Question on ZF-5 durability
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Joined: Jan 2001
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From: Connecticut
Question on ZF-5 durability
I have a ZF-5 in my 351 4x4, Shifts great, even stays in reverse, new clutch. This was a boneyard-running truck find.
The only issue is loud "chatter" at a high-way speed only when there is no "load" on the drive train.
If I lay off the gas at highway speeds, and before the truck starts to slow You can hear lots of "gear slapping"
Very quiet accelerating, (it has a load) and very quiet decelerating (under a load). Just in that sweet spot does the gears slap around.
Is this a warning sign of impending doom? or could this be this way for years?
Thanks
The only issue is loud "chatter" at a high-way speed only when there is no "load" on the drive train.
If I lay off the gas at highway speeds, and before the truck starts to slow You can hear lots of "gear slapping"
Very quiet accelerating, (it has a load) and very quiet decelerating (under a load). Just in that sweet spot does the gears slap around.
Is this a warning sign of impending doom? or could this be this way for years?
Thanks
Moderator
Joined: Jan 2001
Posts: 56,984
Likes: 2,738
From: Virginia
The zf trans is noted for transmitting driveline sounds. Ford used a special dual mass flywheel when they put this trans behind the diesels, it makes a terrible clatter and it sounds like there is gravel in the trans when idling behind a diesel engine without a dual mass flywheel. The gas engines did not need this special flywheel since they are a smoother running engine.
So if you are getting lot of noise from the trans, it may not be the trans, it my be amplifying something else wrong somewhere else in the driveline. You will find it eventually
So if you are getting lot of noise from the trans, it may not be the trans, it my be amplifying something else wrong somewhere else in the driveline. You will find it eventually
Moderator
Joined: Jan 2001
Posts: 56,984
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From: Virginia
I saw that in your first post. But besides some gear ratio differences, they are all the same except for the bellhousing patterns. That is why I am suspicous that it might be transmitting a problem from somewhere else. One thing you can do is experiment with it in different gears and see if the noise changes. When you are in 5th, power is being transmitted from the front of the trans, down through the countershaft, up through 5th gear, and out the trans. When you are in 4th, power comes in the front, goes straight through and out the trans, it's 1 to 1. So if the noise goes away in 4th, that is a clue there may be a problem in the countershaft assembly.
Cargo Master
Joined: Oct 2005
Posts: 2,298
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From: NJ
Could be worn out needle bearings on a particular gear if not in all gears. Could be worn input/output or pocket bearings on the mainshaft or countershaft bearings as well resulting in endplay in the shafts (these should be prelaoded a few thousandths.
One of my ZFs the shifter rattles under load in 4th, it has been this way for many miles and could be as simple as sloppy shifter bushings or other worn shifter components or could be a mainshaft preload issue, but I think it would have gotten worse or self destructed by now if the shaft was all spaghetti like.
One of my ZFs the shifter rattles under load in 4th, it has been this way for many miles and could be as simple as sloppy shifter bushings or other worn shifter components or could be a mainshaft preload issue, but I think it would have gotten worse or self destructed by now if the shaft was all spaghetti like.
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