So I've got a brand new rebuilt, reman, whatever you wanna call it zf5 behind my 347, and i'm not sure I like the way it sounds in neutral. Its clunky, almost like a cardboard box filled with marbles. As soon as you push the clutch it goes away, and in gear I can't seem to hear anything either. What spins in the trans when in neutral that would stop when the clutch pedal is pressed? Could it potentially be something on the motor end of it? I don't remember it doing this with the c6, I wish I had started it up last time the trans was out to eliminate or confirm the engine from this equation. Thanks guys!

 

I think the throwout bearing pushes the input shaft to the rear and that takes lash out. The clearance front/rear on that shaft allows the shaft to move front/rear as the helical gears roll over each other, and that's what you are hearing. I think I've heard it called roll-over noise.

 

I wonder how much of a pain the supplier is going to be when it comes to determining if its excessive or not. They were misleading the first time around, so I don't expect it to be easy. I'll do some research on this roll-over noise though and see if its something that is easily remedied. As always Gary, I appreciate your knowledge.

Hey, just reading your Sig, I bet your dads truck scoots with that stroker in it!

 

Haven't gotten it back together yet. But, the "stoker" put out 500 ft-lbs on Tim Meyer's dyno.

I'd planned on going with the ZF5 I've had rebuilt stem-to-stern, but Big Blue needs that tranny so I'm going with an E4OD. Expecting it'll chirp the tires pretty easily

 

Nope. ZF5 uses tapered roller bearings front and rear, just wheel bearings. Preload is something like .001"-.004". The mainshaft and countershaft do not move fore/aft in the case. If they do, it's because you're grossly over the meager 420 ft/lbs torque rating and the case has flexed. This typically results in a cracked case. Been there done that, several times. I was replacing ZF5s annually from case failure and recently rebuilt one for my diesel using a wide ratio 460 gearset.

The noise is from the lash between the gears of the main and counter shafts. It shouldn't hurt anything according to ZF but it's somewhere between disconcerting and annoying. The noise is exacerbated by an engine that doesn't idle smooth either from being out of tune or a rough idling cam.

The noise can be mitigated a few ways:
Overfill the trans. I run 4 quarts in my ZF5's, fill through the shift tower. Some run more, I'm considering trying 5 quarts on my diesel with single mass flywheel as it does sound a bit like a box of rocks but not as bad as some I've heard.
Turn the idle RPM higher
Use the new design shift boot. This is actually a double boot and is a PITA to install. There is a thick white inner boot and the normal black outer boot. This shift boot really makes a big difference as comapred to the early traditional type of boot.
Install sound deadening on the floor pan (peel & seal is cheap and effective)

 

thats a ton of torque. I'm looking for a dyno here in Dallas to put mine on to do a little tuning. With the locker and 35's I don't really get much chirp, but that front end sure does lift hard from a stand still.

 

I sit corrected. And, I'm glad to know what is really going on. So, the fact that it quits when you push in the clutch just means the input shaft stopped spinning. Hmmm. Good to know.

 

I was just reading up that some people are running an extra quart in there, and I need to find a new seal for that shift tower anways so I might as well give it a shot. i've got 5-6 quarts of Amsoil ATF sitting on the shelf I might as well put to use. Right now my idle is at 750, and thats the lowest RPM the motor seems happy, but I do have a bit of a cam so thats not helping I guess. This new designed shift boot you mentioned, is that soley for the sound deadening attributes that you mention it?

 

Very common on ZF transmissions. I've heard some in diesels with single mass flywheel conversions that absolutely roared in neutral with the clutch engaged. Mine has a slight noise to it but I've grown used to it.

 

I just did the new boot design on my ZF and YES! it does quiet it down, and YES it was a PITA to install. (Gary I gave you the p/n for the new style boot)
But if your idle is low, 500 - 700 rpm it can sound horrible outside of the truck, (rod knock sound) But I love the OD of it.
Annoying at idle, yes, quiet while running and great on gas? Yes, worth it.....

 

Ron - I do plan to get one of those boots and put it on Big Blue when I swap.

 

Now to get rid of the PITA GM style HEI one wire dizzy, Took out the truck today and it's breaking up under a load again, I can watch the tac drop and recover, bucking.
I have the new rebuilt dizzy (thanks Gary on the source for it) found 2 NOS Duraspark 2 modules, New cap and rotor, four "oil can coils" and a Duraspark harness to replace my frayed/broken original...now it just find the time for the swap.

 

EOD or AOD? EOD needs the com-putter.. AOD uses TV.

 

Reamer, do you still have that part number? what about the install was such a pain? The overdrive was necessity for me, as on the highway with 35's im still sitting at 3000 rpm

 

The AOD wasn't even used behind the 351W, much less the 460. So it didn't come in a version that will bolt up. Yes, the E4OD requires a 'puter, so I'll probably go with a Baumann.

As for R's, Big Blue was turning 2750 or so yesterday at a true 70 MPH. No way a 460 needs to turn that fast to pull that truck, so I really want the OD as well.