Question: Question for ZF-6 guys

[07keo02]

Does anybody else have a loud clank and slack in their manual transmission. I get this if I get on the throttle and then let off, like there is slack in the transmission. Also, if I'm starting to take off releasing the clutch and then push it back in real fast, metallic clank type backlash. Definitely not the drive shaft. I thought it could have been the transfer, but I just pulled that to install the pump rub kit, bearings and all seemed really good.

 

[duramaxdiesel]

Not a ZF but on my NV4500 I get the same damn thing happening to me. Annoying.

Nick

 

[Kspen90]

It's normal, just the trans, clutch, flywheel, and driveshaft all matching the others speed. When you're on the throttle the engine is turning the trans and driveshaft but when you let off its the other way around.

 

[dirty_max]

mine does it too when going from 0% throttle to mashing it at slower speeds, and it does it pretty bad when I push the clutch back in real quick, especially when backing up and the truck is driving itself pretty much.

 

[07keo02]

Well I can live with it if it's normal, thanks guys. Did you guys see a little more of this with the addition of a solid flywheel? I assume the stock one absorbed some of the shock, either way it's worth it as the stock ones fail pretty often and can't hold power.

 

[dirty_max]

haha yes mine got much worse when i went to the dual disc with the solid flywheel, but my clutch is also pretty aggressive

 

[07keo02]

Is it the ceramic? Southbend told me the dual disc ceramic would feel even smoother than my kevlar single disc. My single disc won't hold in 5th in sixth at about 425 whp. Wish I would have went with the dual disc but still way better than stock.

 

[dirty_max]

no i got the valair, sintered iron disc. yea i bought a clutch without doing the research and got the wrong one pretty much

 

[07keo02]

I bet it holds though.

 

[dirty_max]

haha yes, it holds the power very well, but trying to manuever your way in any type of tight spots, or backing a trailer is a bitch

 

[zf>allison]

i have the south bend dual disk ceramic button clutch it just got broken in, its grabbier than stock but not undrivable, but you do get that grabby shutter if you take more than a second to take off, i like it but it is noisy just a rattle but my two buddys have dodge cummins both with pinned dual disk south bends there very quiet but the dmax clutches are strapped just a noiser design. i don't mind the noise and you can pull a trailer with it, getting it into reverse is hard unless you hit second gear first then it goes right in,

 

[07keo02]

I decided to upgrade to a dual disk. It's sitting in the garage right now, Southbend said they strapped it so hopefully it won't be too loud. My single disk I have now is pretty quiet, but it couldn't hold in 5th and 6th on the hot tunes.

 

[zf>allison]

streetability of it is awesome, im the kind of guy that can deal with clutch rattle and tranny noise through the solid flywheel i kind of think its cool, it cost me 1749 from dieselautopower.com its not on there site and dont forget a slave cylinder to thats like 220.--my bad u bought it already, you will love it, besides its only noisy when disengaged

 

[zf>allison]

btw my buddy had a dodge with a south bend single disc and 4 low was his buddy when manuvering a trailer

 

[07keo02]

Honestly when I put my single in I picked up a slave cylinder from autozone. Usually I avoid cheaper parts but it was 60 bucks with a lifetime warranty and I have had decent reliability out of duralast OEM type parts. It has worked perfect so far. I may just take it in and see if they will swap this one out.

So once the clutch is out and your driving its not really noisy??

 

[Chanzilla]

All this talk makes me wish I had a ZF6!!

 

[Jakej03]

Mine does it when newbies try to drive my truck, they start letting out the clutch freak out cause the rpm drops to about 600 then slam the clutch back in. The truck immediately brings the rpm up too fast causing the clunk, its done this since i bought it, but it is now exaggerated because of my solid hub kennys pulling parts dd clutch with a solid flywheel. So when you see the valet guys speed up.
:driving:

 

[zf>allison]

When the clutch is out its silent but u can hear the tranny internals moving but it isnt that loud

 

[07keo02]

Well I'm glad this banging type noise is normal, my truck has always shifted good and all I just thought it sounded a little abnormal like something was slamming together making a loud banging noise.

 

[07keo02]

Has anyone happened to have used this jack before for their clutch install?

http://www.harborfreight.com/800-lb-low-lift-transmission-jack-69685.html

Back when I did my single disk I had access to the craft shop on base, not sure what I'm going to use to drop the ZF in my garage this time to get my dual disk installed.