will they be ok?

2002 Discovery II
115k miles

 

they'lll be fine!

 

They came with synthetic, why switch cause of the cost? Do you know what new spider gears will cost when they fail?
If you were changing your gear oil once a year cause of heavy wheeling you might get away with it but I wouldn't suggest it for a 30,000 mile service.

 

They'll be fine.

 

Might be fine for a D1 but Rover at least got a little smarter with the D2 and the number of dif. failures and changed to synthetic fluid, didn't totally fix the problem but we still have weak dif's and anything that can help, in this case a synthetic oil, is a step to a little longer life especially when off road.

 

I'd never heard of a synthetic requirement / recommendation in the diff of any vehicle I've ever owned so I had just picked up some 80w90 and checked the owners manual for capacities. That's when I discovered the synth rec.

Not a difficult job to do by any means and the synth was only a buck or two more but if it'd be fine for a year or two I'd let it ride as long as no long-term damage.

Thanks
Brian

 

Conventional is fine is the diffs, just keep the change intervals reasonable. The transfer case gets hot from the cats and exhaust so either synth or a thicker heavy duty conventional gear oil (ie Rotella 85w-140 with yearly changes) is def. recommended IMO.