1994 ZF 5 speed, loud knock, please help diagnose.....

[Still Strokin]

HI guys, went and looked at a truck to buy this past weekend but was hesistant on buying it since all the noise from the transmission,... I know ZF5's are known for noise but this sounded like a rod knocking.. I actually thought it was a rod knocking till i climbed under it and listened to it while running.. The truck is a 94 F350 SRW 4x4 .... Turbo IDI 5 speed.. It has 150,000 on it and it had a new clutch put in 5,000 miles ago from Ford.. I honestly don't know if they put a dual mass flywheel in it or a single... Hell they could have resurfaced it for all i know.... It makes the knocking noise when its idling in neutral , foot off the clutch... It didnt seem to change when pushed in the clutch either.... Now, when I placed it in any gear , clutch fully depressed it went away.... Do you think this is a input shaft bearing going bad? I'm ruling out a throwout or pilot bearing since they were: 1., probably replaced and 2... normally squel.... Do you guys think that input shaft is moving up and down slightly? Again the noise is present whether the clutch is engaged in neutral, partially disengaged or fully disengaged... But the noise completely goes away when the clutch is fully disengaged and the truck is in any gear.. I dont know what it sounds like driving down the road, I didn't get that far in the test drive

 

[gonecrazyi]

Could also be an injector. I've bought trucks that were supposedly about to blow up. Half the time its an injector or a loose flex plate. The other half is a bad flywheel.

 

[Still Strokin]

It definatly needs injectors . It smokes white pretty good at idle and you could see it stumbling a bit.. Noise is definatly coming from front of transmission though....... I dunno, it had a cracked exhaust manifold, oil leak, needed a complete repaint and a new bed & fenders.... Cab is solid though... I thought $4000 was to much.... needs lots of work but is already a dana 60 truck... no conversion needed

 

[riotwarrior]

As odd as it seems....take the front inspection cover off the trans...see if that helps noise...

Sounds like a decent rig for fixer status. 150K is not much, a lil TLC new injectors, return lines, and maybe IP you'ld have a nice ride!

 

[lindstromjd]

$4000 for a truck that needs $1000 worth of work (IP, injectors, flywheel, time)? You can buy a much nicer truck than that for that price.

 

[BigDiesel]

Sounds like the dual mass flywheel is shot. Take the flywheel inspection plate off and grab the pressure plate (in neutral), and see if theres rotational play between it and the ring gear. I believe over 1/2 inch is worn.

 

[RLDSL]

Sounds like the dual mass flywheel is toast. Use the search feature to find out exactly how much play is ok. A single mass flywheel will usually make noise when moving slowly in gear and that's only when the 11" clutch set is used that only has about 5 springs in it's hub, a smf set with a 12 1/4 in set that has about 9 springs in it generally won't make any more noise than the stock setup

 

[RLDSL]

to add, if a couple injectors are pooched, it can mimic a toasted DMF if the flywheel is less than perfect as well

 

[Still Strokin]

to add, if a couple injectors are pooched, it can mimic a toasted DMF if the flywheel is less than perfect as well

I think you are on to something there... I am going to lean towards the DMF if you guys are thinking that is what it is. The injector issue is makin it more noticable... Its a shame because this is the exact truck I've been looking for..... 94 f350 single rear wheel 4x4 5 speed reg cab long bed.. Its black and silver... I was going to do a frame off restoration and repaint it all black... It has the C5 axle code, so that means 4:10 gears... Perfect for installing a set of 33's on it over the skinny 235-85-16's... I just can't justify spending $4000, and we all know that by the time I paint it, put new tires on it, fix the injectors, and fix everything else I haven't even found yet, that it will be an additional 3 to 4k ...... It does have low mileage though, and it runs strong... Hell the guy was using it to haul 10 round bales of hay when I showed up to look at it.