lube confusion

[fixkick]

Quick question.....

http://www.fixkick.com/tranny/napa.JPG for 5spd tranny AND diff


http://www.napaonline.com/p/COR613 for transfer case in the rear

i have been over and over your pages, and am a little confused. Different terminology.
The rear axle is the transfer case? never the transfer case is bolted to the rear if the main transmission. and runs GL4.
The differential is what the two front axles bolt to?

GL4 for tranny, do not use GL5? (that means GL5 only lube but some lubes are GL4/and GL5 all in one like the napa jpg above. shows.)

GL5 for axle yes, (transfer case No)
both the front and rear differenetial gear cases run GL5 only , GL5 is Hypoid gear lub, see that funny offset drive pinion, its under huge stress and needs GL5, never gl4.

That page blows my mind*:0

there is no confusion,
the book is clear as day, axles GL5 , boxes GL4. boxes 5sp its sidekick mr. transfer case.
what is the confounding is this.

1: some oil companies make a DUAL lube, like your first link above shows.
2; most stores sell no, GL4 of any kinds, that is because, A: LESS THAN 5% OF CARS HAVE STICK SHIFTS, AND B: MOST of those owner never buy lube, so stores are loath to stock it.
3: Some GL5 lube is loaded with sulpur, and eats up brass syncros, that is why penzoil sells syncro mesh lube, just for these boxes.
4: some SYN lubes cause the sycnrhos to slip bad and grind gears or bulk.

MT1 is for 1950 , manual transmissions with crash boxes, has no syncros in the box. at all. so MT1 , means ZERO today.

if it does not say GL4 on the bottle do not use it in the boxes.
a one line , simple, rule.

if you call the oil companies, hot line 800
they all say the same.

the problem is API, THEY DRAGGING FEET ON THE NEW GL6 (OR WHAT EVER THEY WILL CALL IT) SPEC. OUT A GL5B OR GL6 THAT IS OK FOR GEAR BOXES
THAT IS THE PROBLEM. TOO.

---

GL5 DOES not damage the box gears. ever. (if you dont grind the dogs, but the gear teeth or ok)
its ok ,just the synchro ring issues.
both damaged (sulphur) and or they slip and grind dogs or balk

putting GL4 (pure only) in to any hypoid gear axle, is really bad. (its is not Extreme pressure rated)

but some gear lube makers can do both at same time. (there is no API spec for this, its and advanced idea) and good.