Synthetic GL5 gear oil - it is bad for brass?

gortnipper · Jan 14, 2021

Onder said:
The wear looks like mechanical wear not so much yellow metal being eaten by evil compounds.

From the original post:
Photo below shows the black stained worn syncro on the right.

Synthetic GL5 gear oil - it is bad for brass?

"In normal operation, the sulfur/phosphorous additive forms a black sacrificial coating on the gears and anything it touches with a little pressure and temperature. As the gears turn, instead of wearing, the sacrificial coating of additives is peeled off or worn off. This is normal and acceptable in all steel gears. But when one or more of the surfaces is brass or another soft metal, the sacrificial coating is stronger than the base metal, and instead of just peeling off, it takes with it a few microns of the softer metal."

Onder · Jan 14, 2021

Well yes I saw that. But is the wear caused by chemical attack or simple mechanical wear? Staining really doesn't mean much.
I do get the point that the yellow metal is peeled off because it adheres to the black coating. If you use GL-4 in a older gearbox
what does the wear look like? Is it a case of no black deposits but similar wear?
I doubt most of us put on that many miles on our Norton's so can we say all the wear is caused by chemistry?
No, I don't know I'm only asking.

Fast Eddie · Jan 14, 2021

Also, as the gearbox in question is from a 1949 Jeep, how old is the brass synchro in questions do we think ??

Onder · Jan 14, 2021

...May the jury note that the defendant ADMITS to beating the living snot out of his vehicle!
Defense, your witness..

jseng1 · Jan 14, 2021

Onder, Fast Eddie and everyone.
The Willys was designed for 90 HP 6 cyl. Now it has a V8 Ford 260 small block. Everything has been rebuilt more than once. Its a work truck and gets abused. I've blown the tranny, ft & rear axels. It also has a PTO winch for pulling logs and a Studabaker overdrive. I just wore out the pistons a month ago and blew the motor with a broken piston. But I love the damn thing and its done amazing things. Its been in constant service since it was built, once was a Phillips 66 service truck in Idaho. Below is a photo after freshen up paint job. In background you can see the trailer I use to haul a cord of wood. I used to cut wood for a living.

seattle##gs · Jan 14, 2021

I put GL5 in my Goldstar gearbox way back when. The high gear bushing was sintered bronze, something like bronze powder mashed into a bushing shape. Did not know anything about this until I saw a steady stream of bronze dust coming from the mainshaft area. By chance I found the answer on this forum and have never used GL5 again though I think it only affects sintered bronze.

seattle##gs · Jan 14, 2021

jseng1 said:
Onder, Fast Eddie and everyone.
The Willys was designed for 90 HP 6 cyl. Now it has a V8 Ford 260 small block. Everything has been rebuilt more than once. Its a work truck and gets abused. I've blown the tranny, ft & rear axels. It also has a PTO winch for pulling logs and a Studabaker overdrive. I just wore out the pistons a month ago and blew the motor with a broken piston. But I love the damn thing and its done amazing things. Its been in constant service since it was built, once was a Phillips 66 service truck in Idaho. Below is a photo after freshen up paint job. In background you can see the trailer I use to haul a cord of wood. I used to cut wood for a living.

My stepfather loved these trucks, had 3 or 4 of them. How do you like those vacuum operated windshield wipers? Of course, in southern CA. it's not so much a problem. Try driving one in a snowstorm.

jseng1 · Jan 14, 2021

seattle##gs
What puzzles me is that one brass syncro was destroyed and the other perfect (so perfect that I left it in). The 3rd gear syncro was the worst when it should have been the 2nd gear syncro since it gets more use. The vacuum wipers had to go a few years ago. Most parts that could rattle off or break down have long since been "redesigned" along with the hood and the bed, the door latches etc etc. The yellow cap near the rear tire is the propare tank filler. It will probably still be running after I'm gone (along with my featherbed). This is what I used to transport my race bike to Willow springs in the 80s. Shake rattle and roll.

Onder · Jan 15, 2021

I wasn't trying to pull your chain but rather was aware it was a truck that earned its keep. It is abused actually as you say the 90 horse four banger has been long gone.
At this point I guess we can all go to synthetic passed for both GL-4 and 5. You can use up your remaining supply of GL-5
for bar oil!

Fast Eddie · Jan 15, 2021

jseng1 said:
Onder, Fast Eddie and everyone.
The Willys was designed for 90 HP 6 cyl. Now it has a V8 Ford 260 small block. Everything has been rebuilt more than once. Its a work truck and gets abused. I've blown the tranny, ft & rear axels. It also has a PTO winch for pulling logs and a Studabaker overdrive. I just wore out the pistons a month ago and blew the motor with a broken piston. But I love the damn thing and its done amazing things. Its been in constant service since it was built, once was a Phillips 66 service truck in Idaho. Below is a photo after freshen up paint job. In background you can see the trailer I use to haul a cord of wood. I used to cut wood for a living.

Looks kinda cool Jim I gotta say!

But is it only me that can hear ‘Banjo Duel’ in the background...?!?

jseng1 · Jan 16, 2021

Fast Eddie said:
Looks kinda cool Jim I gotta say!

But is it only me that can hear ‘Banjo Duel’ in the background...?!?

I think the appropriate phrase is "Boing diggy boing diggy diggy boing boing."

My snooty musician friend calls it the "Jed Clampett mobile".

Synthetic GL5 gear oil - it is bad for brass?

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