Hoses and other implements to court gravity certainly work, but can be messy, and are not always needed.

In most cases, the plastic bottles gear oil comes in can be squeezed to expel a good 2/3 (or more) of the oil at an upward angle without the benefit of gravity. Bottle can then be refilled, and another 2/3 of a quart can be 'injected' in. If the bottle has a nice pointy spout, this usually works with little or no mess, and it is easy to cuttoff the supply right at the point of overflow.

Anyways, most diffs have plenty of clearance for this simple method. Many manual trannies do not...

Best of luck.

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1986 300E 5-Speed 240k mi.