sorry...didn't mean to name drop, i just don't like being called stupid. I don't believe that personal attacks are called for. Your right about the 10w30 not meeting the full temp range of 75w, and that's what i was implying. I guess i wrote it out poorly (long day at work.... )

10w30 is a usable solution, just not a long term one. Its generally a good idea to go with what the OEM recommended. It being 75w, 10w30 or whatever.

Oh and that has to be a killer cool job, btw. Designing spacecraft to replcae current ones. I might be just a little jealous.

 

Wow, sifted through that whole post and just to stir it up some more.... first off a little back ground, I have been a chrysler tech for 20 yrs and yes I have put 10w30 in manual transmissions with no issues. The chrysler tsb that was reffered to was not a mistake or genaric it was to address shiffting issues such as high shifting effort in cold ambient temperatures. Just my .02c

 

10w 30 in a gear box? are you ****ing kidding me? i'm so happy now that i've never taken my jeep to chrysler...
Unless you live in Alaska, involute helical gears and hypoid couples are designed to have a sliding contact point on the surface of the teeth. The reason of this is to reduce noise, but the sliding generates more heat than normal gears, therefore 80w 90 oil is required to lubricate and dissipate the heat buildup. If you put 10w 30 oil in a gearbox the lubrication will not be able to dissipate all the heat, and as soon as you hit highway speeds for a couple of hours the first thing you toast are your synchromesh cone clutches, and when the hardened surface of the gear teeth is worn down, goodbye tranny..
I mean, why do you want to take the risk, i use 80w 140 in my diffs, we are constantly in heavy duty mode when we hit the trails.
Ah i forgot, i'm a material engineer and i design marine engines and inverters (gearbox), hi collegues.

 

its not that cool, having to answer to politicians while trying to execute long term plans is like trying to drive a car with severe alignment issues

its pretty funny if you take a step back, engineers and scientists (people driven by absolutely and logic) being managed and funded by politicians (people who avoid anything concrete and have absolute no concept of logic)

 

I hate to dredge this apparently hot issue back from the dead, but after a ton of searching, I have yet to find the answer to my question. I have an ax15 and I put Royal Purple 75w90 in it. I understand that it is rated gl-4 and gl-5. It has ran fine for the last 5,000 miles and roughly two months. No problems. Should I expect it to destroy my tranny since it is rated for both? Should I go ahead and switch it out, or am I fine to drive on?

 

switch it to gl4 only.

most gear box fluids are gl4/5 now...and none of them are safe for the synchros in an ax15.

 

I'm tring to wrap my head around this, Every manual trans in cars and light duty trucks have brass syncos but no one makes oil that is safe for yellow metals anymore? or i should say very few make yellow metal safe oil.

I run gl4/5 cause it was all i could find and ive already had worn syncos so i'm use to double clutching 2nd and 3rd and I havent noticed a change from running gl4/5. Iagree running motor oil in the trans is not the best idea, ive noticed my jeep is a pain to get into 2nd in winter but its usually a pain to get into 2nd all the time

 

My transmission runs absolutely fine. The only problem I can tell with it is that it doesn't like going into reverse. My cure for that is holding down the clutch when I start it, keeping it held down and shifting into reverse or if it's already running and I have to back it up, I hold in the clutch for 2 or 3 seconds and then put it in reverse and it doesn't grind that way, either. Other than that, I have no problems. I live in a very cold climate (Colorado's Rocky Mountains), and it's not difficult to shift, at all.

 

You know you can shift into 3rd then into reverse, Try it out it works pretty well. I guess ppl call it the truffle shuffle lmao


i dont know what ppl call it but it works

 

haha the ax15 shuffle!

 

You are getting a lot of bad advice and it has you worried. In fact, there is so much bad advice about oil on the internet it is starting to freak me out.

The idea that oil can and would be be made that is specifically designed to stealthily destroy the transmissions owned by the unwary (i.e., any transmission which has "yellow metals" in it) is nonsense. There is probably oil out there that does not do a great job protecting brass but that does not mean using it will result in the end of life on earth as we know it.

Read your owner's manual and buy whatever oil it says to buy. If that oil no longer exists, buy what superceded it. I don't know what is in an AX15 but one thing I am absolutely sure of, there is a transmission friendly oil on the shelf at Tractor Supply. If there wasn't, about one million farmers would rise up in revolution.

If it has gears and brass syncros (and almost every manual transmission on EARTH has gears and brass syncros) buy tractor oil if you can't find anything with precisely, exactly, specifically, the EXACT oil spec'ed in your Owner's Manual.

And if that don't work...pour ATF in it. Or 10w30. Or gear lube. Or that stuff you get all over your hands after shaking hands with anyone that lives in Washington, DC.

And if your syncros are already dodgy, no oil on earth will save them. Prowl craigslist and call JY's until you find a replacement.

Where did all this "yellow metal" stuff start anyway?

 

Well i was just wondering on the oil cause ive been so accustomed to using syncomesh in my GM trannys but hate paying the price tag, i'm just going to stick with the 75w90 oil ive been using for the last several years.

At the time i got this AX15, it was the only one i could find in MI. Now i collected a few 2wd and junky 4x4 ones from here and there that i'm going to use to rebuild a nice AX15 for myself once i get some of my damn taxes back

 

http://www.amsoil.com/storefront/mtg.aspx

cured shifting issues in both my Unimog and my 400whp Nissan 240sx... its worth the money!

 

I'll book mark that, Its alittle pricey to put in my pos trans but if i spend the money to rebuild it i will put good oil in it

 

pricey? What does it take to fill it? 2 or 3 quarts? Its worth it, even on a "pos" one. My Unimog would suddenly try to move its self when I would leave it to warm up. Before this stuff, I had to keep a dip stick heater in the tranny.... Now the Jeep is a lot less temperamental.