I have a 1991 3.0 liter Aerostar (100k) with manual transmission. Periodically the clutch does not fully disengage (initial start-up in the morning) and I have difficulty engaging the transmission (first or reverse). The clutch does not slip, and shifting is normal 2nd through 5th (although not as smooth as my 91’ Ranger).The master clutch cylinder appears perfectly normal, never having to add fluid. I suspect my problem could be with the slave unit. I have bled the system a couple of times to no avail. I looked at a slave unit at the parts store and was surprised at its size. If indeed the slave unit is the culprit, is transmission removal required?
To replace the slave cylinder in this vehicle requires the removal of the transmission. However, I don’t believe that this is the problem. If the slave cylinder were the problem it would leak and the fluid level would drop and you would see it dripping from the bell housing. Instead, I believe you have a clutch master cylinder that’s leaking internally. When this happens, the cup seal inside the master cylinder allows fluid to bypass it. This results in little or no hydraulic pressure to the slave cylinder. Then the clutch doesn’t fully release and this results in gear grinding when trying to shift into gear.
Replace the clutch master cylinder and then bleed the system. Because installing a slave cylinder in this vehicle is no picnic.