Since I have Nix all jacked up greasing rear wheel bearings in preparation for a road trip Saturday, it seemed like a good idea to change out the gear grease in the diff. It's probably not been done since 1986; high time I thought.

We have 2 different gear lubes here, specification GL-4 and GL-5.

GL-5 contains molybdenum which eats up brass thrust bushings whereas GL-4 contains no moly, and is safe for brass.

Questions:
1) Are there any brass thrust washers in Dana diffs or are they steel shims?
2) Whether or not brass is present, which lube spec is best for my 40 year old gears?
(';')

 

Elinor.

No brass that I can recall, but I would use the GL4 of 85W140 spec, or something very close that your market provides.

 

I have just always used.90 weight gear lube, but now apparently i have to something else due to having a limited slip dif, guess i will cross that bridge when i get to it.

 

Thank you, Grant! As it happens, the GL-4 is the one with the handy pump!

We always used 90 on the farm (one of the warm, comfortable smells of my childhood, probably because it was in the shop and not in the house), it came in 5 gallon buckets with a lever pump on the lid. GL numbers confused me.
(';')

 

Yeah, 90W has always worked for me.
No LSD diffs here. But, if one came in an additive is the
answer.


140W for extreme hot weather or very worn diff's, only a weak
mebbe.


Carl

 

I'm impressed you knew there was a potential issue to ask the question. I go to the store and go ummph diff oil, that one will do. Male shopping.

 

AND, we get it easier down here with gear oils.

The brands I have used for years, Nulon, Penrite, are ALL LSD compatible, so us males can think of more important things.

A non LSD diff can use LSD oil without issues, but the other way is not the best, unless the additive package is used.

90 is just fine, just I have used the 85W140 since the MK7 days, and no issues, but then we do get it HOT here, and that inboard diff runs HOT in my opinion.

I noted yesterday that my 2 S Types run a 80W140 Full Synthetic in the diffs.

 

We had different kinds of gear lube when I was growing up. Straight 90 came in the aforementioned 5 gallon bucket with the pump (pumps were expensive, purchased separately so we took care of them!). It was used for the big trucks and other things without Positraction (Chevy's trade name as I understood). Lube was changed once a year just before Spring work began.

But I was sternly counseled NOT to put that oil in the car, or any of the pickups with Positraction as it would Ruin them and render them only as useful as a "normal" diff. There was a special oil to put in Positraction rear ends and that's ALL I was to put in them. It was even kept in a different building from the "ordinary" 90.

I learned about the moly/brass problem in college. (I learned all sorts of useful stuff there!) We didn't do diff repairs though, they were relatively cheap and plentiful in wrecking yards so it was giving trouble (whining was the biggest complaint, broken tooth on the ring gear [from high RPMs, spinning tires on ice and sudden contact with dry pavement, usually repeatedly], came in second), just change out the center section.

Nix is all ready for the driving season now, lubed from stem to stern as they say. The old oil was very dark, but as I remember 90, it was very dark green right out of the bucket, with a distinctive, pungent, friendly smell!

So we're off tomorrow on the first road trip of 2016, and it promises to be a Gorgeous day on a twisty mountain road! (Nix Loves twisty mountain roads!)

One of Nix's younger siblings is being trailered from her home near Clear Lake, Ca. to the Club rejuvenation facility in Loomis, near Sacramento. As Nix has experience being loaded and riding on trailers/flat beds, she asked if we could go along to lend her sister moral support and encouragement. I said, Sure.

I have also been asked to also photo-document the loading process (and the accompanying party) for the Club newsletter. So I have an official excuse!

It's a Tough job, but we'll do our best.
(';')