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Need help with manual trans!!!

2K views 10 replies 7 participants last post by  woody109 
#1 ·
I recently purchased a 1999 Wrangler Sport, 4L inline 6, 5 speed. I knew before hand the transmission needed some work. When I test drove it, it wasn't so bad. It still isn't so bad and is drivable, I'm just a perfectionist when it comes to my vechiles. This is my first Jeep. Anyways, 4th gear grinds and it's hard to get it. 3rd will grind a lil if you shift too fast. And 5th will grind sometimes, also its hard to come out of 5th, you have to muscle it. Not too bad though, but it's not normal.
Could anyone help diagnose my problem? I'm thinking it's the synchronizers, but I'm not totally sure.
thanks for any and all help!!
 
#3 ·
Well, your AX-15 transmission probably needs an overhaul. But since you bought it used, no telling what lubricant the previous owner put into it. So it wouldn't hurt to drain it and refill it with a known excellent quality gear lube that perfectly meets its specifications... Redline MT-90 available at a discount from www.summitracing.com. It can't hurt to try it first before pulling the transmission. :)
 
#4 ·
Have you ck'd the oil and level? My 91 was behaving the same. Oil was old and only half full. Drained and refilled( I'm using Mercruiser High performance gear lube) , took a few miles but now it shifts much better and is a lot quieter.

It could be the syncros, but I prefer to go for the simple solution first. I don't change parts just to change parts.
 
#5 ·
It's currently at 151k miles. Motor is solid just having problems with the gears. I'll definitely check the oil and flush it if need be. I always assume the worst.
Also, I was driving the other day and I was wanting to shift up and it wouldn't go into 3rd, so I tried down shifting and couldn't get 2nd. As I slowed down more I tried 1st and still no luck. Couldn't hit any gears, but when I came to an almost complete stop it let me into 1st, no troubles heading back to the barracks, but I haven't drove it since.
 
#6 ·
Check the clutch master cylinder and see if your fluid is low. If it is hard to shift into all gears, it sounds like your clutch is not completely disengaging. Your clutch master or slave may be going out. Look for leaks on the firewall, both under the hood and inside under the dash. Then look for a leak on the slave mounted to the trans.

But you should change out the trans fluid anyway so that you know it has the right fluid and it's fresh.
 
#8 ·
Remove the fill plug, the top one. If a little lube seeps out, it's full. If nothing seeps out, stick your little finger in the hole and angle it downward. You should get at least a drop of lube on your finger. If not, your tranny isn't full. As advised above, drain it and refill with a good, spec meeting lube. When refilling or adding lube, add it until it begins to seep out of the fill hole.
 
#10 ·
The fluid seems fine, was also full.
I'm feeling like it's the synchronizers or linkage. My dad had the same problem with his Ford Ranger, and I believe they replaced the synchros. But I also think it might be clutch. At times I'll have the clutch pressed in and it won't go into any gear. I'll release the pedal and press it all the way down again, and problem solved. For the moment being.
I also don't know how to reply to individuals on this forum. So bare with Me guys. lol
 
#11 ·
The clutch may need to be bled. Much like the brake system. If there is air in the lines it won't disengage properly. Can't compress air the way it can fluid. Lots of info on the forum. Try the search feature. Also could be a bad slave cylinder but try to bleed it first
 
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