Mysterious 5spd Shifting Problem.

98 2.7 Extra Cab 5spd 4x4 230k miles.

Thanks for taking the time to read this and offer any ideas. I've been digging through prior posts of similar problems and haven't found anything too conclusive. FYI, Im unsure whether it is the original clutch or not.

The PROBLEM:
Hard shifting from incomplete clutch disengagement. It also miraculously fixes itself at times.

The SCENARIO:
The other week, I went to drive my truck in the morning and discovered that with the engine running, it had very stubborn shifting. It essentially isn't disengaging the clutch fully. The pedal position all fell within spec. No apparently damage to the fork or hydraulics components.

After driving it to my destination and inspecting everything, I had a friend pump the clutch a bunch of times for movement as i was using my phone as a periscope to view the fork. After that, the truck returned to shifting like butter for about a week. I ordered a new Aisin master and slave cylinder anyway.

A few days ago, upon starting it after it sat overnight, it returned to shifting horribly with poor clutch disengagement.

I took it to a shop to have them install the new components, very confident that new parts and fluid would remedy the problem but unfortunately, they say it hasn't. They have quoted me for a new clutch but I am concerned that it may be unnecessary to go to that extent.

I replaced transmission fluid with Redline about 4 months ago and it has remained topped off since then. The shifter bushings were replace about a year ago and Im certain that isn't the issue. It is intermittent partial failure of clutch disengagement .

THOUGHTS:
I spoke with the mechanic about doing a triple check of the bleeding process for the hydraulics on monday morning when they reopen.

Im wondering if even though they appeared fine at first, there may be some fouling of the pedal components under the dash as some minor adjustment has helped other people in some of the other threads I've seen on this topic.

There may be a failure of the fork and/or pivot bolt.

I may in fact need a new clutch and it wouldn't hurt to have one of course but I'm concerned that after the expense, the problem will still exist.

Everyone I've spoken to is befuddled by the on\off again nature of the problem.

Thank you for taking the time to read and ponder this situation. I'm currently traveling on a tight budget and it would be life changing to not have to drop close to $2000 dollars on trying to remedy this problem that seems so close to wanting to remedy its own self.

 

Driveshaft ujoints and center bearing ever replaced?

 

I replaced the rear driveshaft with a good condition used one about a year ago. I grease it religiously.

I'm curious how you think that may be related to a clutch disengagement issue?

 

I think I’m ready to replace my d/s. Depending how its parked if there is a little load on it, it locks up. That’s all.

 

Your confused on your terms pushing the clutch in engages the clutch and allows you to shift .

letting the clutch out disengages the clutch . keeping things from slipping and burning.

At any time was the clutch pedal bracket and the firewall inspected for cracks.

The shop who installed the hydraulics might not have known to inspect that area.

Since this is a intermittent problem and at times works fine I would look real close.

At times things flex enough to not allow full travel of the master cylinder other times they work fine.

Having ruled out the Transmission mount as having failed .

happy hunting.

 

The clutch fork in the bell housing are also known to crack and flex.

 

strange things happen but once they crack seldom do the go back to working in a normal fashion .

 

this is true, just throwing a common issue out there.