1974 R90/6 Transmission, any yellow metals?

[jgleadle]

I have a very low milage great condition 1974, the transmission is as new, i would like to keep it that way. I want to add Readline shockproof light in the transmission to reduce wear, but it is incompatible with yellow metals, ie brass syncros. did the 1974 have any yellow metal in it. FWIW, I have a 1989 Skyline GTR 800 awhp and this stuff really lessens the shock loading on the transmission, I am a believer after years of abuse and no failure. i would love it if the R90/6 could benefit from it. maybe even put it in the final drive.

http://www.redlineoil.com/Products.aspx?pcid=8

[Garnet]

The yellow metal that GL4 gear lube is specd for if normally found in syncros in automotive gearboxes. (VW the most common). Airhead boxes have bronze bushings and seem to be fine with GL5 spec lubes.

I have used Redline Shockproof for over 10 years now.

[barryh]

The story behind GL5 oils and damage to yellow metals is analogous to ZDDP where sacrificial anti wear material is deposited on metal bearing surfaces to worn away under boundary lubrication conditions. In the case of yellow metals some of the parent material is lost when the anti wear coating is worn off. I'm speculating here but it seems to me this mechanism would apply to high shear surfaces like gear teeth or syncros but might not apply to low shear surfaces like bearing bushes whatever they were made of.

This is the best explanation of the issue I've seen. He's writing about a specic Coravair application but it's still an interesting insight.

http://www.widman.biz/uploads/Transaxle_oil.pdf

[jgleadle]

why weight have you been using? where have u used it, trans and diff?

[jgleadle]

why weight have you been using? where have u used it, trans and diff?

[Garnet]

why weight have you been using? where have u used it, trans and diff?

I use the Heavy Shockproof gear oil in the gearbox, shaft and rear drive. I only use it in shaft if I have some left over as it is not that critical.