another ZF5 roll over thread.... with excessive roll over noise.

[IDIoit]

i have been battling this for a month or so...

7.3 IDIT rebuilt and runs great.
at first i used a 460 ZF5, and it was so bad that i felt like the trans was going to come apart.
the noise happens with the clutch compressed or not

i ve changed driveshafts, changed transfer cases, and also switched to a kevlar input shaft bushing.

still no change.

i had the thought that i may have drilled the 460 trans incorrectly, so i bought another 460 ZF.
same issue.

so i decided to get a remaned diesel S42 ZF.

got it in lastnight, and its horrible!

im running 5 quarts of Valvoline syncromesh

ive tried mercon V equivalent and penzoil syncromesh.

i dont get it...

the ZF in my 87 is perfect....

what am i missing here?

 

[The_Josh_Bear]

The only thing I can say from experience is that raising the idle makes a huge difference. Maybe the idle is appreciably lower on this rig than your 87?

I don't like rollover noise so my truck idles at about 800/850 rpm all the day long with zero rollover noise.
But drop it into 650-750rpm and it's enough to drive me crazy!

 

[Black dawg]

does it do it with the clutch in and transmission in gear?

 

[gandalf]

Take the ZF out of the '87 and install it. If it is quiet, then your problem is the 460 transmissions you've put in. If it's noisy then you know the problem lies elsewhere, somewhere other than the ZF. Try to duplicate conditions as much as possible other than using the known-good ZF.

 

[IDIoit]

mostly does it when i let off the fuel.
in gear, clutch engaged.
rpm is at 750 on both trucks.

the one i just installed is a diesel ZF.

just talked to my buddy that owns a trans shop, and he told me to pull it apart and shim the countershaft, when the helicoil gears move, this causes the noise.

think i should do a clutch first...
what say you?

 

[Diesilee]

Gees........if the clutch is out so's the tranny, do 'em both!

 

[Black dawg]

mostly does it when i let off the fuel.
in gear, clutch engaged.
rpm is at 750 on both trucks.

the one i just installed is a diesel ZF.

just talked to my buddy that owns a trans shop, and he told me to pull it apart and shim the countershaft, when the helicoil gears move, this causes the noise.

think i should do a clutch first...
what say you?

If it makes the noise with trans in gear, and clutch pushed in....without the truck moving, nothing in the transmission is turning.

 

[IDIoit]

btw, clutch is new. ive got maybe 100 miles on this truck since we got it running.

ive changed everything else tho

 

[franklin2]

Like was said, if you sit there idling with it in neutral and not pressing the clutch, the noise is probably terrible. Don't do anything but put your foot on the throttle and gently raise the engine rpm. Most of the noise should go away.

If it's still really noisey, it may be something with the engine. All the aluminum transmission does is amplify the engine noise like a speaker. There is nothing wrong with the transmission, that is apparent since you have had 3 of them in there and they all do the same thing. The 460's fire smooth since they are a gas engine, the diesel fires hard since it's a compression engine. So all that noise comes through to the trans. Your engine tune may be making more noise than the usual idi?

 

[ROCK HARVEY]

Is your transmission buddy telling you to add internal shims to the transmission to change the bearing preload? That seems like a risky solution to me. I agree with others that the problem might be outside your transmission. Are you sure you didn’t accidentally install the clutch backwards? The rivets/bolt heads on the pressure plate could be eating themselves against the flywheel bolts.

 

[ROCK HARVEY]

Do you still have the inspection cover on your zf5? They tend to interfere with the SMF conversion so maybe it’s rubbing your flywheel? Longshot suggestion I know but I’m just throwing out anything I can think of. This must be super frustrating.

 

[IDIoit]

the roll over does not occur until im driving above 30 mph.

it does have a SMF and im positive its installed correctly.

 

[IDIoit]

just put a new clutch in, and its better, but still i feel somethings amiss

heres a video.

https://youtu.be/jVvtTcF6NOA

 

[Big Bart]

Hard to confirm from the video, but appears you were driving. (VS reving the engine.)

It happens in the video during deceleration.

That sounds like bearings or gears inside the transmission, not your clutch or crank. (But maybe they are part and parcel to the issue.)

Did you alter the flywheel or drill it for the conversion? I ask as perhaps the pressure plate is not centered.

Does it have a new input shaft bushing/bearing in the flywheel or crank? My line of thought is if the input shaft is loose and can wobble, perhaps when the pressure plate grabs the clutch it is not centered in the pressure plate. Thus input shaft is swinging around vs spinning true. Thus creating vibration and noise in the tranny.

Your an experienced mechanic, guessing you did it right, so just tossing out ideas before you tear the tranny apart.

 

[IDIoit]

the clutch is bran new from Napa. it bolted right up.
i ditched the needle pilot bearing and installed a kevlar bushing
the transmission, was just re manufactured.
not to mention the other 2 transmissions did the same exact thing.

im going through the process of elimination, and its kicking me in the 10.25