Truck is a 86 F250 4x Dont know off hand the exact year of the ZF I want to say its a 95 I would have to check. IT makes a nasty sound at idle but goes away when u rev it to about 1 rpm and goes away when driving or clutch is pushed in. Here is a quick vid I took with my I-phone .

YouTube - Zf5 vibration

The fly wheel is from a 87 F250. I had had the ZF from the 87 in a 86 F350 I have than synchros went out on second and third so I picked up a used PSD ZF from a reputable source and it ended up going in my 86 f250.

The trans shifts awesome and is great untill its idling in neutral. I have done tons of research and have read a million different things. Any input would be appreciated.

 

Near as I can tell from the video, sounds like the flywheel may be starting to crap out. Weak springs, maybe one or more broken spring.

There is so much other background noise that is hard to tell just from the video. If the flywheel is not working right, I suppose you could be getting the gear rollover (slapping noise) that is common when the duel mass clutch is changed to a regular clutch.

 

is it kind of a loud growling noise at low rpms in say 1st gear, goes away around 1k to 1200rpmish?

 

The 87 F250 had a single mass fly wheel so that is what I used and got a clutch kit for a 87 F250. As soon as any load is put on it while driving it goes away.

 

thats y a smf will do that

 

Is the IDI ZF different than the PSD one? With the old 87 zf5 and factory fly wheel it didnt make any noise at all.

I can live with the noise I just dont know if it is damaging or not.

 

From what I have read on the subject, the noise may or may not be an issue when people do the swap. I would think that it would have several factors, some being the age of the transmission, how worn it is, and a big one is the amount and type of fluid that is being used. What did all the research you did say?
From what I have read, engineers say that the noise is damaging to the transmission, otherwise they wouldn't have bothered with the DMF. Real world use dictates its not really an issue.

My guess is the old zf5 didn't have the noise due to differences in wear from the current one, and/or different type/amount of fluid inside. Many people have overfilled ZF5's and said the noise was lessened, or disappeared.

 

It seems that a single mass flywheel will effect each ZF differently. Some have reported that it sounds as if the tranny is full of marbles, and others no effect at all. Over filling the tranny by a couple of quarts of ATF will quieten the gear roll over. You have to remove the shift tower to do this.

 

The reason I mentioned flywheel is because you said you pulled it used out of an 87'. Stock 87' with a zf trans came with a duel mass flywheel. No mention that it was single mass until a later post.

I'd say you have the somewhat normal zf5 trans noise when changing to a single mass flywheel as the others have said.

 

ive come to notice that that noise seems to be kinda commen in the zf5's. we get alot of PSD's in at work with the zf5 tranny and i hear that noise alot. however, im still not convinced that it isnt due to smething warn or some other issue.