OK, 10W30 and 70w80 gear lube is the same viscosity. i doubt the problems with the tranny are from anyone running 10W30 in them. More thank likely it had GL5 in it at some point.

10W30 is fine for the AX5/AX15, too many people run it (myself included, and if you bring it to the dealership for service that is what they will put in it) for 100K miles plus without issue.

There are plenty of transmission shops who will tell you to run GL5 in your manual transmission too, doesn't make them right. And motor oil promoting heat? What are you smoking?

Motor oil is yellow metal friendly, has plenty of addatives to protect bearings and gears. I fail to see why this is a problem or where any harm could be caused by the motor oil. In a cold climate you would want to run 70w80 in the trans, and that is the same viscosity as 10w30. In the summer you can run 10w40, but here in winter I would not.

 

75W90 will with stand much more heat as Captianof Iron posted. Plus motor oil and gear oil are engineer differently with different additives. They service to completely different purpose which is why one is motor oil and one is gear oil!

 

That is true, but you have some other serious problems in your trans if you are getting anywhere near enough heat where you are not fully protected by 10w30.

Gear oil does server a purpose and I would not run 10w30 in my differential, but gear lube in an AX5/AX15 can be too thick to shift well in colder weather. When I bought my new 1998 TJ and the shifter would hardly move when cold I brought it into the dealership. To fix the problem, guess what they did? They filled the trans with 10w30. I put 115K miles on that Jeep and never once had a trans problem, always refilled with 10w30 or 10w40 (in summer).

 

you are the ONLY person I've ever heard of who hasn't had trouble running 10w30.


you're obviously not a serious mechanic. anyone with intelligence who is a mechanic for a living will laugh if you tell them to put motor oil in a transmission.


frankly, I'd run motor oil in a differential before I would in a transmission. much less components to break in a diff than there are in a trans.



Coming from a guy who has rebuilt his fair share of AX series trannies....there's alot of moving parts in there. I want the RIGHT fluid in it.

 

Funny, this is the first thread I have ever seen of anyone having troubles with running 10w30 in thier transmission.

Are you telling me ATF is bad in a transmission too, because it is a lot thinner than motor oil or gear lube. Ford and BMW use ATF in thier manual transmissions... I have heard ATF used in the AX series works well too, although I personally am not going to try it.

:-)

Not trying to start anything- but Chrysler says to use motor oil, and I have been for many many years and have had no issues. Many others do the same. I too want to use the right lubricant for my transmission. The right lubricant, in this case is motor oil.

ATF is what is in the transfer case, and it is essentially a transmission...

 

its not about what the viscosity is, its the heat resistance of the fluid and at what temperature the fluid loses its lubricating capability, basically cohesion of the molecules

if you understood the table I posted you would have seen that.

ATF is a high temperature hydraulic oil, keyword there is high temperature.

and for future reference, manufacturers/dealers do not necessarily know or do what is right

 

In this case, crapsler is trying to save money. It'sd cheaper to do a warranty fluid change then, and the trans only has to last as far as the warranty.


A transmission shop (NOT a basic mechanic) will never run motor oil in an aisin manual transmission. I follow those guidelines...I blew three ax5's on 10w30. Switched to the proper fluid, and they lasted me twice as long.

Granted, they blew because of the 260 hp pushing them...but the fact that running the proper fluid got me twice the life speaks for itself.



Side note, the factory owner's manual calls for 75w90 gear lube of gl3 specs. The 10w30 specs didn't come around until 2006, when a tsb was put out saying that that was ok.

That's ok in an NV series transmission. Chrysler made the mistake of backdating it for all 5 speeds. I'm sure the idiot engineer who did that has never looked at an aisin transmission, and had Nothing to do with the design of the cherokee xj.


It is wrong information from chrysler. Call up aisin-warner and ask them what they suggest to run in it. I bet they will tell you that I am right.

 

my haynes manual says SAE 75W-90 GL5?
my chilton manual says SAE 75W-90 GL3?

 

haynes was modified after chiltons, and chiltons was right. haynes screwed up. gl5 has non-brass-friendly addatives in it.


since no one makes GL3 anymore, GL4 is the best solution.

 

ok thanks! good thing i got both manuals!

 

honda also says that you can use 10w30 in there manual trans, pending on the year. the interval is also slightly reduced.


hydrostatic systems and hydraulic systems also call for 10w30 in the hydraulic tank, depending on the manufacture and design of the machine.
10w30 meets the temp req for ISO 22 and 32, and ISO 22 and 32 is common in hydraulic systems. It also meets 75w gear oil partially. 10w30 dosent have the same varances in temp like the 75w.

you blew up the first 3 ax15 because your running that high of horse power through them, and the 10w30 in your trans wasnt engineered to get that hot. the 10w30 got too thin and broke down, causing poor lubrication = failure.

if the trans shops knows what there doing, they will tell you the pro and cons of running 10w30 in the transmission. it wont last as long as the 75w, and most people don't follow the proper service intervals. people will leave it in the trans far too long, and cause damage to the trans. thats why trans shops wont tell you to run the 10w30 in the tranny.

 

first, they were AX5's...the AX15's little sister (I choose sister because they are sissy trannies). An AX15 will deal with that hp just fine.

second. I don't go to transmission shops. I rebuild my own motors and transmissions. I can't justify ponying up the money for something that I am fully capable of doing myself. and no, the fact that I rebuilt them myself has nothing to do with their detonation. I am, in fact, an extremely good home mechanic.

They faild because I went with a TSB that did NOT take into account what SHOULD be run in the Aisin series transmissions. my dad (mechanic for the past 40 years, has worked on everything under the sun) told me all along that chrysler was just plain WRONG.


on top of that, I'm friends with several extremely intelligent mechanics. They do this for a living. they teach themselves how to build things. such as hellicopters, jet boats, dyno's, etc. all of them are very capable of discerning the cost/benefits of what should be run, on top of that, what fluid is even capable of doing the job.


so far, of 7 people I know extremely well....all of which are undoubtedly more intelligent and more capable when it comes to wrenching than yourself, there is a unanimous decision that running ANYTHING BUT a gl4 grade gear lube is an absolutely terrible idea.



so, to everyone reading this thread...do as chrysler re-decided in 2006 (YEARS after they introduced the ax15, and certainly many years after they'd even bothered testing fluids on said transmission) if you wish. but fact is, before that TSB went out, people ran the proper 75w90 gl3 or gl4 grade gear lube in their ax15's, and never had an issue with them.

-Pat

 

First: AX5 or AX15, it dosent matter. once a fluid breaks down, it dosent provide proper lubrication. I dosent matter what kind of trans, eng, diff, t/c or whatever.

Second: i have no doubt in your ability in rebuilding engs or trannys, i know several very highly skilled self taught mechanics with little or no formal training.

I have never worked much on chrysler products, and aside from my jeep and plymouth, i wont ever, ever, ever plan on working on them. i dont follow the TSB, i dont know how there engineering department conducts test and PART OF THE REASON I JOINED THIS FORUM.... IS TO LEARN THESE THINGS.

I dont think you know me personally, or stalk me, but i have a hunch that all my TEREX, JOHN DEERE and BOBCAT training in addition to my HEAVY EQUIPMENT TECH license makes me more than qualified to read a viscosity chart CLEARLY stating that 10w30 partially meets the temp range of 75w gear oil.

10w30 will work as a substitute for 75w, but it isnt long term solution. It isnt designed for a wide range of temp as 75w. THE PROOF IS ON PAPER.

And this isnt the place for personal attacks. Grow up kid.

 

With all this controversey, I hate to interject something but a lifetime of shifting gears and thinking about what kind of oil goes in the box I have always known one thing: Gears "shear" oil molecules. That is what wears the oil out. Gearboxes also foam oil unless the oil is protected against foaming. Both of these conditions are what give rise to premature failure. I don't know how motor oil acts in applications where shear and foaming is an issue, but I'm not going to pay the fee to learn the hard way.

Motorcycles with "unit" construction, like HD Sportsters and most JPN and European bikes, combine the trans and crankcase and use the same oil. The choice of oil for this application is more important than for non-unit machines. And the trans and crankcase are designed for a single oil - a motor oil. But it would be mistake, in my opinion, to use motor oil in transmissions that were not designed for it.

As for TSBs...I don't know all the issues. Sometimes the TSB addresses "driveability"...which could mean that some drivers didn't like the sound of gear whine and motor oil dampened it. Or maybe there was some other motivation in play. Who knows.

My theory of engines and transmissions is I go with the OEM recommendation in the owner's manual until the evidence that I should ignore that is overwhelming. So far, nothing has overwhelmed me with any vehicle I own. I put gear oil in transmissions...not motor oil. And I would never substitute 10/30 for 75/90 unless the choice was no oil at all.

 

Mechanical engineer here (graduated from Texas A&M and currently design engineer at NASA) since we are name dropping
the 10w does not full meet the temp rating of the 75w if you look at the chart again you will see that the 75w surpasses it

well then you would probably say, well its not just 10w, its 10w30 so it goes higher, BUT then I would retort its not just 75w, its 75w90 or 140 which goes again even higher

but your post is mostly right