Talk Morgan Forums Morgan Sports Cars Morgan Three Wheeler & Super 3 Bevel Box oil change

I'd be out a ton of money and have a very angry wife if not for this forum and some knowledgeable (Chris and Stephen) local folks as well! Much appreciated everyone!

I use Royal Purple 75-140wt.

I have a 2017 as well and believe Morgan long stopped putting the additive in before your year so you should be fine. There is a big thread on gear oil and quieting the bevel down. I believe it was the redline was the product where people had positive results with.


By the way do yourself a couple favors and get a small lift. I purchased an EZ Car Lift and it works like a charm and visit Phil’s website and Emil’s (custom Morgan). Most importantly enjoy your awesome machine.

Yes, 'Red Line 58204 Heavy Shock Proof Gear Oil' is the stuff. It won't silence a really noisy bevel box but it is about as good as you can get.

Not sure about the sizing of the front seal on the input shaft but the finish wasn't too bad on mine, not chuck marks like the Centa had. The standard seal is a Nitrile type and it will be running pretty close to it's upper range, or over it. There is a Viton seal available in the same size that has a much higher temperature operating limit. I haven't heard of any of these leaking since replacement.

I probably am doing an overkill with the BB oil changes but 330cc of oil every 3000 (maybe 6000?) miles isn't a big cost compared to the BB.

Originally MMC didn't specify any BB oil change interval but (I think) around 2015 they added it to the 3,000 mile/annual service schedule.

In true MMC fashion they didn't highlight this to some (all?) dealers so it's worth asking for the BB oil change at service time if you're not doing it yourself.

This is what I use in mine. Description from their site

Redline 80W250 GL-5 GEAR OIL

Recommended for SAE 250 or where SAE 140 does not provide adequate protection
Alternative to Red Line Heavy ShockProof® in problem Nitro Drag Race Vehicles
Can be used in Model A, Model T vehicles and Antique/Classic cars calling for 600W
Reduces noise levels in Morgan 3 Wheeler bevel boxes
Excellent for off road use where SAE 250 is required

After using Millers EP140 for about 12,000 miles I tried the Redline 80W/250 and actually found it worse overall. The BB noise was slightly louder but over a slightly narrower rev range.

It's wasn't enough of a difference for me to swap back straight away but I went back to EP140 at the next BB oil change.

It's also worth noting that the Redline 80W250 isn't available in the UK so has to be ordered from the USA with a minimum quantity of 1 US gallon (3.785 litres).

A few of us acquired some of the 80W250 GL-5 Redline from the USA to try and found it wasn't quite as good as the Redline Heavy Shockproof 75W/140, although they claim it reduces the noise levels in M3W bevel box......compared to what?

I read through the owners manual over the weekend that came with the M3W. The only thing I could find about the bevel box was a recommendation that it should be serviced when the oil is changed. Nothing else, zip, zero!

I do plan to get a lift at some point, thankfully I have a friend with a small garage shop down the street. He's going to let me make use of his lift whenever it not being used.