Ongoing tranny or clutch issue

94 4.0 with AX-15 manual tranny.
Problem was;
Grinding when upshifting to 2nd or 3rd, but never downshifting. Happened all of the time so I would have to double clutch or shift slowly. Thinking syncros perhaps or maybe just needed a gear oil change.

Problem now;
Changed gear oil in it, replaced with Valvoline 75w-90 GL-5. Now it shifts great when warm, but when cold it will grind like mad going into 2nd and 3rd and 1st can be a downright pain! 75w-90 is what the Haynes/Chilton calls for, yet now I see stuff on the net saying GL-3 needs to be used in this tranny.

Solution;
???

which oil to use in the ax-15 has been one of the most thoroughly debated topics on this board. search.

if it is your synchros, nothing will really fix it. i drove around with a really crunchy third gear until i had to go straight from 2nd to 4th. had the tranny rebuilt and found out that the synchro was in two pieces and all of the other ones were close.

here are some things to try, if it isn't your synchros then these should help, or at least narrow down the problem.
bleed the hydraulic system. this is very easy and might just eliminate the problem.
if you have the external slave cylinder (i bet you do), then you might be able to make it extend farther and therefore disengage the clutch more thoroghly by lengthening the tip of the pushrod. i did this to mine when i knew it was the synchros. it helped some, but if you have a real problem, then you need a real solution.

someone chime in if any of this is way off

hope this helps,
dan f.

Both Jeep dealers in town tell me that GL3 needs to be used in the AX15, yet every transmission shop and oil change place tells me their manuals say 75w-90 GL5. And they say that information comes from DMC!! Plus, my Chilton's and Haynes manuals say GL5 as well. What the heck :huh:

Aha, just found my factory Jeep owners manual... it says GL5! Why then do the Jeep dealers tell me I must use some special GL3 that they sell for $15 a quart? :twak:

redline 75w90ns is what I use In my AX-15 and it seems to work well. It gave me alot smoother shift.
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.

Dino GL-5 will make your transmission grind. When I bought my 95 it had a noisy transmission and shifted poorly. I put the recommended GL-5 in and it got worse, with symptoms just like JKTXJ's, including almost impossible shifting when cold. I had trouble finding GL-3 around here, and auto parts people gave vacant stares when I emen mentioned GL-3, so I tried Valvoline Synthetic GL-5, and it's been fine for nearly a hundred thousand more miles, quieter and shifting better, and working well even when below zero.

I know it's GL5 still, and probably not kosher, but the thing now has 210 thousand miles on it, so I don't think you can say it's going to die young.

JKTXJ said:

Both Jeep dealers in town tell me that GL3 needs to be used in the AX15, yet every transmission shop and oil change place tells me their manuals say 75w-90 GL5. And they say that information comes from DMC!! Plus, my Chilton's and Haynes manuals say GL5 as well. What the heck :huh:

Click to expand...

Search search and one more time search. This is one of the most beaten up topics!!!
A quick recap: from what I have seen and remember it's always been GL3 but then one year the manual gets release with GL5 and then next year gets release with GL3 again. My FSM and my manual (for a 98) say GL3.

Someone here mentioned before that during whichever year they swiched the synchro material that requires peple to use GL3 as it's less abrasive to them, but I don't think that there is an exact and definitave date for that switch (even if it occured... my theory is that they always were happier with Gl3). In any case transmission and oil change places will not know: they only know that it requires 75w-90 and GL5 is what is cheap and available. Chiltons and Haynes have been proved wrong before on many things (including Torque specs being too high) so I wouldn't trust them at all and wouldn't even bring them up as an authoritative source of any kind

Anyways if it's synchros that went... guess what.. you should have used GL3 And yeah I know that there are people using some synth variations of gl5 that are supposed to be safe for GL3, but you know what? at the cost of tranny rebuild or replacement I will pay $15/qt (you can get them to charge you less actually) just for the piece of mind.

Drove to the Jeep dealer today and talked to the Jeep tech. He said they use 75w-90 GL5 in the AX15 when they service them. I told him that the parts dept told me it has to be MS-9684, which is a GL3. They were like, huh? I went to Parts and asked them where they find that info. The guy photocopied the page for me, the stuff is actually called "Mopar Manual Transmission Lubricant AX-5 AX-15". Service tech said, "We don't use that stuff." He acted like he didn't even know what it was. I then called Jeep Customer Service up. After being transferred here and there, they told me... "I don't know, use whatever your owners manual says." So, the moral of this story; Use whatever you like because Jeep has no idea what should go in that tranny. Good luck! I'll try the Valvoline synthetic that was recommended.

JP

You can find the AX-5/AX-15 stuff here by the way;
http://www.americauto.ru/content.files/chemicals.pdf