Why am I changing the gearbox oil so early?
It’s extremely hard to find correct EP90 gear oil in Switzerland, this is my experience at least. It’s also quite hard to ship into the country as most couriers don’t want to carry oils per sae. I was however supplied 1 litre of it by Land Rover at a truly eye watering price some months ago.
As an alternative to EP90 that’s, kind of OK, I have to used SAE 90 oil. It’s the same viscosity as EP90 but offers less protection in the long run. Extreme Pressure (EP) is well suited in gearboxes given the huge amount of force driven across the surface of the teeth.
Oil (in most circumstance) is there to provide physical separation between metal and metal. SAE 90 offers less protection in so much as it lacks the EP properties, doesn’t bond to the gear surfaces and doesn’t reduce wear as well… so that why I’m changing it.
Fortunately I found I was able to order sufficient quantity of Castrol EP90 for 2 full changes of ALL transmission fluids from Holden Vintage and Classic Cars . This is enough for 6000 miles of motoring.
Both gear boxes, the overdrive, front and rear axles, front axle swivels, steering box and steering relay are specified as oil requiring EP90. Currently only the steering box, steering relay and axles swivels have the correct oil. Time to rectify this…
I later measured what had come out (of both boxes) to check the right amount was in there. It isn’t unheard of for oil to migrate our of the main to the transfer box. Fortunately, both gearboxes had the required volumes.
GL 4 and 5 oils are corrosive to yellow metals due to their high content of sulphur and phosphorus. GL 4 is just about OK in a Land Rover gearbox but GL 5 will cause excessive and rapid wear to the bronze (yellow metals) within.
I was quite surprised at the colour of the oil after such a short distance. It could be that as all of the yellow metals are new and set up on the tight side of the workshop manuals tolerances, it’s just things finding their natural “size”.
With the oil drained out, I reinstalled the drain plug and dropped the oil in the transfer box.
It’s not actually necessary to measure how much oil you put in. If you remove the original filler plug on the side of the casing, the correct level it reached when oil starts to run out of the opening. On LGL, I have a dip-stick assembly and it’s a bit of faff to remove, hence the measuring jug.
Next comes the task / challenge / opportunity to refill the main gearbox. Oil is filled into the main box by the level plug on the side of the casing. It’s in a tricky location to say the least.
The ex-military Series 3 I had in the UK had a second rubber bung on the gearbox tunnel and a filler cap on the top of the gearbox. Why this wasn’t available to the civilian market I have no idea but I’m definitely keeping a lookout for parts to make these alterations.
Then I set about positioning myself under LGL and threaded the hose into the filler hole. Now I simply push the piston down right. Well, thats the physics of it.
In reality, the piston doesn’t seal well in the barrel. Any change in angle of the shaft sees oil bypassing the double seal running out of the back of the barrel, down the handle, up my arm and into my armpit.
Whilst I cleaned myself, workbench, floor and shoes, I mulled over what to do next.
Gravity it my friend in such cases… why didn’t I think of this in the first place…
I’ll do the axles at the next opportunity…