Hello everyone im new to the site and could really use some information. I own a 1978 f-150 with a 4.9l 300 mated to a np435 with np205 t-case. Just this past week i encountered my first drive train problem ever. I started the truck, depressed the clutch and i cant put it in gear because the clutch is not disengaging. I can shut the truck off, put it in gear, start it, although it kinda wants to lurch forward then let the clutch out and it will take off like normal. However when i try to shift into 2nd, same thing, grinding because of the disengagement problem. My guess is that the clutch fork bent as its old and original? If this is the case, can i remove the fork without dropping the tranny? Any info here would be greatly appropriated.

Thanks,
Jared

 

Do you have the same stiffness to the pedal as before the problemn started? If not, you will probably have to pull the trans and do a clutch job.

 

Yeah same stiffness, its strange because i just used it last weekend and it worked fine, the clutch has always felt perfect. Then i didn't try to use it until yesterday and it was not working. I've never seen a clutch fail while its not in use.

Jared

 

Have you tried adjusting the clutch linkage?

 

Yep i did that yesterday, its not a linkage issue i made sure of the simple stuff first. I have it adjusted within factory specs and i even tried to get a little more throw out of it and still nothing. Is it possible to remove the fork without dropping the transmission?

 

Ok, just had to check. Umm, it's been a while since I messed with a clutch, but I'm fairly certain you'll have to pull the trans.

 

It figures. I was just hoping there was a way to remove the fork without going through the whole business of open heart surgery on my vehicle.

Jared

 

I can't really imagine the fork bending, though.

 

I dont know what else it could be. The clutch still works fine if i start the truck in gear and let it out it takes right off as it should. Something is just preventing it from disengaging. its possible the throw out is stuck because i dont really drive it during the winter months. It just makes me wonder how it worked this weekend fine and then not at all yesterday.

 

when i was younger i had an extremely heavy foot and i had to change clutches more than most people did oil. this was on a 1979 ford f100 300 6 that i drove like it was a ferrari. my problem was the center of the pressure plate would wear down and my throwout bearing would get stuck in the plate until i shut the truck off, then i could freely change to the 3rd gear and drive it home. i dont know why but as soon as i would turn it off i could change the gear. what always seemed to fix it for me was a new clutch, pressure plate and throwout bearing.

 

If friction in a worn clutch is rotating the input more than the worn synchronizers can handle, you have the behavior you describe. Theres a rubber bushing in the clutch arm pivot that wears out and creates quite a bit of slack.

 

I was thinking worn throw out bearing, but I like the idea of the pressure plate being worn also. I know you don't want to, but it would be best to take it apart and see what's going on in there. There's no sense in guessing and throwing parts at. Get in there and get a good look at it and see what's going on and get ALL the problems the first time. You'll be happier in the long run.

 

Check the Z-bar bushings on both the frame and engine side, also look at the bushing where the rod attaches at the top of the Z-bar. If those parts are worn out then all the pedal travel goes for taking out the slack. Check eveything you can before pulling the tranny.....but I will say a clutch can be right at the point of going bad for a while and all of a sudden......it goes out..Good luck with it!

 

Thanks a lot guys I guess I'll be pulling it apart as I checked all external potential problems.
Jared

 

You probably know this but with 4wd it 3 times faster to pull the engine to get to the clutch than it is to pull the t-case and trans.