Stock R33 Rear Diff Oil Recommendation?

[KrazyKong]

What brand and weight are people using on their Skylines for the rear diff oil?

I have a '96 R33 GTST Auto. It's pretty much stock accept for high flow, an air pod, boost grounding and a FMIC. I havn't upped the boost or done any other mods to the car.

I saw this thread here http://www.skylinesaustralia.com/forums/topic/317121-how-too-change-front-and-rear-diff-oil/ where is mentions

R33 Standard rear diff - 75w-90

Am wondering if that is what people are actually using, or if they are using something else. I have no idea when the diff oil was last changed, so figured it was time I put some new stuff in.

I'm using G&W Syntrans in my auto transmission btw, which is pretty much identical to the Castrol Transmax Z.

Anyway, wondering what my options are as far as Brands for the diff oil, and the correct weight to use.

Edited October 29, 2011 by KrazyKong

[Moodles2]

75w90, 80w90, 85w90, 75w85 all 4 will do as they are pretty much sameness. As long as the gear oil conforms to at least GL-4 (GL-5 is fine too).

If i recall correctly GTST's have a viscous LSD which means the LSD component is sealed and don't need an LSD specific oil, whereas GTRs have hypoid LSDs which require a LSD compatible oil.

[central coast person]

Standard or LSD???

If its just the standard rear diff +1 for post above. The GL rating is like a quailty rating and its just 4 or higher.

If its a LSD is more important you must use 80w-140, the reason is because its a hypoid type oil and a hypoid diff has such high pressure between the crown and pinon gears that if it was normal oil in there it would squeeze the molecules out between the pinion and crown gears and not lubricate it.

[KrazyKong]

I'm pretty sure my car is a standard and not an LSD. I don't have the LSD light on my dash. Is there another way to verify what's in my car?

I went ahead and put in some Castrol Rear Axle LSX90 (GL-5) based on a friend having it in their '95 R33 GTST Series 1 Manual.

However something strange is now happening which could be a co-incidence or not. I have an Auto as I mentioned before. The gear changes are smooth, but actually moving the gear selector from "P" to "D", or even "R" is hard to do. I can feel something thumping into place and is directly related to me moving the gear lever in and out of "Park". It's very similar to when you park facing down a hill and the car rolls a fraction when you put in and out of "Park". This happens in the morning mostly, and isn't as noticeable when driving home from work. However the weather lately has been warm so I'm not sure this is a temperature related issue. Previously the weather made no difference even in cold Winters to being able to move the gear selector smoothly.

Is the gear lever/selector directly connected with the Axle oil, or only with the transmission fluid? I had brand new fully synthetic trans fluid put in the car for a service a year ago.

What should I do? Will driving the car damage anything right now? Is my gearbox about die? or did I put the wrong axle oil in. My gut feeling is I might have the wrong axle oil in my car, but right now I'm not sure what to do.

Edited November 4, 2011 by KrazyKong

[ARTZ]

has nothing to do with your diff oil ...

[GTSBoy]

Changing the diff oil might (as in just might) make the backlash in the diff slightly more noticable so that when you change into/out of gear with the auto selector, the change in direction of load via the tailshaft to the pinion/crownwheel will result in a little thump as the gears mesh up. Maybe the oil that came out was quite a thick one, or maybe it was a proper LSD oil and so had some different properties that masked the thump.

I wouldn't worry about it.