Gearbox oil

happy days

happy days

Active Member
Checked the oil in my gearbox 3500s can see the oil in the box, level is below the filling point ie below it overflowing out.Does that need topping up or is it ok? have a slight whine from gearbox. Secondly topping up is it with good quality engine oil. cheers Mick
 
With the car on level ground fill it to the point at which it won't take any more without it running down the side of the box. 20/50 is the correct oil. With the filler plug out, and you looking in there, why would you not top it up?
 
Hi Mick,
An oil that works well in these gearboxes is Millers 'Classic Mini' oil. It's a 20W-50 as Harvey states.
 
Not having ever owned a 3500S, this is something that I have never considered in the past.

I see that the Rover manual gearbox in the 3500S requires 20W-50 engine oil as lubricant as opposed to 80W-90 gear oil. The latter I understand is typical of what is to be found in most manual gearboxes.

In what way are the gearboxes different to allow for such a large difference in viscosity,..ie 20W as opposed to 80W? How does gearbox longevity compare when looking at the Rover box and say a similar box that requires the much heavier gear oil?

I understand that classis minis also use engine oil in the gearbox.. :?

A question for you Harvey,..thanks indeed... :)

Ron.
 
All P6 manual boxes were specified 20/50, the only time I ever put EP90 in them was to cure clutch spin when owners didn't want to pay to have the gearbox removed to cure it. 3500S gearbox oil pumps won't pick up EP90 well, but the pumps don't stop the boxes shredding themselves anyway. Whether EP (Extreme Pressure) would stop the pitting on the teeth that seems to be prevalent on the reverse gears on V8's in particular I don't really know. I wouldn't say 2000/2200 boxes were any more troublesome than other makes that run EP90, and although the 3500S box is troublesome (nice bit of understatement there....) that's nothing to do with the oil used, just the fact that the box isn't up to the job in the first place.
 
happy days said:
would it be better to empty the existing oil and replace all with millers
Click to expand...

Gearboxes are generally left to there own devices for far too long by most owners, I have always made it a policy on purchase to change all fluids (except water :LOL: ) ie motor, box, diff. The gearbox is the one that probably needs the most attention with bits of metal always floating around from either synchros or teeth , I dont know if the manual boxes have a magnetic sump bung....they can be truelly enlightning as to why you should change your gearbox oil on a more regular basis.

Graeme
 
happy days said:
would it be better to empty the existing oil and replace all with millers
Click to expand...


You don't really have any way of knowing exactly what's in there, EP90 has a very distinct smell, but even if it smells of that it could still be a mix, so changing it for new would at the very least mean you would know exactly what was in there.

The drain plugs have a sump in them where a lot of the debris ends up, so you could have a look at what's in there while it was draining. Unless you leave it overnight after draining when hot, you're unlikely to get all of what's in the release housing out, and the same applies to refilling from empty, the release housing will take longer to fill, so checking the level again after some use, may show the level as having dropped a touch.
 
SydneyRoverP6B said:
I understand that classis minis also use engine oil in the gearbox.. :?
Click to expand...

The classic mini gearbox is effectively in the sump of the engine so uses the engine oil. i.e. there was not separate engine and gearbox oil.

Richard
 
As I have said before I have not done much with cars before but this to ke is fascinating I always thought oil was oil a gearbox is a gearbox and so on. Their is so much more to all this and it's good to know you guys are here to help me out even on my daft questions :oops:
 
the rover p4 uses 20/50 engine oil too,i remember reading somewhere about p4 production gearbox problems and that the first couple of hundred had the gearboxes changed in the car park!regards rich
 
I've been using Millers classic mini oil in my car's gearbox for a while. I change it every second engine oil change (6000 miles). I haven't noticed any real difference from the usual 20W-50 but the gearbox in my car whines a bit in all but top gear anyway.

Dave
 
Mine whines in 2nd and 3rd only a bit Seem to remember my other older cars having same whine. A 3500 and a Morris Oxford does anyone have a p6b with a quiet 4 speed box or do you have to go for the 5 speed
 
They do tend to be a bit noisy, even from new, but not obtrusively so, not helped by the all aluminium casings. Make sure that the speedo, filler plug and gearlever bungs are all correctly place in the tunnel, as well as the reverse light plate, to stop any noise getting into the cabin.
Other than that make sure it's full of oil, and keep your foot off the loud pedal.
 
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