Forget the brands and the whatever else. Look at the specs. The AX-15 as far as I know, requires a GL-4 oil. They don't work for shit with a GL-5 oil. Mine had some unknown stuff in it when I bought it...likely GL-5 because it didn't shift for shit, so I replaced with it a GL-4 oil....I used Amsoil, because it was on the shelf at my local parts house. If redline was there, I would have used that...but the brand DOES NOT MATTER, as long as the product meets the specification. After putting 100 30 or so miles on my shitbox with the new gear oil...damn thing shifts like butter...wife even stopped complaining about it. I used to road race a VW and had a pile of very stout (relatively speaking) 020 transmissions with different gear ratios...all of which were gone through after every track day because I was told they were the weak link....they needed a GL-4 oil, and I ran redline, because it was free at the time. Then when it started costing money, some guy gave me a 5 gallon bucket of no name GL-4 oil so I started using that...it worked just as well. Ignore the name on the front of the bottle, pay attention to the specs listed on the back of the bottle...that's the important info and the only info that matters.
Manual transmission oil facts
- Thread starter PatMc
- Start date
I used Pennzoil Synchromesh in mine, it made a world of difference compared to the old stuff. I am due for a flush, Ill probably put the same stuff back in since it is readily available off the shelf in my part of town.
The difference between GL-4 and GL-5 is just an additive to be safe to use with soft metal (brass, bronze) in the gearbox. -5 will cause the soft metal to wear and dissolve over time. And I can tell you with 100% certainty that you are right 99% of the time. But in my case switching to Redline made a huge difference in the 6 speed. Huge. Now I can find reverse. Now it will easily go over to the 5/6 rail. Neither was happening with several other brands. Not gonna fight you. Not gonna argue with you. Just telling you that in every other gearbox and diff I've seen you are right. But in this one instance I know that switching to the Redline did make a huge and quick improvement in the gearbox.
I have to disagree. While I agree with you when it comes to motor oil, I have noticed significant improvement moving from the Mopar gear oil to Redline both in cold weather and normal operating conditions for my NV3550. The 1-2 shift is much improved, it's easier getting into 1st, and I no longer have stickiness in 2nd when shifting to 3rd. Maybe the AX-15 is less fussy about oil, but at least for the NV3550, the brand does make a significant difference.
This applies to engine oil as well. The brand doesn't matter one bit. If the oil meets the specs, that's the only thing that matters. Some people get too attached to brand loyalty (which is the goal of successful marketing) and assume nothing else can be better.
Subscribed.
I too used to dabble in the VW aircooled and water-cooled scene a long time ago and we even made use of Redline and synchromesh(the Pennzoil one) and shockproof mixed together in different ratios to get it just "right". The 020 and 02M transmissions in particular. Heck I still have a few quarts left of some tri-blend that seem to work alright
The AX-15 from what I have been reading is a different beast. I don't know what is currently on mine as I just purchased the Jeep a few months ago, but I will use some quality oil to run for a few months, then go to a proper GL4, maybe even the MT-90 since it does have a lot of backing in the interwebs(hard to argue with popular vote)
I too used to dabble in the VW aircooled and water-cooled scene a long time ago and we even made use of Redline and synchromesh(the Pennzoil one) and shockproof mixed together in different ratios to get it just "right". The 020 and 02M transmissions in particular. Heck I still have a few quarts left of some tri-blend that seem to work alright
The AX-15 from what I have been reading is a different beast. I don't know what is currently on mine as I just purchased the Jeep a few months ago, but I will use some quality oil to run for a few months, then go to a proper GL4, maybe even the MT-90 since it does have a lot of backing in the interwebs(hard to argue with popular vote)
Only most GL-5 gear lubes are bad for the AX-5 and AX-15 transmissions which is due to their use of sulphur-based additives for added R&P gear protection which is what gives the gear lube its GL-5 label. Sulphur-based additives are harsh on the yellow metal (brass) gear synchronizers. But there are indeed some GL-5 gear lubes that are just as good as a GL-4 because they use alternative non-harsh additives that give it the GL-5 rating. If the back label of the GL-5 gear lube says "Safe for yellow metals" then it's ok for use in the AX-5 and AX-15 so long as it's a 75W-90.
But even so I'd still stick with Redline MT-90 for the AX-5 and AX-15 transmissions. MT-90 is a fully synthetic GL-4 75W-90 which is well known to be a superb lubricant for those transmissions.
Probably the last "correct" gear lube I'd ever use in the AX-5/AX-15 transmissions is Synchromesh from Pennzoil or GM. Yes it meets the specs but there are more bad reports on it than good reports... not to mention Synchromesh from Pennzoil/GM is a conventional oil which isn't a good choice for a transmission that sees cold weather.
But even so I'd still stick with Redline MT-90 for the AX-5 and AX-15 transmissions. MT-90 is a fully synthetic GL-4 75W-90 which is well known to be a superb lubricant for those transmissions.
Probably the last "correct" gear lube I'd ever use in the AX-5/AX-15 transmissions is Synchromesh from Pennzoil or GM. Yes it meets the specs but there are more bad reports on it than good reports... not to mention Synchromesh from Pennzoil/GM is a conventional oil which isn't a good choice for a transmission that sees cold weather.