Hey folks, I don't have a XJ but my son in college does, a gift from his grandfather. He's having a problem with it and I am long-distance skeptical about what the mechanic in his college town is saying. And I think we can fix it ourselves. So, I wanted to ask you all.

It is a manual transmission, 4.0L six, two door XJ, 4x4, 1990.

The clutch won't disengage so the transmission can't be shifted. I told my son to check the clutch master cylinder reservoir level, he reported it was low, so the Jeep went to the only mechanic I could find in Eugene OR who works on XJs. That shop fixed a bunch of other things that were wrong with the Jeep - all of which were things it did need - but didn't do anything about the clutch fluid issue besides checking the master cylinder for leaks (none) and refilling the reservoir. So he's having the same issue. This time he knows to refill the reservoir, which restores normal function but only for a few days. Okay, the Jeep went back to the mechanic who now diagnoses "The clutch slave cylinder is leaking. Requires trans removal to replace" and has quoted $2,000 for the work.

I've never heard of a clutch slave cylinder whose replacement requires transmission removal. I looked at some older posts here that indicate clutch slave cylinder replacement is two bolts and some bleeding, with no mention of needing to remove the transmission.

So I am thinking of having him top up the reservoir and drive the car from college (Eugene) to home (Portland) and he and I will replace the clutch slave cylinder in the next couple weeks.

I've worked on cars a decent bit, have tools and a lift - but have never worked on his XJ. So, is this going to be as simple as it seems? Or is the mechanic right?

 

The mechanic is correct. On a 1990, the slave is inside the bell housing and slides onto the input shaft. Crawl under and look on the drivers side for the hydraulic line running into the bell housing instead of an external slave cylinder. Later years, 1992 I think, have an external cylinder and a crank arm. If you're going to pull the trans, I would consider doing the clutch while you're in there.

It is possible to convert to an external slave, but you need a donor bellhousing and a later model input bearing cover. Here are some pictures of converting the ax5 used with the 4-cyl, but essentially the same process for the AX-15. https://www.motortrend.com/how-to/16...inder-upgrade/

Also, do not use GL-5 gear oil in the trans. The EP additives in GL4 or GL5 gear oil will eat the brass synchros and shift poorly. Redline MT90, synchromesh, or synthetic 10W-30 motor oil all work well and are all safe for yellow metals. The dealer are putting in 10W-30 nowadays.

 

If the slave cyl is leaking, there's a good chance the fluid has contaminated the clutch. Since you'll have it all apart, I suggest you replace the whole clutch while you're in there.

 

Oh, that’s a bummer - but good to know. Thank you everyone. I’ll follow this advice.

I’ve replaced clutches and R/R’d transmissions, but right now I’m scrambling to finish a DIY kitchen remodel before my wife’s patience expires. Not a good time to get into my son’s XJ!