Hi,

I went to a mechanic yesterday and had the trans and diff/t-case fluids changed. He used ATF fluid from Land Rover, but when it came to the diff/t-case fluid, he used a Castrol fluid. It was in a 4 or 5 quart bottle, I didnt get the name but I saw it was a Castrol marked GL4 and SAE90 and also "manual transmission fluid" on it. I thought D2 uses GL5 but the mechanic swore his fluid was fine (and anyway the job was done). Is he right? Should I be worried and change it again?

I have a D2 year 2000 with 26,000 miles. I drive around 5000 miles a year only, no towing or offroading. Where I live the temp ranges from 60F in the winters and 95 in the long summer months.

Any advice would be helpful.

 

You are perfectly fine.
As for the transmission fluid, as long as it is Dexron III any brand is fine.

 

I use a combination of a GL6 fluid and Mobil 1 75W/140 gear oil for extra wear protection. If you use your truck a lot off road, you want all the wear protection you can get for your fairly weak spider gears.

 

Thanks guys, your replies mean I can sleep better tonight.

I kept reading everywhere that GL4 has half the EP additives of GL5 so I was worried all day :P

Mike, I don't go offroading, so would GL4 be enough protection for my gears?

 

For now, yes, with your next change, step up to a good synthetic and consider the heavier oil for more protection. Remember D2's came from the factory with a synthetic in the diffs and t/case.

 

Thanks Mike and Spike, really appreciate your advice as always.

 

I don't know about 1/2, but GL4 doesn't have the additives that cause brass/bronze parts to get eaten away, like GL5 does (or used to).
Though I recently read that they've changed to an additive in GL5 that isn't as bad. But I read it on a forum somewhere, so need to investigate further.

 

Yeah I read threads saying the same. I've also read that GL5 has twice the EP additives which provides extra protection, which is warranted in some gears. In general, from what I've read many cars spec GL4, perhaps because of GL5's corrosive characteristics. Though, like you, I've also read that many GL5s nowadays don't corrode anymore.

But like I said, this is all from what I've read online.

In my case, the D2 is specced for GL5, synthetic as stock.