SM465 gear oil?????

[RingMaster4x4]

what gear oil is best for a SM465? I put 85w-140 gear oil in my SM465 and now I can't down shift it 1st. (not Low) Or is this something esle? I could down shift before I changed gear oil. (from the water that was in it. )

 

[rcurrier44]

I just use regular old 90W

 

[goldwing2000]

Usually 80W-90 in the tranny and 85W-140 in the t-case (NP205).

I'm sure you'll get somebody to argue about that, though.

 

[diesel4me]

80w90

I'd use 80W/90 gear oil,I tried 85W/140 in my 72 K5's SM465 and I almost broke the shifter off trying to get it into first on frigid cold mornings near or below zero!--and when I put it in neutral and let the clutch out,you could feel the truck try to go forward,like fluid drive!--In canada they use 80W gear oil or a lighter weight synthetic for easier shifting...another truck I had with an SM465 tranny that was noisy I put 2 cans of STP gear oil treatment in it--same thing but worse--too thick to shift it in cold weather--it did quiet it down a lot though..

 

[RingMaster4x4]

Sounds good thanks for the help. I will try it and see what I get.

 

[Mule man]

I put some 75W synthethic gear oil in my 465 and it made it much easier to shift--especially in cold weather (20 degrees in Arkansas)

 

[stock93]

IIRC, my chiltons says to use dexron 3 atf in my sm465 in my 83 model. Does anyone know why?

 

[K5MONSTERCHEV]

Is it rebuilt or what? Put 30WT init.

 

[dyeager535]

I wouldn't be surprised if it wasn't for economy. The 205 went with ATF later on as well...from what people say on here, you see more wear on the ATF fed 205 than you do with gear oil, so it can't be for better lubrication. MIGHTo have something to do with shift ease, but not sure about that, I have a feeling no matter whats in it, the 205 is just a pain to shift sometimes.

 

[jarheadk5]

Ringmaster - I haven't heard negative comments on Redline MTL. It's a synthetic 75W gear oil that apparently is the cure of choice for difficult-shifting trannies.

From the trans gurus at my former employer:
A gearbox (manual trans or T-case) has to be designed for ATF lubrication to get maximum lifespan. The tolerances between gears has to be a little tighter, and a pump is needed, since ATF doesn't "climb" like gear oil does.

 

[JonV]

SM 465: 1987-50
SAE 80W, 80W-90, GL-5
in Canada 80W GL-5

Capacity 4 quarts

Transfer case:
1981-89 All AF3 (Dexron-III)
1973-79 NP203 Full Time 10W-30, 10W-40 SE (engine oil)
1960-1980 all others, 80W, 80W-90, GL-5 (gear lube)


Capacity
1970-89 NP 205 5.0 pints

I live in the Mohave Desert. Gets hot here so I use straight 90W (ISO 220) GL-5 in the tranny and transfer case. I use ISO 320, GL-5 in the diffs.

If you have a limited slip, don't forget the additive.