Tranny/Clutch issue

[jkl72-40]

Hi all, On my 72 40 its very hard to shift and worse to get it into reverse. I did replace the slave (and clutch is new) but not really any better and no change when the truck gets warm. The motor did get rebuilt so maybe when it was all pulled and put back something was missed any ideas? I do have 1 inch of play in the pedal and it feels normal pressure and bled. Any ideas of what the issue would be?

 

[Skreddy]

Is the rod from the slave cylinder to the clutch fork adjusted properly? Is the throw out bearing riding on the fingers of the clutch all the time or is there a little gap?
Do you still have the 3 finger clutch or the newer, diaphragm style?

 

[charliemeyer007]

Perhaps the clutch master is going bad - not providing enough fluid to slave so it can disconnect the clutch. The slave adjustment rod could be incorrect. Make sure your bolts holding the tranny to bell housing are still tight. How is the fluid level in the tranny/transfer.

 

[jkl72-40]

Is the rod from the slave cylinder to the clutch fork adjusted properly? Is the throw out bearing riding on the fingers of the clutch all the time or is there a little gap?
Do you still have the 3 finger clutch or the newer, diaphragm style?

I believe so... not sure on the T-O bearing Ill have to look Are you wanting a little gap? And not sure if 3 finger or not

 

[Skreddy]

I believe so... not sure on the T-O bearing Ill have to look Are you wanting a little gap? And not sure if 3 finger or not

Yes you want a little gap. If it’s the 3 finger type, the fingers need adjusting as well.

 

[jkl72-40]

Perhaps the clutch master is going bad - not providing enough fluid to slave so it can disconnect the clutch. The slave adjustment rod could be incorrect. Make sure your bolts holding the tranny to bell housing are still tight. How is the fluid level in the tranny/transfer.

How would one know if the master is going? Its not leaking. Ill check the slave adjustment and the tranny bolts.. Fluid is full no leaks

 

[charliemeyer007]

The master can leak internally. Try pumping the pedal several times quickly and see if you can shift into gear better. There are kits for the master - they work well if the bore isn't all pitted/rusted up.

 

[DesertFJ40]

Is it hard to shift into gears even when the vehicle is off? There could be a lot of things, but let's do a checklist and start with the simple things:

Yes, you can easily inspect to see if the throwout bearing is riding on the clutch preasure plate fingers from the side of the bellhousing. Make sure the vehicle is off. You can look on the side opening (if it's still the orginal transmission, the inspection port will be on your passengers side) it looks like a little rectular window..... Using a cell phone with a camera to get in there will be the easiest to see eveything. Or you can just remove the bottom inspection cover of the bellhousing and look as well.

Also, not sure, but was your entire clutch, flywheel, pressure plate replaced? I'm just thinking, but if it did, maybe the throwout bearing got put on backwards. You can check to see at the same time as the step mentioned above.

2nd would be to make sure the fork is adjusted correctly at the slave cylinder. If I remember correctly, there should be 3mm-4mm of play. Then you check the pedal height and pedal freeplay at the master cylinder. That can be adjusted inside the drivers side foot area of your Fj40. There's several forum posts on ih8mud that go through this. A bit confusing at first, but once you get down there and see how it works, you'll understand it.

3rd would be seeing if your master or slave is going bad. But they tend to last a really long time. The original from my Fj40 bit the dust after 40+ years, so I had to replace it at that time. But even then it was still drivable and I didn't have difficulty shifting, it was just leaking fluid. I Doubt yours is bad since you just replaced it.

Next thing I can think of is that maybe the clutch disk got put in backwards. I think you're able to see it through the bottom, but it's really difficult to distinguish, but still possible.

if you're able to shift when the vehicle is off with no issues from 1st-3rd gear (assuming you have a 3 speed) but not when driving, at that point maybe one of your syncro rings is completely worn out and would require for you to replace that part inside your transmission. Or you can just double clutch everytime you shift.

So easiest is just to inspect the throwout bearing and adjust your pedal free play and slave cylinder. Let us know what you find out after that :]

 

[Skreddy]

@DesertFJ40; good point on synchros. If it’s a 3 speed, what gears and what does hard to shift mean? 1st and reverse are non synchro gears in a 3 speed and will be more difficult to shift into when moving.
If the issue persists when stopped and running, it’s likely an adjustment issue or bad slave and/or master cylinder. Most advise to replace the slave and master at the same time.

 

[pb4ugo]

As others have said, 1st and reverse aren't syncronized and can grind going into them. You can bump 2nd or third to stop the trans from spinning with the clutch pushed in, then shift into them. You mention you replaced the master. The pedal height adjustment is critical to get the masters full stroke. Pedal free play is when the slaves' piston starts moving. I depress the pedal by hand and watching the slave for intial movement. Then adjust the rod at the fork. Below is the FSM instructions from a 1974 manual.

 

[jkl72-40]

IDK if this pictures works but did replace the master as well as the slave.. Ive owned this 40 since 2003 had the motor rebuilt and since the rebuild its been much harder then normal to get into 1st and much harder to get into reverse.. LMK what you guys think maybe need a better picture?

 

[jkl72-40]

There is about 3 mm play at the throw out and about 1 inch play at the pedal

 

[pb4ugo]

Did you measure the pedal height. With the replacement of the master cylinder you need to adjust the pedal height, then the pedal free play(1-7mm). Pedal free play is not when you feel resistance, it's when the slave cylinder piston starts to move. It may require someone watching the slave and someone pushing on the pedal with their hand. Be sure the return spring is in place and the piston is pushed back in the cylinder. Once that's set, then you adjust the rod at the fork.

This insures your getting the maximum stroke out of the master cylinder.

 

[jkl72-40]

Did you measure the pedal height. With the replacement of the master cylinder you need to adjust the pedal height, then the pedal free play(1-7mm). Pedal free play is not when you feel resistance, it's when the slave cylinder piston starts to move. It may require someone watching the slave and someone pushing on the pedal with their hand. Be sure the return spring is in place and the piston is pushed back in the cylinder. Once that's set, then you adjust the rod at the fork.

This insures your getting the maximum stroke out of the master cylinder.

Ok will do thank you very much! Hopefully do this evening!
K

 

[Its me shaneus]

The master can leak internally. Try pumping the pedal several times quickly and see if you can shift into gear better. There are kits for the master - they work well if the bore isn't all pitted/rusted up.

Boy howdy! My first 40 had bad habits! If you just lightly touched the clutch pedal it would not flare the piston cup and fluid would leak past the piston. Had to firmly step on it to make it work like it should.

If you screwed up and were too gentle the pressure plate would shove the slave cylinder back in and the leaky master would let it! At that point you were lurching forward into traffic ready or not! Ahh, good times!

On more helpful note: I am on the third engine trans combo in my current 40. Somehow the parts pile left me with too short a rod between slave cylinder and fork. Had to make one using coupling nut and bolt to make a longer and adjustable link. When the too short part was used it didn’t engage clutch enough to allow shifting.

Also, if for some reason your bellhousing bolts get loose, your clutch wont work. Was rather embarrassed to find that had happened to me (also on my first 40). I should have called it christine.

 

[jkl72-40]

Boy howdy! My first 40 had bad habits! If you just lightly touched the clutch pedal it would not flare the piston cup and fluid would leak past the piston. Had to firmly step on it to make it work like it should.

If you screwed up and were too gentle the pressure plate would shove the slave cylinder back in and the leaky master would let it! At that point you were lurching forward into traffic ready or not! Ahh, good times!

On more helpful note: I am on the third engine trans combo in my current 40. Somehow the parts pile left me with too short a rod between slave cylinder and fork. Had to make one using coupling nut and bolt to make a longer and adjustable link. When the too short part was used it didn’t engage clutch enough to allow shifting.

Also, if for some reason your bellhousing bolts get loose, your clutch wont work. Was rather embarrassed to find that had happened to me (also on my first 40). I should have called it christine.

Ill check the bell thanks!

 

[jkl72-40]

No change. Is it possible that when the shifter went back into the tranny something could have bent?

 

[Its me shaneus]

As a last check while inspection cover is off I would jack rear wheels off the ground, put in first gear, and while someone pushes clutch pedal to floor I would try to spin driveshaft, even if pipe wrench is needed. While doing this watch clutch movement and listen to amount of sliding friction clutch disc is making (and how hard driveshaft is to spin).

If driveshaft rotates easy with little clutch noise, then I would start to stare at tranny.

Edit: Obviously make sure you’re safe while doing all this.

 

[Living in the Past]

Not seeing the three fingers in the pressure plate. You do have three fingers pressure plate and not the diaphragm style? Flywheel, pressure plate, throw out bearing clutch fork are matched sets either three fingers or diaphragm. Clutch fork is stamped steel for three fingers style and cast iron for the diaphragm style. Your clutch fork looks like stamped steel.

 

[DesertFJ40]

It looks like a 3 finger clutch pressure plate to me. It's just the fingers themselves are tucked further in and hard to see (at least while taking a picture) . He'd really need to get his phone all the way in there to get a photo of them.

Could be a possibility, you never know and always good to be certain. I also like the idea of the push rod being too short as mentioned above

Here is a shot from the underside of my bell housing when I was swapping things out. As you can notice, kinda of the same angle and the fingers could not be seen.

The I peaked my phone up further and they could now be seen

here is one more once eveything was replaced. Again, my phone had to be tucked up in there to get a photo of the fingers for the cltuch pressure plate.