My 2000 F350 4x4 has developed a pop in the ZF 6 speed. It only happens when shifting gears, at first i thought it was a u-Joint, or slip yoke but all were ok. The gears dont grind and the clutch it tight, the fluid also looks good. Anyone had this problem before the truck only has 106000 on it but I have used it fairly heavily for towing. Any ideas? thanks

 

forgot to mention its not as noticable in the stock tune, but when i turn it up its definetly noticable.

 

Can't say that mine's ever popped before. Does it buck or jerk when it pops? Can you narrow it down by say just pushing the clutch in and letting it back out without shifting, clutch and shift into neutral and let it out, shift into the next gear but not let the clutch out (just coast) for 50 yards or so, then easing the clutch out?

Popping noises with no grinding has me thinking it may not be the tranny. Front hubs unlocked? Carrier bearing feel ok? Does it happen empty, towing or both?

 

It happens more while empty, its hard to explain but it doesnt pop until I hit the go pedal. Its kind of like theirs play in the gears and when I hit the acelerater after changing gears it will make a loud pop like metal on metal. Then when im up to speed and take my foot off the pedal and then acelerate again it will do the same thing.

 

Does the shift handle jump?
If you rest your hand on the shift handle, do you feel something shifting against it?

 

The other thing you might try is raise the rear axle off the ground, rock the driveshaft back and forth with the tranny in OD.
See if you can narrow it down that way.

 

Cant feel it through the handle, I had to replace the pinion yoke when i first got the truck because the previous owner let a u-joint go to long and it wore the metal out but it felt kind of like this but the yoke is fine as well as the rest of the u-joints. The odd thing to me is it does it in every gear not just od, which made me think its behind the tranny but everything is tight. Im stumpted

 

Check the slip joint, if the splines are dry they could be the cause. Do manuals have the slip joint in the drive shaft?

Dan

 

Seems a little to violent to be that but will check it out.

 

Yes they do, if it is a two piece unit, like mine has.

 

I just had another thought.
My 91 F250 E4OD 4x4 made a similar type noise, but it was coming from the rear axle.
I would be driving along, and a light would change in front of me, forcing a stop.
It would put a deceloration load on the rear axle.
Come up to the light and wait, as soon as it turns green and I go, there would be a very loud pop noise coming from the rear axle.
I'm guessing the spiders were shifting inside the cage.
I removed the rear cover to inspect everything and couldn't really see anything wrong.
but after I drained the old, and I might add, VERY WORN OUT oil, the noise never happened again.
It also gave the added benefit of only having to give half as much throttle to maintain speed on the highway as before.
.
I recommend that you get the rear wheels off the ground, on stands, and start rocking the driveshaft back and forth.
Try it with the parking brake set and the tranny in neutral. You should only get enough movement for the gear lash and axle splines in the rear axle.
Then try it with the brake released and the tranny in gear. You should only get enough movement for the gear lash in the tranny and a tiny little bit of sponginess for the clutch hub.
You should be able to narrow it down that way.
The sloppiest component IMO will be the culprit.

 

just checked pulled the boot down and the splines were nice and greasy, so thats not it any other ideas?

 

had the rear serviced when they replaced the pinion yoke, the ring and everything were in good shape with no metal on magnet. I can definetly tell its coming somewhere under the cab. If not tranny is it possible the transfer case?

 

How about the trans mount? I have seen the rubber crack and the trans lift under a load.

 

Rubber seems ok, Im afraid its time to call my mechanic to tackle this one. Just hope he doesnt want to rebuild the tranny.