So I've got a 92 f150 4.9l 5 speed. I've had it about 2 years now and never had any major problems with the clutch. Some times it will grind a little into first or reverse. Past month it's grinding more often to were it's alarming. But anyway a week ago went to start it and no shift. Popped the cap on the master cylinder no fluid. Added fluid and worked fine. I was under the impression my slave was probably going out due to the grinding previously. Pedal never lost pressure through any of this mind you.

I decided to order everything from the rear main seal to the slave. And Friday afternoon I dropped the tranny the first time. I believe it's the m5od but I don't know how to tell for sure. Everything came apart easy enough. I cleaned everything up as best I could with brake cleaner. Flywheel to pressure plate went in no problems but I realized here that I accidentally got an 11in clutch kit and mine came with the 10. Not a problem had to go pick up some new bolts to fit the 11in clutch but it all worked out fine.

Now the slave cylinder I got was a duralast hydraulic slave, I wanted luk but beggars can't be choosers I work a lot and had a 3 day weekend so needed to finish it now not later. the release bearing on the old slave was 100% busted and who ever installed it put some kind of gasket maker on the underside for some reason but nothing I've read mentioned it being needed so don't know what that's about. But I set the old and new slaves side by side and they were the same height and width. Bases were also the same heights but when I installed the new one it had play unlike the old one. I added some small washers to take the play out. Throw it all back together and bolt it all up. Refilled all fluids and bled the clutch but could never build pressure. Thought the slave was busted out the box (read a lot of those horror stories) dropped the tranny pulled the slave and tried bench bleeding. Learned my master was sucking air. Replaced it. Bench bled them again. Hooked the master back up and very unfortunately clutch got pressed and popped the slave apart. Poured fluid out. We popped it back together and re bled a little. Wasn't leaking or anything so figured it might be okay (didn't have the money to buy a new one lmao and can't find the receipt yet to take it back).

We reinstalled everything and bolted it all up. Clutch had no pressure. We bled the ever loving **** out of it with a mightyvac and the line held pressure so I'm almost positive there's no leaks. Clutch pedal is stiff but when the truck is running the pedal loosens up a bit and no clutch engagement. Ive bled it again and again. The slave is moving when I press the clutch but still not able to shift into anything. And yes I can shift when the truck is off. Gear oil leaked out when I had to drop the tranny the second time, a little more than half a quart id wager, and Im unsure if that's enough to keep it from shifting but I'm out of ideas lmao any help would make my life so much easier. I've got a mechanic looking at it later in the week but if I can avoid spending the money and fix it myself I'd much rather. Ive done all maintenance myself on this truck and id love to keep it that way.
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OK so your clutch is not DIS-engaging. It is engaging so well it is staying engaged full time. Do I have that right?

Unless somebody has changed the trans, you have an M5R2. The only other option would be the ZF5 but that has a granny low gear.

 

Ah yeah that makes more sense. Pressing the clutch pedal does not disengage the clutch.

As far as the tranny model goes. Dude I couldn't tell you lol I'm just going off other things I've read on the forums

 

Can you pump the clutch pedal repeatedly and then build enough pressure to get it to disengage?

 

Negative. I've tried that with no success.

 

Hopefully this helps at all. It's the only markings on the trans other than marker stating 10-23-15



I'm assuming it either got rebuilt or was pulled and put in.

 

Why? Was there something in the instructions telling you to do this?

 

Well no there was no instructions telling me to do that but the amount of play was not ideal in my un professional opinion lmao. Honestly I figured the slaves gunna be forced all the way back anyway and no one anywhere has mentioned allowing play in the slave cylinder that I had read.

 

I have no idea about any of this manual trans stuff. But that Duralast, won’t last long IMO everything of that brand I installed has broken. I’ve taken stuff to AutoZone before with no receipt and they gave me store credit, and wouldn’t give me cash without a receipt. But I wouldn’t say it’s worth pulling a tranny to return it, if that’s needed. Again, I have no idea what I’m talking about when it comes to manual trannys.

 

In my semi-professional opinion, that is where the problem lies. It is a hydraulic system so when the pedal was pushed it would have self adjusted and taken out the “excessive” play that you thought it had. Now the slave cylinder is too close to the pressure plate so the clutch isn’t fully releasing.

 

Im not arguing with you. That very well might be the issue, but you have to compress the slave to get the tranny back on. I still don't see why keeping it locked in place would hurt anything. It's the same distance it would be if I didn't add them. No?

 

You had to do what? That’s not right. No. You have jammed the slave cylinder against the pressure plate. Now it cannot release. When replacing brake pads, you wouldn’t put shims between the piston and the brake pad to take out the free play. It does that automatically the first time you push the brake pedal and then the seal pulls it back a hair to allow it to release.

 

Sorry you're misunderstanding me. I'm not shimming the slave out. I put washers on top to take the slack out of the bolts, eliminating the play. Not underneath to shim the slave out.

 

Ah. Yep, that is not what I thought you were saying. In any case you shouldn’t have had to do that either. Last year, I swapped out the slave cylinder on my transmission while doing the frame swap. Removed the old one and installed the new one. Bolted right in with no modifications needed. It either was made wrong or they gave you the wrong slave cylinder.

 

So you think I should just bite the bullet and replace the slave?

I've got a nagging feeling that the trans is a replacement and might not be the exact trans that came out. The old slave was practically glued into the bell housing with gasket maker.