synthetic gear oil in the diff?

[a.d._510_n_ok]

anyone running synthetic gear oil in their differential?

 

anyone using a brand they care to brag on?

[yello620]

Not in the Differential, but i do have Synthetic in my L20b.:D I think that i used Valvoline this last time.

 

Seems to me that even the Cheap synthetic would be way better than conventional oil.

[hessianben]

Running Redline Syn (GL5?) in my diff and Redline Syn MT90 (GL4?) in my tranny...

shifto smootho.... I don't remember the weights off the top of my head...

[MAG58]

I run synthetic castrol 75w-90 in my diff. Probably has 50k on it of hard miles no problem. I wouldn't run synthetic in the trans though. You need a GL4 lubricant to play nice with the yellowed metals.

 

Make sure if you have an LSD you use the additive if you don't want to nuke the plates though.

[hang_510]

royal purple LSD

(cuz the subi dealer was a PITA to deal with :fu: )

[zed]

I put Castrol 80W140 fully synthetic in my Nissan Hardbody and toyota 4x4 diffs. The diffs run much cooler with the synthetic oil than mineral oil.

[a.d._510_n_ok]

Well, I drained my diff and refilled with this stuff:

 

 

It wasn't enough so I topped off with this:

 

 

Seems a little smoother but how the hell do ya really know :lol:?

[datzenmike]

I run synthetic castrol 75w-90 in my diff. Probably has 50k on it of hard miles no problem. I wouldn't run synthetic in the trans though. You need a GL4 lubricant to play nice with the yellowed metals.

 

Make sure if you have an LSD you use the additive if you don't want to nuke the plates though.

 

Yes Nissan recommends GL-5 in the rear diff because it contains more extreme pressure (EP rated) additives such as molybdenum disulphide (MoS2) in the oil. As it breaks down sulphur compounds are released which will attack and corrode copper, a component missing in the rear differential. Anyone who has changed rear end oil will remember the sulphur smell of it.

 

GL-4, recommended for lighter duty in transmissions with brass (copper containing) synchros, on the other hand, uses less of these additives typically 1/2 as much and must pass a the ASTM D-130 test. This test determines how reactive the sulphur is against a copper test strip.

 

Be sure to change/replace your GL-4 tranny oil regularly (30,000 mi) to remove the free sulphur compounds in it. GL-5 is NOT recommended where GL-4 is used no matter what some counter dick tell you. Newer trannys may not have brass but steel servo synchro rings??? BUT these are old trannys designed for GL-4, end of story. Yes you could use GL-5 in a pinch but replace asap.

Edited September 14, 2009 by datzenmike