[Fjguercio]

Originally Posted by JeepRide

Do not use 80w90 regular gear oil it will eat your brass syncronizer. You need Red Line MTL gear oil or pennzoil synromesh

X2.... I agree with JeepRide, recently went looking for 85-95w GEAR LUBE and everthing is GL5 in the stores. GL5 Gear Lube eats yellow metals and is not good for trans or transfere cases. I had GL5 installed for a few months and my syrncros started rattling and shifting was getting harder.

MY 1979 FSM and Chilton CJ/Jeep Book says to use 85-95 Gear Lube in several places and one place says to use GL4 for the transfer case. Another CJ user told me of this and went looking. I found GL4 avail at NAPA in gallons for $15 and it says will not eat yellow metals on the side of the package........ I also found a good article on the Amsoil web site about GL5 vs GL4. Some of the synthetics were also corrosive to yellow metals.

If I were you guys I would warm up and drain the trans and transfercase. The GL5 if use is corrosive and does not have the lubrication properties to make the syrncros work properly. Change to the Napa GL4 and see if it starts to make a difference. GL4 is not easy to find you will have to look/call on phone to find it. I did in mine with 1978 CJ7 with T18b trans and Dana 20 transfere case and it made a big difference after changing out the GL4 I just put in a few months prior.

Symtoms would be would not shift correctly into and out of gear because the syrncrose are not lubricated and stoped correctly in addition to the corrosion.

Regards,
Fred

[Fjguercio]

GL5 is ok for pumkins but not the Manual Transmission and Transfer Case.

[JWFokker]

I just got a response from Amsoil that the 75W-90 Severe Gear oil, which is GL-5, is formulated to be yellow metal compatible and is okay for use with the AX-15 transmission. No worries about it eating the brass synchros, so you can add that to the list of options. Now we just need some kind of comparison between the Amsoil SVG and the Redline MT-90 and MTL.

[bigbike]

I was wondering about Amsoil actually can someone expand on it?

[Ridin' Around]

Originally Posted by bigbike

I was wondering about Amsoil actually can someone expand on it?

I put an email in to Amsoil tech yesterday on JWFokker's behalf, after a PM conversation we had. The Word from Amsoil is that their GL-5 gear oils are OK to use. The synthetic formulation they use will not cause damage to the "yellow metals". So follow the recomendations they put in the Product Application guide without fear. Thanks for the question.

[440_Magnum]

Originally Posted by nexus42i

I was feeling particularly motivated this evening so I ran to the store and picked up some 80w-90 to change my transmission fluid and front and rear differential fluid. I put it up on the lift for the first time and took a look at the transmission. I see the drain plug on the passenger side towards the bottom of the transmission, and I see what I think is the fill hole towards the top, but the question is, how do I actually fill the thing up? Looks like there is just enough space to get the plug out, am I going to have to pump it up using a small hose?

You can put a hose over the tip of the bottle your gear oil comes in and squeeze it up. Its not too bad.

By the way, DO NOT put the same type of gear oil in the transmission that you put in the differentials. Diffs need hypoid gear oil (API GL5) at least, and limited slip additive if you have a limited slip differential. GL5 and limited slip oils used in a transmission will be "too slippery" (not really, but you an think of it that way- it has to do with the static vs. dynamic coefficient of friction of the fluid) for the synchronizers in the manual trans.

What you need for a manual trans is a fluid with excellent gear lube qualities, but without the friction modifiers for hypoid gears, such as a GL3 or GL4 fluid. They make specialty fluids for manual trannies (Redline MTL or MT-90, for example... Royal Purple also makes them) and these are an excellent choice. Shifting gets *much* better with these fluids, especially if someone has ever allowed GL5 oil to get into the tranny. GL5 won't actually harm the synchros, but can lead to grinding gears since the syncrhos will take longer to do their job as you move the shifter lever.

[440_Magnum]

Originally Posted by bigbike

I was wondering about Amsoil actually can someone expand on it?

Its non-API certified, and its sold through a pyramid scheme. 'Nuff for me to avoid it like the plague. Go with Redline, its good stuff. Or Royal Purple.

The Word from Amsoil is that their GL-5 gear oils are OK to use. The synthetic formulation they use will not cause damage to the "yellow metals".

That doesn't make sense, and is not possible. Its either one or the other- its EITHER a GL-5 fluid that has adequate extreme pressure lubricity for hypoid gears like a rear axle, OR its a gear lube with the correct coefficient of friction for syncrhos. It doesn't matter a damn that the oil "won't cause damage to 'yellow metals,'" the point is that if it REALLY meets the GL5 rating then its got additives that will prevent the sychros from doing their job and slowing or speeding up the input shaft quickly during a gear change. Using a GL3 or GL4 oil is the only correct choice for a manual transmission. Unless you want to learn to double-clutch it like a 1930s vintage crash-box all the time.

[Slowride63]

I agree with using only GL-4 lube in the tranny. I have used Pennzoil synchromesh for years now, and the only problem I've had is finding it in my area (small town). As for getting it in the trans, I use a small lube pump similar to the one pictured here...http://www.amsoil.com/storefront/g2039.aspx These are available at most auto parts stores for about $6.

[Ridin' Around]

Originally Posted by 440_Magnum

Its non-API certified, and its sold through a pyramid scheme. 'Nuff for me to avoid it like the plague. Go with Redline, its good stuff. Or Royal Purple.




That doesn't make sense, and is not possible. Its either one or the other- its EITHER a GL-5 fluid that has adequate extreme pressure lubricity for hypoid gears like a rear axle, OR its a gear lube with the correct coefficient of friction for syncrhos. It doesn't matter a damn that the oil "won't cause damage to 'yellow metals,'" the point is that if it REALLY meets the GL5 rating then its got additives that will prevent the sychros from doing their job and slowing or speeding up the input shaft quickly during a gear change. Using a GL3 or GL4 oil is the only correct choice for a manual transmission. Unless you want to learn to double-clutch it like a 1930s vintage crash-box all the time.

I Don't belive that you understand the way Synthetics are formulated. I am am positive that you don't understand Amsoil's marketing. If you would like more info on it please let me know. Until then, I am a dealer that is trying to help out on the forum and answer questions. I also sell products. Where I learned about business that is called capitalism (i buy a product and sell it for profit) not a pyramid scheme. As far as the product it is one of the best on the market, without question.

[roganrogan]

i cant find my fill plug and i think thats my problem all my gears are rouugh and second grinds bad but i dont know how to fill it its roughly drivin through lakes and rivers mud and sand its an 89 cherokee with the ax15 im pretty sure

[grainofsalt]

Here you go rogan: http://www.scribd.com/doc/7057536/Jeep-AX15-Service-Manual-Transmission#fullscreenn