Best oil for 265 Getrag box to stop leaks

[Mark]

Hi,

I have a Getrag 265 five speed in my e12, it has Redline synthetic oil in the box, any ideas what type of oil I should put in to help stop the minor seal leaks it has, im guessing I may need to go for a thicker mineral oil, I realise this may make the shift less slick, but it may be a better bet now until I save up for a rebuild,

Thanks,

Mark.

[John in Simi Valley]

Mark,
I don't know of any gear oil sealer, so I can't help there.

---BUT--- if you describe the oil leak more specifically, maybe we can help with a repair. Is it the front seal, rear?

[Mark]

I think it is leaking from the front and the back, I put a foil tray under the car last week, its not bad, but id like to do something to reduce the loss, but im not in a position to be able to take it off and fix it at the moment,

[alotawatts]

Some say don't ....but most say it's okay to mix synthetic and dino oils.
I you are lucky it's just the speedo drive seal !

[Mark]

Ive also been reading about hypoid or non hypoid oils, and GL4 vs GL5

The consensus seems to be, use non hypoid because it doesnt eat yellow metal in the box, but interestingly because of this some people recommend using GL4 oil, but this seems to still be hypoid, apparently non hypoid is GL3 and lower, and GL5 is not good because its hypoid, so im kind of confused now. I think I need a non hypoid 80 weight gear iol to mix with my Redline MTL. Any suggestions on brands,

[Peter Florance]

I'd heard bad things about GL5 but I bet GL4 is not easy to find. Maybe fleet supply business might have it

[Mark]

According to Redlines web site, their MT-90 is thicker than the Redline MTL that is in the box at the moment, and its a GL-4, could be what im looking for, im hoping the fact that its a little thicker means reduced leaking, not that scientific, but hopefully it will have the desired effect.

[BradInTexas]

I changed gearbox oil and put in Mobile 1 because it is all I could get in my area that would work, all the dino oils were GL-5. Now I wish I had left it alone because a good portion of the Mobile 1 is in my driveway. I believe in a post long ago someone mentioned using 30W motor oil and it worked fine. I may try that next. I also have a quart of Lucas Oil Stabilizer, which is nice and thick. As you can tell, I am basically out of ideas.