Hi,

I've been doing some reading up, and trying to figure out how to tackle this noise. basically, at idle, and especially from the passenger side, you can here what sounds like an off, and on grind.

The truck was stuck on high idle, and I fixed that, and have it idling around 700rpm(before around 1000rpm); I don't know whether the increased engine noise covered over the grind, or perhaps at higher rpm's the grind goes away, but I didn't hear it until now.

Does anyone have any suggestions on where to start on this?

Thanks in Advance,

Joe

 

Gear rollover noise? Does your rig have an single mass flywheel?

 

^^^ That's why it had the high idle. Increasing the idle is the quick and dirty way to hide rollover.

 

I just read about 'gear rollover noise', but have also read where people say that when a DMF goes bad it'll sound like 'change in a tin can'... isn't that grinding also, or are they talking about a continuous grind?

Are the two sounds entirely different, and unique?

Also, from there, can I determine whether a SMF, or DMF by removing the inspection plate? I've never looked up what a DMF looks like.

If it's gear roll over noise, is that bad, or just a common noise for the zf5?

Let's say it's a DMF, what actually happens with them? I assume it's two pieces(?), do they grenade apart, and ruin bell housings, or?


Will a DMF noise go away at higher rpm as well? Also, in your opinion is the gear noise just part of the zf5?

I ask as I've got an old M-37 with straight cut gears, and that thing sounds horrible when not loaded.

Thanks in Advance,

Joe

 

Gear rollover noise with a SMF is normal. Never heard a DMF go **** up so i cant say for sure, but yes when they go it isnt pretty. you should be able to tell through the inspection cover if you know what to look for, unfortunately, i do not.

 

....From University of Youtube, a couple decent videos; one discusses benefits, and cons of both SMF, and DMF.

The other one is a dissection of a Ford DMF.

I also listened to another video that had the audio of a supposed bad DMF, I guess it should be a continual rattle.

Tomorrow I pull the inspection plate to see whether the flywheel is two pieces sandwiched together, or a single piece.

So far I'm getting the idea that the grind is the gear rollover.... Sounds damn horrible, but so far, from what I read, that's just what a zf5 does; sound bad?!

 

Does the noise go away when you touch the clutch, press it in slightly?
It might just be a worn throwout lever(I forget the correct name of it right now; it connects the slave cyl to the throwout bearing).

 

a DMF can go bad in different ways. the springs can let loose and it will sound like change in a coffee can. or the center disc can fail and it will feel like the clutch is slipping when it gets hot and power is put to it.

mine was a failed center disc in the flywheel. i had a centerforce ceramic button clutch disc in mine after the original disc failed at around 170k miles.
when the DMF failed at 375k, i could put it in 5th and let the clutch out at a standstill and the truck would not move.
let it sit for 6 hours and it would smoke the tires in first, second, and third.
then after 1/2 hour of running it would start slipping again in higher gears.
then the t-case exploded for a second time and i decide to put an automatic in it.
when i pulled it apart, the clutch disc was in perfect shape, but the
fell completely apart when i dropped it on the floor. front half, rear half, and all the springs scattered all over the place.

 

Yep, when you pull the inspection cover you'll know right off what you have, if you see springs in the flywheel it's DM, if the flywheel is solid, it's single.

A while back, (okay a couple of years ), a member @ OB had switched his DMF for a single. He posted a video of the rollover noise and it was horrible. So much so he was considering going back to the DMF and considering the noise I couldn't blame him.

He tried the remedies, over-filling the transmission, different fluids, etc, nothing helped. He ended up installing a different brand SMF kit and the noise was gone. Looks like the first kit was so poorly made it was out of balance.

 

seeing as you are in Arizona, you probably can get away with running gear oil in the trans instead of ATF. that is supposed to greatly reduce gear rollover noise.
using gear oil in colder climates make for hard shifts when cold, but hotter climates should have no problem with that.

 

No, tried playing with that. From inside the cab, it's fairly quiet; the passenger side standing next to the truck, for whatever reason it's very noticeable, and sounds like some bad sporadic grinding...

To try to put it into words, it would sound/read like this: Normal-rough grind-Normal-rough grind-Normal-Normal-rough grind.... and so forth, there's definite pauses in the grind, but not at entirely even intervals.

When I cannot hear it is when actually in gear driving, or with a little increased rpm at idle. I've got the idle down to around 700rpm due to needing to rebuild peddle assembly, and needing to also do the retrofit to the actual master cylinder push arm...just haven't had time, and it goes into gear much easier with the lower rpm.


I get solid clutch engagement, due to the peddle assembly needing to be rebuilt, The clutch peddle has too much slop to properly disengage the clutch, but not bad enough to stop driving(not grinding into gear at all). The truck is harder to get in gear once heated up though, but only 1st, or 2nd depending on which one I start in, but still fairly easy, and without issue.


I pulled two bolts from the inspection plate, it was loose, but couldn't get it completely out, is there a trick to it, or what's the plate regularly hang up on? I could pull it down far enough to see the flywheel, it's a DMF, and from the video above, when worn out, it should be able to be wiggled, but in my case, was as far as I could tell, totally tight.

I'm usually in snow country, so no go. I did check the fluid, and it's topped off atf that looks clean.


************************************************** *******
I'm leaning towards thinking this is 'gear rollover', and haven't read too much on that, is this something I should be concerned about, or is it normal for a zf5? Is there something I'm missing, or other common issues with these transmissions other than the flywheel, and gear rollover?

 

Synthetic 50wt is another option, but will make for harder shifts. Its said overfilling .5-1qt helps alot. Have an SMF in mine and the noise is barely noticable. That said, buddy with a 12v in his 90 F350 has some pretty bad rollover noise, which is saying something because that thing clatters and rattles something terrible.

 

I'm leaning towards 50wt atf synthetic, I know TJC mentioned gear oil, and after doing a lot of reading, the 50wt atf is equivalent to 90wt gear oil from what I've read.

In researching it on the web, I've read a few things that seem consistent: no dino oils at all, 30wt motor oil without any detergents, and of course overfilling.

I think I'm going to hunt down some 50wt atf syn. and see how it goes. I read one guy who seemed fairly well schooled on the subject, and he said the 50wt ATF syn, will work fairly well even at cold temps., better than the 30wt motor oil with no detergents.

Also, what I found interesting was the amount of differing opinions on what to fill, and how much; seems it varies with differing climates, and then there's the old standard of, 'it's a truck, it makes noise, deal with it'.

Thanks for the replies ; my main concern was missing something/anything that could spell catastrophe.

 

If it's a DMF it's not rollover you're hearing. No point in playing with fluids.