Thread: Question re Transfer Case Oil (with Roverdrive)

Hi Folks,
After some work had been done on my gearbox and transfer case replacing seals my transfer case was filled with Penrite Mild EP gear oil.
After about a thousand kilometers, including some towing of a relatively heavily loaded camper van up some steep hills (eg Cape Jervis SA which needed first gear with overdrive engaged, so there was only first gear left) I noticed when checking the level that the colour had darkened. Since this oil is not a synthetic gear oil (recommended by the makers of Roverdrive) I decided to replace it with Nulon 75W-85 synthetic. (Both oils are GL-4 rated). When drained, the Penrite came out as a dark brown opaque colour, when the MSDS describes it as an amber coloured fluid.
Anyone got any suggestions as to the cause of the colour change? Has the oil been overheated? I filtered it through a rag to see if there was any metal showing but in 3 litres of oil there were no more than a few small flakes typical of normal wear on any gearbox.

Coop

Originally Posted by rick130

Quite a few reports on here of the Roverdrive fitted to LT230's running very, very hot.
Having said that, discolouration can occur with any oil and it doesn't mean it's breaking down but it can definitely indicate it's getting hot, although often it's only the dye discolouring (yes, most all oils are dyed that honey colour)

Having said that, I'd use a really good 75W-90 syn oil like Redline MT90 or Motul Gear 300 or Castrol Syntrans M 75W-90 (blended for large truck gearboxes)

Don't sweat the Gear 300 meeting the GL-5 spec as it's yellow metal safe. (dual rated GL-4/5)
MT90 is a GL-4 spec only oil, as is the Syntrans M and Redline state MT90 shouldn't be used in hypoid diffs.

Thanks Rick,
Glad to hear that it may only be the dye that discoloured and that the oil was probably OK. Heat must be an issue or they wouldn't have gone to the trouble of specifying synthetic oil and supplying the finned plate. Since my original post I've discovered that the forward end of the tie rod was connected to the inside of the shift lever instead of the outside during reassembly. This placed the tie rod extremely close to the transfer case and probably explains the rattling noise I was getting on over-run with the Roverdrive disengaged (this brings the rod very close to the case and a little torque reaction was probably enough to bring it into contact). That really had me worried. I'll relocate the lever today and see if that eliminates the noise.
Thanks for the suggestions, I'll use one of those oils at the next transfer case oil change.
Regards

Coop