1962 PV with a B18 engine (Zenith carb). I'm in the UK. Rear axle should be EP90, GL4, hypoid, or...? Cheers, Chris.

Jan 23rd, 2021, 09:25	#2
Army marches on his stomach Last Online: Feb 11th, 2022 03:15 Join Date: Jan 2018 Location: Somewhere in the Netherlands	My advice is to choose a brand and then use their oil advice. Here in Holland / Benelux countries a company called Kroon Oil make a nice range of oils for classic vehicles. If I were living in the UK I'd probably be using Castrol classic oils as there they are easier to find than Kroon (whereas here Kroon is easier to find) __________________ 1961 Volvo PV544 the quick and easy in between project(!) 1981 Mercedes 300D <=> 230 diesel to petrol conversion project 1965 Series 2a Station Wagon mega build 1992 Mercedes 190E The car that works!

Jan 23rd, 2021, 20:40	#3
WSU303 New Member Last Online: Jan 5th, 2022 09:31 Join Date: Jan 2021 Location: Cheshire	Thanks Army! I was confused when the workshop book mentioned SAE 30 oil, but it looks like this was a misprint, because later in the book it says SAE 80, which is more like what I expected. In the end I've gone for Morris SAE 80 GL4 for the gearbox, and EP 80/90 Hypoid GL4 for the (Spicer) diff. Morris do a good range for classics. I also spotted some threads on here where someone was advising GL5 oil - in my experience with older Citroens, this is the wrong advice, because GL5 attacks bronze and sintered bushes. GL4 is the only safe formulation for older gearboxes. All sorted now anyway

Jan 23rd, 2021, 21:14	#4
142 Guy Master Member Last Online: Yesterday 16:19 Join Date: Jul 2020 Location: Saskatchewan, Canada	Your choices should work just fine. Some of the confusion maybe related to the type of oil. If referring to SAE 30 the service manual likely meant 'motor oil'. When referring to SAE 80 it definitely would have been 'gear oil'. For the M40, Volvo specifies SAE 80 or SAE 90 gear oil (above 30 C) or SAE 30 motor oil. SAE 30 motor oil and SAE 80 gear oil are very similar in viscosity at 20 C. The Volvo recommendation for non limited slip differentials would be SAE 80 gear oil. You are semi correct about the GL-4 vs GL-5 designation. A lot of GL-5 oils use sulphur based additives which are not brass friendly. However, not all GL-5 oils use sulphur based additives. Also, modern transmissions typically use brass synchronizing rings so it is not just 'older gearboxes' that you have to be concerned about.

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