Modern Gearbox Oil for WC51 T214

[Pedr]

G'day Gentlemen.

A quick bit of help if I could,

Does anybody know what the correct gearbox oil is or a modern equivalent for a '43 Dodge with the standard engine and box in.

I forgot to look in the manual ( They're at a mates place ) and I want to put some oil in the box.

Its a hot climate here.

Thanks in advance.

Pedr

[Lynn Eades]

EP80 or EP90,which is good for G/box, and T/fer case. There is a bronze thrust pad against the crown wheel, so a 90w oil would suit the diffs.(EP oil eats bronze)(you can use the 90w in the gbox)

[Phil Waterman]

Originally Posted by Lynn Eades

EP80 or EP90,which is good for G/box, and T/fer case. There is a bronze thrust pad against the crown wheel, so a 90w oil would suit the diffs.(EP oil eats bronze)(you can use the 90w in the gbox)

The comment "EP oil eats bronze" could you explain a little more? First what does the term EP stand for? Is this a brand issue only in New Zealand and Australia? My reason for asking is of course there are lots of bronze bushings etc. in CMPs and this is first I had heard of one of the gear oils being non-compatible.

Cheers Phil

[Lynn Eades]

You are right. It is brand specific. Most oil companies produce a std mineral oil range, and a heavy duty range. Often the heavy duty range carries additives that attack bronze, and aluminium. These oils are for where there is a high tooth face pressure, as well as a high sliding situation, as in a hypoid diff.
Pedr, what did you end up using?. I was wrong about the EP oil,in the Dodge box. It should have a straight mineral oil, as there is a bush inside the reverse idler,that might be damaged.

[Dinty]

G'day All, My undestanding of the term "EP" extreme pressure only what I remember being told a long time ago, cheers Dennis

[Jeroen Sleijpen]

There is a difference between Hypoid and non-Hypoid gears :

"Hypoid" is not really a question of oil, so much as a question of
gearcutting. Old (1920's) rear axles used straight bevel gears to form
the crownwheel and pinion. These had two disadvantage, the pinion
shaft meets the crownwheel on its central axis, and the straight cut
gears are noisy. By using a more complex "hypoid" gear tooth shape (if
you look at a pinion, the teeth appear twisted) these problems can be
addressed. The more gradual engagement of the teeth along their length
reduces noise. By careful design of the geometry the pinion can be
made to mesh _below_ the axis of the crownwheel. As the centre height
of the crownwheel is fixed by the wheel height, this allows the
propshaft to be lowered relative to the car body, giving a clearer
floorpan and lower centre of gravity for better cornering. Hypoid
bevels are now universal in this application.

Because of the sliding contact that hypoid gears make, their
hydrodynamic contact pressure is higher. To be suitable for use with
hypoid gears, a lubricant must be capable of resisting high pressures.

Oils with "EP" ratings (Extreme Pressure) such as EP90 are required.
Some brands describe themselves as "hypoid" instead, a term which is
synonymous with EP. GL-5 is a formal API standard for this type of oil
(comparable to MIL-L-2105B/C/D)

A manual transmission won't usually contain hypoid gears, so it
doesn't need an EP oil. Rare exceptions are those transaxles where the
crownwheel and gearbox share the same lubricant. Fact is that a EP oil often contains sulpher additives which will "eat" brass parts. The sulphur additives are required for Extreme Pressure on the oil at point contact in the teeth of the hypoid gears in the ring and pinion gear set.

I use 80w90 mineral oil in all my MV's without any problems.