Differential Oil Question

[JeepGeek]

Hi all,

Probably been asked a hundred times before but did a quick search and couldn't find anything.

I'm looking to replace the oil in my diffs on the 353. The manual refers to SAE90 gear oil.

Now am I okay to use a EP90 GL-4 gear oil? I ask because I made an inquiry on a UK supplier who said that the EP90 oil they were selling was not suitable for vintage vehicles as it had additives, but they did stock SAE90 oil.

I thought EP (extreme pressure) was used for Hypoid gears but could be used for non-hypoid gears (don't know if the CCKW has hypoid gears but the jeep diffs use hypoid oil).

Also I understood that GL-5 oils contained additives that could attach bronze? (hence the use of GL-4)

I think the confusing thing is the interchangability of EP, SAE and GL in the oil descriptions.

Thanks

Jon

[dr deuce]

The newer oils you will find cause leaks.

I have not had a problem in 60k+ miles with the newer oil except leaks...

They are hypoid. If the pinion shaft is below the centerline of the axleshafts, it is a hypoid diff

[US6x6]

If you can find it in your part of the world, the Penrite Mild EP is an excellent gear oil for box, t/c, doffs joints etc.
http://www.penriteoil.com.au/products/g ... p_gear_oil

[Fernando Mendes]

"don't know if the CCKW has hypoid gears"(Jeep Geek)
Yes,both CCKW and Jeep have hipoyd tooth gears in differential.

[dr deuce]

CCKW with splits is spiral bevel. Note the pinion is even with the centerline of axle

[Fernando Mendes]

Mine is a Banjo type doctor.I never looked the split(Ford) manual.