Having some major issues with my transmission

I have a 1998 Sport with 6 cyl. 4L, 5 speed manual trannsmission.

The issue is this...at seemingly random times its is nearly impossible to shift into first gear. I have to throw all my muscle into it. And when I try for reverse the gears grind loudly. It will go into reverse if i slam it down wicked hard and fast. Neither of these issues happen all the time, but ive been noticing lately that it seems to be more common when i have been clutching alot or driving at highway speeds for a while. It either works like a dream, or im arm wrestling the stick.

Ive been told perhaps its the syhncros (Sp?), or maybe the clutch (which is a bit difficult to press in in my opinion). Most diagnostics (just based on me explaining) guess its the syhncros.

am i screwed, could it be anything else....?

when going into first its doesnt grind, its just really hard to push and then it like goes clunk into gear.

 

What is the mileage? Have you ever had the transmission serviced or fluids topped off?

s

 

146,000 miles are on it. Don't think the tranny has ever been replaced or anything. I have totally flushed the fluids since gettin it. It was doing this prior to changing tho. It really seems to do it more When the transmission had been doing alot of work. I'm at a loss. Could it be the clutch?

 

The problem could be in the hydraulics...Maybe the slave cylinder or master cylinder. are either leaking?

 

x2
Going into first gear, its definitely the clutch master/slave cylinders. When you're not clutching it builds up pressure, when you're clutching a lot, it slowly loses pressure, so you have a small leak somewhere. Try topping off the master cylinder with brake fluid, see of that helps. If not, I would suggest buying a whole new pre-bled assemply. It's a little pricey (close to $300 i think) but it is an easy bolt on replacement.
As for the grinding in reverse, change your transmission fluid (and use 70-90 gear oil). This will help (I'm assuming you have the ax-15 tranny). It is supposed to use gear oil, but sometimes shops don't realize this when they are topping off your fluids and they will put something else in. Also, the ax-15 is notorious for grinding while going into reverse (I just had mine rebuilt, new fluid, new clutch, new clutch master/slave cylinders, and it still does it sometimes). It's okay if it does it once in a while (like 1 out of 10 times) but if it does it a lot its time to check/change the fluid. I've also heard that you can use 10w40 motor oil in it and that is supposed to help, but I'm afraid to try it. If you need to back out of a parking spot and you think its going to grind, you can put your car in gear first with the engine off, then start the engine (while holding the clutch of course). This will save the grinding and save you unnecessary wear on your tranny.
Hope this helps,
Dan

 

My car was 5 spd and it started doing that and it turned out to be the syncro's in it but my slave cylind went out about 3 weeks before that and so I got my tranny rebuilt and new slave cyld and it drives like a brand new car. Although that tranny costed about $1700 to rebuild. But is was a sprots car and I had the tranny upgraded. But I was told by the tranny shop that the moer you drive it when the syncro's go out the more that will end up getting damaged and the more they will have to replace and the more it will cost. If it's a stock tranny check out www.everdrive.com I just bought a tranny off there and it's a great tranny. 3 yr unlimited mile warranty on everything.

 

Try shifting into second instead of first, and see if the problem recurs. If it does, you're probably looking at a hydraulic problem (fortunately, the 1998 AX-15 has external hydraulics.)

If it does not, you've probably lost the synchro ring in first gear. This is likely due to use of improper gear oil - the AX-15 is actually spec'd to take GL-3 gear oil indefinitely, or GL-4 for a limited time. The sulphur EP lube additives used in GL-5 are antagonistic to yellow metals - like the bronze used to make the synchroniser rings. If you're replaced the gear oil with GL-5 and it's been a while, this may be what's happened (you can check by draining some gear oil onto a coffee filter and looking for gold flecks in it - that would be dissolved synchroniser.)

Synchroniser rings typically can only be replaced with a full overhaul. Fortunately, manual transmissions tend to be rather easier to overhaul than automatics!

 

x2 good idea

 

okay here are some updates...

After driving on the highway for about 30 miles and getting off, the deal went like this

difficult to put into first gear (really had to push hard)
difficulty getting into second (not as hard to push as 1st)
difficulty getting into 3rd (just not smooth)

Some things ive been noticing as well, my oil pressure is never above half way on the gauge. and alot of the time it is at about 1/4 on the gauge (ive forget the gauge numbers without going to check (im sure you all know them by heart)). connected to the issue? i have no clue, just giving all the info.

So i checked teh fluid level for the slave cylinder and is full, not leaks or anything (that i can find) but i feel it wouldnt be full if it was leaking. The tranny itself doesnt leak fluid, ive been on top of my fluids game. changed the fluid, just used some castrol (cant remember the viscosity but it was pretty thick). Its what ever the manual called for.

The bottom line, I paid 1700 dollars for this jeep. I love everything about it...except for the leaf springs...dont love those...but i digress...i need to figure this crap out without paying the price of the car for a new Tranny. any advice, leads, or words of wisdom would be welcome! you all have been fantastic thus far.

 

Forget the tranny. You don't need one. It is working fine. The problem is that your clutch is not fully disengaging. All you have to do is figure out why. Generally it is two things. One is you need a new clutch. At 140,000, it might be time. But the more common ting is the clutch master cylinder. When thy start to go, they will not put out enough pressure to disengage the clutch fully. Start there.

 

Or the slave cylinder. Or the line itself in between them is starting to go soft (you'll be able to see/feel that - put a few fingers on the line and have a helper press the clutch pedal down. If the line bulges under pedal pressure, it wants replacing. You do not need the engine running for this test!)

 

Also, I don't know when your putting it into first... make sure that youre at a full stop when you put it in. Mine wont go into first until im at a complete stop (or close to it)

 

It could be the clutch, but doubtful, if its not grinding going into first then my money is on the clutch master/slave cylinder assembly. The oil pressure thing is not related, but not good, make sure you have enough oil in there. My xj stays at halfway on the gauge when idling, and pinned to the top when driving.

 

i have an ax-15 and this is what Ive found

for one if your clutch is worn out then the only problem you could have is slipping in gear.
i think your problem could be one or more things but the master i would think is first and or the slave.
the master can suck air and and work improperly .
if you having trouble going into gears with out grinding then its
one or the other, if its grinding going into gears then its the synchros

if your clutch is not disengaging all the way do to the master or slave then you will get reverse gear grind,
one of the other causes of it is too thin of oil making shifting great but slow trans gear stop resulting in grinding in reverse.
ive found that MTF - Royal purple"is the best fluid to use with a quart of 75w oil to slow the gears down.

 

Worn synchronizers, but i would take care of the low oil press first.