Thread: R380, transfer case and Diff synthetic oils

Interestingly, when I had my rear diff rebuilt ( It's a MaxiDrive locker, if that makes any difference ) the diff mob refused to warranty it if synth oil was used. They supplied and recommended Hi Tec oil, an Australian brand I had never heard of, which was considerably cheaper than the big brand oil I was going to use.

Originally Posted by rick130

Yep, TD5's use g/box cooler which is simply a piece of tube that travels up to near the front and heads back to the box, complete with a t/stat in the housing on the 'box, but no finned heat exchanger as such..

V8's used a g/box cooler too, but the poor old Tdi's missed out. Apparently not enough power to worry the R380.

My 300 has a cooler that looks factory. Is that a retrofit then?

The D2a missed out on engine oil coolers intetestingly. Cheers

Originally Posted by jbe

Fair enough. However, there was a noticeable difference in the ease of shifting straight away. Anyway, I'll be doing 400k's tomorrow plus a day of four wheel driving and another 350k's on-road on Sunday. I'm curious to see if stays like today.

Gear 300 is good stuff.
Put it this way, the change won't deteriorate.

Originally Posted by johntins

My 300 has a cooler that looks factory. Is that a retrofit then?

Maybe ?

Does it have a cooler like the V8 one up in front of the radiator ?

FWIW the UK army Wolfs which use the Tdi have a massive g/box cooler in front of the radiator.

Originally Posted by johntins

Interestingly, when I had my rear diff rebuilt ( It's a MaxiDrive locker, if that makes any difference ) the diff mob refused to warranty it if synth oil was used. They supplied and recommended Hi Tec oil, an Australian brand I had never heard of, which was considerably cheaper than the big brand oil I was going to use.

Not all synthetic oils are created equally, often a blender will scrimp a bit on the additive package when they use 'better' base oils, and you end up with a lesser lubricant. or just use the syn label for marketing, "it's 'synthetic' so must be better, right ?"

Some of the absolute best diff lubes you can buy anywhere are blended by Lubrication Engineers in the US and half their lubes are straight mineral oils which outperform most all big brand name and most boutique syn diff oils.
Caltex also offer Borate Ester based diff lubes which are bloody brilliant too. I don't have any experience with Penrites Borate Ester 85W-110 fluid, but it should be good. Both use mineral oil bases.

As with any oil it's the sum of base oils+additive package.

Twenty five years ago premium syn lubes flogged mineral lubes, these days the lines have blurred as most 'mineral' oils are blends anyway, and a lot of 'syn' base oil is heavily refined Group III oils.
The best Group III oils are up there with Group IV PAO's in terms of performance so the oil guru's have told me.

Having said that, I've heard of a number of diff crowds say "syn is crap, it'll void warranty if you use it" but I've never seen a straight answer as to why ?
As I said above, it's the extreme pressure additives that stop things going pear shaped in diff oil, not the base oils.
Syn base oils cope better with higher running temps, and resist oxidation and oxidative thickening better than straight Group I and Group II mineral oils.

Originally Posted by ozscott

Jbe was the Penrite the fully synthetic pro oil?

Cheers

Checked my old invoices and they say Penrite Pro Gear Synthetic 70/75. Done about 470 km so far and the Motul Gear 300 it still feels better, i.e. smoother down shifts and the mild crunches into 3rd gear have disappeared when I use the clutch a bit too sloppy.

Nice thanks mate. Cheers