[updated:LAST EDITED ON 26-Nov-02 AT 09:29 PM (EST)]I'm good with trucks but have never owned or worked on a transfer case. A friend knocked on my door tonight and asked for help. Seems his rear universal broke loose in his '89 F-150-auto-4x4-302 and he dropped the driveshaft. I drove him over to where the truck was sitting. Why is it an unwritten law that breakdowns always leave your truck in the middle of a busy road? Well, the rear yoke of his driveshaft snapped apart (the universal wasn't damaged!) and the driveshaft fell out (probably banging around under there before it left). We needed to get it out of the road, so I suggested he enguage the front axle to try and move it. He tried pulling the lever to put it into front drive, but the result was a lot of loud....er' I'll say racheting sounds...as if someone were using a very huge socket wrench under the truck. No drive from the front. I told him to put it in regular drive (rear wheels only) and I got under the truck to see if the output shaft was turning. Nope!

It seems to me that something locked up in the transfer case or transmission (he was in two wheel drive at the time), locking everything up, and snapping (in this case) the rear yoke (at the rear differential). Like I said, I'm good at most Ford truck stuff, but I'm a dummy at transfer cases or 4x4's. Does anybody have any ideas, thoughts, whims on this? Thanks, Polkat.

 

Polkat,

Nope, seems you have this one covered. It appears that something in the T-case froze, the rear axle and drive shaft wanted to continue to operate being carried by the weight of the rolling truck. With this, the weakist component is going to break. I am surprised that it did not just drag the rear tires and bring the truck to a stop, second guess would be a U-joint failure.

Unfortunatly it sounds like T-case overhaul time.

Lee

 

Polkat,

Oops, I forgot to mention that this could also be a Tranny problem. I am not familiar with this model, is the tranny/T-case one unit?

Lee

 

[updated:LAST EDITED ON 28-Nov-02 AT 10:25 AM (EST)]polkat, yo,
That "... racheting sounds...as if someone were using a very huge socket wrench under the truck. No drive from the front..."
My guess (and simplest guess) is that is the front hub(s) are shot. That type of sound up front is usually worn-out/frozen front locking hubs, esp if they are the auto. locking hubs. Listen to them when he tries to shift into 4H again; you can use a short piece of garden hose or the gift wrap cardboard tube to track down that ratcheting sound. Or do the front driveshaft/axle ck.


Yep, always the busy highways or deserted trails! We lost both hubs on a deserted fishing beach when our Bronco had only 30k miles; ven though they were serviced every 10k miles.
..
as for the yoke
;
We lost the yoke on our 78 Big Bronco too once. Junkyards have plenty of em.

look here for yoke failure diagnosis help (is that truck lifted?):
http://www.drivetrain.com/driveline_...eshooting.html
and as the prev poster suggests; a u joint failure is possible..

Be well!

 

Thanks guys! He hauled it to thje shop and apparently a shaft broke in the transfer case, locking up some gears. If I find out more I'll post it here. I too would have thought the rear wheels would have just dragged the truck to a stop, but apparently the holes in the were already worn thin and it let go instead. Thanks, Polkat