I have an '87 F250 but it has the older style carbureted driveline, T-19, BW 1356 T-case, D44 TTB, and a Sterling 10.25 semi floater rear so I am posting in this era forum.

I went to leave work last night and as I pulled out onto the road felt a skip, or bump, kind of like I had run over a 2x4.
No gnashing or other knocking, crunching etc..
Not 100 yards down the road it happened again and I had no motive power.
A gearbox full of neutrals.
It didn't seem 'big' enough to be a R&P letting loose.
I coasted to the side trying every gear.
I got out and locked the hubs, put it in 4wd, and then 4Lo, still nothing.
I can feel and hear the transmission moving through the gears.

I would *think* if the clutch or flywheel let loose there would be mayhem inside the bell housing, and that if the T-19's input shaft had snapped it wouldn't move through the gears so easily since it wouldn't be turning.
The gearbox was rebuilt 3 years ago and hasn't shown any signs of failure.

The mainshaft is as thick as my wrist and I have never destroyed one without fragging the case, accompanied by a LOT of bad noise

The 1356 transfer case has always been a little noisy but hasn't ever been opened in almost 350k miles.
I've changed the ATF twice.
Could it have jumped to neutral internally? (I still feel detents)
Could the pump and planetary gears have failed?
(I have a known good spare.)

I'd get out and rip into it but it is raining for the foreseeable future and I have a torn shoulder that needs labrum surgery .

Has this happened to anyone else?
Any ideas or advice are welcome.
I really need to fix this so I can get my tools to work.

 

Could be the center hub of the clutch disc has failed.
I'd think that if it were any further back than the clutch, you'd be hearing lots of unpleasant noises.

 

Would it skip and then catch and take me down the road with no noise, then fail completely?
Maybe I can see through the clutch fork boot if the shaft is turning with the engine running.
Regardless I'll have to open it up.
Thanks for your advice!

 

Try jacking up the rear, lock the trans in gear (2wd) and see if it turns over or not. If you can get help, have someone try to shift it while turning it over. Could also lock in the front and see if it hooks up. I would sooner think it will be a clutch. Had one let go on a little 4 cylinder Mustang, it pretty much just started to revv, no real banging or racket at all. Just a clutch disc...

 

Put the rear end up on blocks (while in 2WD), start it up, put it in gear, look underneath and
see what you can see....

 

The skip-catch-skip-catch cycle before total failure sounds like the center hub and outer friction surface are no longer connected to each other.
This certainly wouldn't be the first time this scenario has happened.

 

I had it in gear with the engine running in both 2 & 4wd with all four wheels on the ground - while underneath it looking for shafts spinning, leaks, listening for sounds.
(yeah, I know, I'm not too bright)

Looks like I'll have to have a mechanic replace the 2 1/2 year old Sachs clutch.
I can't lift my elbow at all, let alone over my head...
To me it is!
I never seem to do anything so low key.

 

Just wanted to say that THIS is the motivation I need to swap in the 60k ZF5 and new(er)) 1356 I have had sitting out back of the barn.

If I need to do the clutch anyway, I may as well bite the bullet and get the correct flywheel/ring gear to accept the 12" clutch I need for the ZF's input splines.
The only other thing I'll need is a fresh tranny mount since I scavenged *everything*
from the donor.

I'd like a longer stick like was shown in one thread on this site, but I can find a crap shifter on Epay and mod it to bolt on later.

Since it will have to be done at the shop I don't know if I'll get pic's for yet ANOTHER swap thread...

 

Well, here it is.

I somehow managed to snap the input shaft.
<a href="http://www.flickr.com/photos/24183730@N03/5199201869/" title="IMG_0387 by Jim_Urrata, on Flickr"><img src="http://farm2.static.flickr.com/1424/5199201869_35ef9aabb4.jpg" width="500" height="375" alt="IMG_0387" /></a>


And,....
<a href="http://www.flickr.com/photos/24183730@N03/5199795944/" title="IMG_0385 by Jim_Urrata, on Flickr"><img src="http://farm5.static.flickr.com/4154/5199795944_4f46211d78.jpg" width="500" height="375" alt="IMG_0385" /></a>

...the input sleeve that the throwout bearing rides on.




Well, I have an extra BW 1356 transfer case, a relatively new 460->T-19 bellhousing and throwout arm, and an entire pedal support assembly with good bushings from the '89 donor truck.



.

 

You see the rust where it's been fractured for a long time?

It looks like it might either have been a flaw in the metal when it was manufactured, and it finally broke lose, or it was fractured and lasted a long time before it finally finished itself off and broke all the way.

I'm leaning toward manufacturing defect though, as the color of the rust matches the surface rust on the rest of the spline and shaft.

 

*gasp*

Interesting.

 

Yeah, "interesting"...

Those T-19's are pretty much bulletproof (except the syncro's)
With a manufacture date of late '86 that poor shaft has held up to a LOT of youthful indiscretion.

The replacement ZF has a thicker input shaft.

I need to edit my sig....

 

Hmmm, didn't see that one coming........

 

was that a all metal throw out bearing? or did it have a plastic hub on the back that went onto the clutch fork?

 

mine has the steel one on them !