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Discussion Starter · #1 ·
Hey Everyone!

I am hoping to get some help with my sudden hard shifting problem. My YJ has 175,000 kms on it. Have had it for about 6 weeks, with no problems whatsoever. Yesterday, I dropped the tank to install a trailer hitch, and the next time I drove it I ran into some hard shifting. It was very hard to shift into any gear. Once it warmed up after driving for about 10 minutes, it was fine. I checked the clutch fluid and it was full. I drove it about 2 hours home from the cottage with no problems at all, but this morning on the way to work, there it was again.

With the engine off, it seems to go into any gear without problems, except for reverse. I had to pull pretty hard into reverse. With the engine running, it just grinds when I try to shift into reverse, and is really tough to get into any other gear.

Any help diagnosing would be immensely appreciated.

Thanks!!
 

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The reverse in our YJ's is unsycronized, it's easier to get in reverse by pump the clutch a few times or driving forward slightly.

As far as the shifting in other gears... what's the state of your transmission fluid.
 

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Discussion Starter · #3 ·
Thanks for the quick reply IRQ! I am going to check out the transmission fluid situation after work today and I will report back with the results.
 

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It sounds like clutch adjustment to me. I don't know if the 1994-1995 hydraulic clutch is adjustable or not. If you have to change the master/slave assembly luckily it's available as a pre-bled assembly.

IRQ is correct in asking about your trans fluid. The first thing I would do is change the transmission lube.
Bear in mind that even if the Factory Service Manual recommends GL5 trans fluid, that the GL5 fluid can harm the brass syncros in our transmissions. If you want 90W gear lube, you need to find one that states on the container "Yellow Metals safe". Some premium GL5 fluids may have that designation. An alternative is to use 10W30 motor oil.
There was a chart posted on this forum in a thread that discussed transmission lube that showed 90W gear lube has almost the same viscosity as 10W30 motor oil. It appears that the two different fluids are rated by different standards.
I was lucky enough to find some GL3 trans fluid when I changed mine. My current transmission is a BA10. I have an AX15 that I'm rebuilding and when I install it I'll use 10W30 motor oil and STP.
The STP is my choice and not necessarily recommended by anyone other than STP.

It's a good idea to change all the fluids as soon as you buy any 22 year old vehicle. In all probability, the transmission fluid, the front and rear differential fluids, the brake fluid and the clutch fluid have never been changed.
I suggest that before winter hits that you flush your cooling system and install new coolant along with a new MOPAR thermostat. If you keep a record of when each service was done, you'll have a baseline of when to perform each maintenance service.

Good Luck, L.M.
 

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Discussion Starter · #5 ·
Excellent thank you LM! First order of business is to change the tranny oil. If that doesn't do it, I see I can get a new master/slave cylinder, pre-filled, pre-bled for about $140 shipped. Would that be a rational next step?
 

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Excellent thank you LM! First order of business is to change the tranny oil. If that doesn't do it, I see I can get a new master/slave cylinder, pre-filled, pre-bled for about $140 shipped. Would that be a rational next step?
Possibly... I know when I changed my 20 year old slave the shifting was much more pleasant.

The Mopar one is still available #52104113

Some tips for the install:

Don't break the plastic tip holding the plunger, it's meant to be installed with it on.
There is a clip holding the plastic tubing to the firewall, be careful removing this as you will need it for the new one.

As Luckymac stated you want to use oil that is safe for the brass syncros, there are a few choices available.

Amsoil GL4 75/90 (I use this) Link
Redline GL4 75/90
Synthetic 10w30
GL3 if you can find it?

To understand what GL5 does to brass this PDF is a good read Link to PDF
 
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Discussion Starter · #9 ·
Quick Update: I ended up having to work past midnight last night, so needless to say I wasn't able to get the fluid changed. I did however, top up the clutch fluid before I drove home last night. It did take a small amount in the reservoir, perhaps an ounce or so, and seemed to shift much better on the drive home (about an hour), but not perfect. I checked it again when I got home, and it was still full to the brim.

Is it possible / likely that I have a slow leak in my clutch hydraulic system somewhere, causing my clutch to not fully disengage? If so, would it be possible to fix the leak, or simply better to replace the master and slave cylinders? For under $150, perhaps I might just as well. It doesn't look to be a tough job from what I have read online.

Thanks!
 

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You should change the tranny fluid anyhow, so I suggest that you do that first before spending any time or money on the clutch. If that cures the hard shifting, you're done.
If it doesn't cure or dramatically improve shifting, then bleed the system.
Then if things aren't better, I think your next step will be to replace the master/slave.

Good Luck, L.M.
 

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Discussion Starter · #11 ·
Yes, I'll definitely do that first. Can the external slaves still be bled? I thought I read somewhere that they couldn't.
 

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On my S10 I had a heck of a time bleeding the clutch and they are notorious for being a bear to bleed. I took my MytiVac with a narrow tip and stuck in the down into the hole at the bottom of the reservoir that the line to the slave cylinder goes to. Then I put about 20 inches or so of vacuum on it and watched the air bubbles come up the tube. I worked the pedal slowly from the top to the floor a few times also. When you disconnect the tip from the hole leave the vacuum on and just pull it up out of the hole. The vacuum you created will suck the fluid into the line and you won't create any air bubbles.

I had to do this a couple of times but it eventually gave me a great pedal that I have no problems with to this day. I used this technique on my brake master cylinder after I bench bleed it and install it to make sure all the air is removed from the system. May not be the "official" way to do it but it works for me. Good Luck.

PS: if it won't hold vacuum then you know you have a leak in the system somewhere.
 

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Discussion Starter · #13 ·
Hey Everyone - thanks again for all of the replies. I found them very informative.

So over the weekend I got down to business. First thing I did was change the transmission fluid. I used 10w-30 Lucas Synthetic. I fired it up and drove it around the block, and it got stuck in gear within 5 minutes of driving.

I went out and picked up a new Pre-Bled, Pre-Filled Master and Slave cylinder by Dorman. https://www.amazon.com/Dorman-CC649002-Combination-Cylinder-Assembly/dp/B001T9QOLA

That's the same model, but it costs nearly $400 in Canada. I managed to get it for $250 but still felt a little ripped off.

Anyway, it took me about 30 minutes to install, and immediately my YJ shifter better than ever. I drove about 8 hours over the weekend with no problems at all.

Thanks again for your insight! I'm going to be doing some frame repair in the next couple of weeks so maybe I will start a thread on that.
 

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Discussion Starter · #14 ·
Oh, and I can confirm that my '94 has no bleed screw anywhere on the slave cylinder, nor did the new replacement that I put in. Apparently the external slave cylinders are not meant to be bled, just replaced.
 
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