Bolognablake
NAXJA Forum User
- Location
- Franklin Tennessee
Quick question, what's the fluid capacity and recommended oil weight for the AX-15? I don't have a owner's manual.
RedLine Oil said:This GL-5-type geal oil doesn't contain the friction modifiers for limited-slip hypoid differentials. This makes the transmission synchronizers come to equal speeds more quickly, allowing faster shifting and much easier low-temperature shifting. Can also be used in racing limited-slip differentials where weak spring design causes too much wheel spin.
Rick Anderson said:I'm an XJ Noob, so please patonize the questions;
The Haynes Manual (84-00), specifically recommends GL-5 fluid for the Manual Tranny, which it doesn't specify which manual tranny, just manual tranny. I also wouldn't trust the Haynes, well far less than I can throw it, because I can throw it far and often do (I'm still waiting to find a cheap FSM on E-Bay).
On RedLine Oil's website they say about their own GL-5 fluid 75W90NS;
Would using MT-90 be a little tough on the synchros, since it has friction modifiers that synchros do NOT need, and let them slip longer than designed during shifting? This is all assuming that GL-5 is the actual recommended fluid.
Would a 75-90 Weight Oil like Mobil1 Synthetic GL-5 75-90 or RedLine's 75W90NS, might do better, since it Synthetic and most likely does not have the Sulfur additives, and also not have the friction modifiers?
Personally, I've used Redline MTL in my Neon 5Spd NVT-350 and it worked great as well; but that is a tranny that is designed for fluids with Friction Modifiers.
Again all is speculation on something I have very little experience and making some big assumptions.
Bolognablake said:After I posted this I did some searching using diffrent terms and found out that GL-5 is not, in fact, the correct lubriacant. Jeep put the wrong thing in the owners manuals and early shop manuals. They changed it later on, but most places still have bad information. Any GL-3 or GL-4 gear oil will work.
CORROSION PROTECTION
The extreme pressure chemistry used in many gear oils
can be corrosive to brass and bronze used in synchronizers
and bushings. Most gear oils are corrosive at
temperatures of 200°F. Red Line Gear Oils are non-corrosive
up to 300°F and the MTL® in excess of 375°F. A
corrosive gear oil can shorten synchronizer life by half
and can also contribute to rust problems.
MTL® - Manual Transmission/Transaxle Lubricant.
A 75W/80W GL-4 gear oil which is designed for manual
transmissions which require 75W or 80W GL-4 gear oils,
motor oils, or most special synchromesh fluids. It provides
low temperature shiftability equal to an ATF, yet
will not thin out or shear at high temperatures and provides
the substantial gear protection of a GL-4 gear oil.
The higher synchronizer coefficient of friction allows
faster upshifting and downshifting and the lubricant is
non-corrosive to synchros and bushings.
MT-90 - Manual Transmission/Transaxle Lubricant.
A 75W90 GL-4 gear oil which is designed for manual
transmissions which require 75W90, or 90 GL-4 gear oils
or motor oils. Uses the same chemistry as MTL® , but is
a 90 WT in order to satisfy certain manufacturers which
recommend SAE 90 GL-4 gear oils.
TRANSMISSIONS - MTL® can be used in most manual
transmissions and transaxles for both street and racing
use unless the manufacturer requires the additional protection
of an SAE 90 or the extreme-pressure protection
of a GL-5. In those situations the MT-90 (GL-4) or
75W90NS (GL-5) will provide good shiftability and synchro
compatibility and extra gear protection.
LightWeight Gear Oil can be used in transmissions calling
for a 75W or 80W GL-5. 75W140NS will provide
greater high-temperature viscosity, reducing gear noise
and rattle. D4 ATF can be used where the manufacturer
calls for an ATF as the D4 has GL-4 gear protection
and provides the best low-temperature shiftability.
Haynes? That's your answer right there. Anyways IIRC the sequence of events was as follows. From jeep the requirement was GL3 for AX15, then for one year they said GL5 and then they went back to GL3.Rick Anderson said:I'm an XJ Noob, so please patonize the questions;
The Haynes Manual (84-00), specifically recommends GL-5 fluid for the Manual Tranny, which it doesn't specify which manual tranny, just manual tranny. I also wouldn't trust the Haynes, well far less than I can throw it, because I can throw it far and often do (I'm still waiting to find a cheap FSM on E-Bay).
This could explain the mixed results with GL-5 Fluids. In the prevous posts about GL-5/GL-3 issue, some swore that they've used the GL-5 for years and never had a single problems, others used Mobil1 Synthetic or other GL-5 and their synchros were garbage.CORROSION PROTECTION
The extreme pressure chemistry used in many gear oils
can be corrosive to brass and bronze used in synchronizers
and bushings. Most gear oils are corrosive at
temperatures of 200°F. Red Line Gear Oils are non-corrosive
up to 300°F and the MTL® in excess of 375°F. A
corrosive gear oil can shorten synchronizer life by half
and can also contribute to rust problems.