30 wt. oil in manual trans?

[69roadr]

I had my 1969 Roadrunner trans serviced recently, tear down, inspection and reseal with new clutch and flywheel. After putting some miles on it, second gear started giving trouble getting into. I had to shift slow from 1st. to 2nd to finally go in. The guy that did the trans inspect told me to drain the 80 wt. oil and replace with 30 wt engine oil. It shifts fine now, but am worried if this is o.k. anybody ever try this, and if so, is it o.k.

 

[RustyRatRod]

I've never heard of engine oil, but a lot of them take ATF.

 

[Meep-Meep]

ATF is a factory callout but for really cold climate. What gear oil has that motor oil doesn't is the sulfur and other additives to give it more film strength for high pressure applications. Motor oil probably won't hurt it if you're easy on it but I think I would stick with gear oil. Have you tried a lighter viscosity gear oil? Or better yet find your local SWEPCO rep and get a case of the 201.

 

[Moparsmitty]

The factory called for 80W-90 hypoid gear oil. I would be reluctant to use anything else. 30W motor oil and ATF doesn't have the viscosity or shear strength for these old 4 speeds.

 

[benno440]

i spoke to passon performance and he and a few others recommend putting 1 qt of ATF in then filling the rest up with 80w-90 till the fill line, they reckon this is best

 

[69Bee]

I only used 80W-90 gear oil in mine, and would never suggest mixing fluids. Perhaps they didn't assemble the syncros properly. Another possibility is the shift lever arms are loose or the linkage rods were incorrectly adjusted.

 

[RustyRatRod]

The factory called for 80W-90 hypoid gear oil. I would be reluctant to use anything else. 30W motor oil and ATF doesn't have the viscosity or shear strength for these old 4 speeds.

....and what exactly are the specifications for viscosity and shear strength for all the different years of the A833?

 

[D575]

How about the synthetic gear oils like redline ? Has anyone heard anything pro or con ?

 

[RustyRatRod]

ATF has long been factory recommended for both cold weather operation and or if the gears made excessive noise to the owner. Not a thing in the world wrong with it. It's the FIRST recommended oil in many gear boxes today. I'm sittin here in front of MotorAllData and can pull up literally hundreds of applications dating all the way back to 82 that show ATF as a requirement.

 

[Hemi Rebel]

My bee had gear oil in it and when cold out you could not speed shift. Drive it for an hour and the trans was still to cold to shift fast. Drained the gear oil and filled it with syncroshift. Works like a charm.

 

[benno440]

what i stated is the best way of what alot of people have tried and tested and rusty is 100% correct

 

[Dako]

Another confirmation on ATF use. Had a `92 mazda in the stable that used ATF in the 5 spd. I doubt there was much difference in gearboxes (old to new)...other than it's orientation (sitting sideways).

 

[Meep-Meep]

One reason they use ATF in modern manual gear boxes is the synchro rings are not solid brass like the old stuff. The part that contacts the gear is a paper clutch material like an auto tranny and using gear oil will affect the shifting because of the different friction coefficient. Whether this design is fully responsible for the ATF switch I don't know, but it's part of it.

 

[69roadr]

so, in short, should i add 1 qt. of atf, and then fill with gear oil? never heard of putting atf in a manual tranny before lol.
bein this is my 1st. Mopar, and 1st. 4-speed car, i have lots to learn:icon_eek:

 

[Moparsmitty]

....and what exactly are the specifications for viscosity and shear strength for all the different years of the A833?

Don't know the exact factory specs for for viscosity and shear. All I'm saying is that several tech articles that I've seen recommend not using ATF in A833s. The one article I remember was in Mopar Muscle Magazine from November of 2011. I tried to post a link to this article but I guess the URL is too long to come up in a post. Also I remember seeing a FSB eons ago that said you could use ATF but only in extreme cold conditions.

 

[reindeer]

If I were you... I would definetly not mix the two fluids - I would run a full synthetic fluid - Amsoil - Good Luck whatever you do...

 

[RustyRatRod]

.....and I didn't mean that to be smartass. LOL I was actually lookin for you to school me on sumffin.

Don't know the exact factory specs for for viscosity and shear. All I'm saying is that several tech articles that I've seen recommend not using ATF in A833s. The one article I remember was in Mopar Muscle Magazine from November of 2011. I tried to post a link to this article but I guess the URL is too long to come up in a post. Also I remember seeing a FSB eons ago that said you could use ATF but only in extreme cold conditions.

 

[Moparsmitty]

.....and I didn't mean that to be smartass. LOL I was actually lookin for you to school me on sumffin.

You! A smartass? No way Rusty. You and a lot of other guys on this board school me all the time. And I can use it! LOL. :read2:

 

[benno440]

have a talk to jamie from passon performance or the guys at brewers.
passon has a special oil for there boxes, he told me the exact equivalent of it was a mix of atf and 85w-90.
he said 85w90 is too thick on its own and will sometimes cause shifting hardness, and atf was too thin to protect properly, so he said put 1 qt of atf in then fill the rest up with 85w-90, my box never shifted so smooth and when i freshened it up recently it was so clean i didnt need to touch it.

but ask the pro's if you dont believe me.

 

[moparmarks]

My 72 FSM calls for either gear lube or ATF in the 833