My "New" ZF 5 observations

[EMD_DRIVER]

I've driven the thing for the last two days now and all I can say, is WOW! I wasn't expecting such a drastic difference in take-off speed. It still has a grumbling above 60, but the junk yard shaft will be getting a new carrier bearing and U-joint this evening.

I've also noticed that it tends to growl quite a bit, below 1,000RPM's. Doesn't matter what gear it's in. Once above 1,000 the growling stops. There's lots of time at work, where I'm going really slow. Otherwise, I'd probably never notice it.

It also seems to take a little extra effort, to get it into third. On my first test drive, I didn't quite give it enough of a push and ground the gears a bit.

I've also noticed that it doesn't like down shifting, to anything below 3rd. I usually never down shift to first, but second really winds up the synchronizers before it lets it go into gear.

I am so glad I did this swap! It's like having a whole new truck! In my opinion, this is one of the best "Upgrades" that can be done to one of these trucks. Another big thank you, to everyone that helped!

 

[TWeatherford]

Sounds about like mine. Mine's a bit hard to get into 3rd, and doesn't like downshifting below 3rd, doesn't really like downshifting into 3rd come to think of it. I love my manual transmission, wouldn't ever have anything else.

 

[typ4]

Double check your clutch throw. Also these do not like heavy oil, it will cause all kinds of shifting problems. Mine doesnt like to go into second but I know the synchro is bad.

 

[geonc]

Try some synth Merc V ...that is all I have ever run in my ZF's and both have gone 300k + mi.

Do you have a SMF?

 

[EMD_DRIVER]

Double check your clutch throw.

What should it be?

Try some synth Merc V ...that is all I have ever run in my ZF's and both have gone 300k + mi.

Do you have a SMF?

Don't remember the brand, but I put 2 gallons of good quality Merc V in it. I never heard the gear rollover sounded like at the "Full" level, since I over filled it to begin with.

I did put a SMF in it, with the 12" disc.

 

[Shadetreemechanic]

I would think your growl below 1k rpms is a worn input shaft bearing. Mine does the same thing. I ended up replacing a quart of ATF with lucas in mine which helped the growl but made the syncros alittle more finicky. I also have noticed that my shifter will move up forward and back when I alternate with acceleration and then exhaust braking. I think that is because of the input shaft bearing as well.

 

[Agnem]

Sounds like normal behavior to me. Most manuals you cannot get to go into a gear too low for the speed your rolling, regardless of the clutch, so you have to either increase engine speed to spool up the input shaft, or reduce your rolling speed. If you listen close, you will hear the syncro's complain as they whine trying to match up. When you hear this sound, your not ready to go into gear. I've spent a bit of time explaining this to Matthias with his new truck, and my gear shifts and his sound totally different due to the experience issue. You'll catch on and shift like a pro in no time.

 

[tractorman86]

yup sounds normal, dont think of it as shifting as much as matching engine speed to ground speed

 

[Shadetreemechanic]

Is the growl below 1000k normal on these transmissions as well? I just bought a truck with a zf that growls, and my dads powerstroke does as well, but they both sounds like a worn bearings to me.

 

[subway]

Is the growl below 1000k normal on these transmissions as well? I just bought a truck with a zf that growls, and my dads powerstroke does as well, but they both sounds like a worn bearings to me.

yup, its the cylinder pulses transferring through the driveline. gassers dont have the sharp cylinder pulses of a diesel. i have heard the growling on any diesel 5 speed i have driven at a lower speed.