OIL weights, and.....

mrvette

Phantom of the Opera
Joined
Mar 24, 2008
Messages
15,207
Location
NE Florida
LONG time ago, I got to reading about modern stick shifts using ATF and much thinner oils in the trannies.....

the olde muncie in this '72 shifted like a tree trunk....so I up and changed over to 30 weight syn engine oil...Mobil 1.....and it shifted SO much smoother, and lasted some 3 years before I tossed it over for a automatic overdrive....

so it makes me wonder if some GM additive and 30 W syn engine oil is not good for diffy's....

I know that diffy's in FWD cars seem to run on ATF...so why not???

:bonkers::flash:
 
LONG time ago, I got to reading about modern stick shifts using ATF and much thinner oils in the trannies.....

the olde muncie in this '72 shifted like a tree trunk....so I up and changed over to 30 weight syn engine oil...Mobil 1.....and it shifted SO much smoother, and lasted some 3 years before I tossed it over for a automatic overdrive....

so it makes me wonder if some GM additive and 30 W syn engine oil is not good for diffy's....

I know that diffy's in FWD cars seem to run on ATF...so why not???

:bonkers::flash:

So your muncie only lasted 3 years after your put in the 30w syn?
 
LONG time ago, I got to reading about modern stick shifts using ATF and much thinner oils in the trannies.....

the olde muncie in this '72 shifted like a tree trunk....so I up and changed over to 30 weight syn engine oil...Mobil 1.....and it shifted SO much smoother, and lasted some 3 years before I tossed it over for a automatic overdrive....it was examined and pronounced in good shape by the purchaser, as I knew it was...

so it makes me wonder if some GM additive and 30 W syn engine oil is not good for diffy's....

I know that diffy's in FWD cars seem to run on ATF...so why not???

:bonkers::flash:

So your muncie only lasted 3 years after your put in the 30w syn?

UN, NO tranne was pronounced good, and sold....the guy who bought it took the side cover off, and agreed....

to amend my post....

:hissyfit::lol:
 
LONG time ago, I got to reading about modern stick shifts using ATF and much thinner oils in the trannies.....

the olde muncie in this '72 shifted like a tree trunk....so I up and changed over to 30 weight syn engine oil...Mobil 1.....and it shifted SO much smoother, and lasted some 3 years before I tossed it over for a automatic overdrive....it was examined and pronounced in good shape by the purchaser, as I knew it was...

so it makes me wonder if some GM additive and 30 W syn engine oil is not good for diffy's....

I know that diffy's in FWD cars seem to run on ATF...so why not???

:bonkers::flash:

So your muncie only lasted 3 years after your put in the 30w syn?

UN, NO tranne was pronounced good, and sold....the guy who bought it took the side cover off, and agreed....

to amend my post....

:hissyfit::lol:

Ok. sounded like it died 3 years after.
 
When we restored my friends 68 XKE some years ago, the factory manual said "30 Wt Motor Oil" for tranny lube. When we checked with the local Jag nuts, they said "No fuggin way." The factory recinded this years ago as bad advice.
Rear ends rely on that "clinging" function of 90 wt for lubrication. No WAY would I ever even consider it.
 
From what I can assertain, ENGINEERS like as thin of an oil as possible to do the job intended.

Many high end race guys try to run 0-20. Nascar is even going to multiweight.

Personally, in a motor, I'm not partial to anything less than 5-30

As to my differential. The store had 85-140. I know that for the most part, gear oil I'm used to seeing is 90 weight.

IDK, in a diff it's different than in a motor I'd say. Less heat and stuff.
 
From what I can assertain, ENGINEERS like as thin of an oil as possible to do the job intended.

Many high end race guys try to run 0-20. Nascar is even going to multiweight.

Personally, in a motor, I'm not partial to anything less than 5-30

As to my differential. The store had 85-140. I know that for the most part, gear oil I'm used to seeing is 90 weight.

IDK, in a diff it's different than in a motor I'd say. Less heat and stuff.

You bet. The engine oil is pressurized, not relying solely on film thickness for protection. The diffy has no pressure, totally relying on film strength.
 
From what I can assertain, ENGINEERS like as thin of an oil as possible to do the job intended.

Many high end race guys try to run 0-20. Nascar is even going to multiweight.

Personally, in a motor, I'm not partial to anything less than 5-30

As to my differential. The store had 85-140. I know that for the most part, gear oil I'm used to seeing is 90 weight.

IDK, in a diff it's different than in a motor I'd say. Less heat and stuff.

You bet. The engine oil is pressurized, not relying solely on film thickness for protection. The diffy has no pressure, totally relying on film strength.

I WAS told by some source that sounded believable that diffy's got hot as much from churning around oil, a energy waste, and even though I have not tried syn engine oil in a diffy yet, it seem very plausible to me so at some point I have to get off my ass and find some GM additive, and some syn 30 wt and give it a go, I know the muncie shifted like a import after that oil change, slick as any new tranny....GONE was all that notchiness in the shifter feel....I dunno if it ran any cooler though, I suspect not, given the headers/pipes, engine heat, etc...

:rain:
 
I have been pondering draining the oil in my muncie and giving it some royal purple.

They also make a gear oil for the rear end.

I have also heard that the brass in the muncie hates synthetics.
 
I have been pondering draining the oil in my muncie and giving it some royal purple.

They also make a gear oil for the rear end.

I have also heard that the brass in the muncie hates synthetics.

All I can say is MY Muncie shifted slick as snot on a brass doorknob....

:devil:
 
Top