I'm having some minor issues with the tranny/clutch in my truck. The biggest issue is a good deal of shudder/jerk from the truck when getting going from a dead stop. It's worst in the morning when the truck is cold. After a few miles down the road, it'll usually launch with no drama whatsoever. It also seems to want to buck a little when reversing, though this seems to happen REGARDLESS of whether the truck is warm or not. The jerking in forward motion varies from 'not that bad' to 'trying to launch a car with the TC on and failing miserably', sometimes requiring me to clutch in and start all over (usually not much better the 2nd time around).

Now, it could just be the way I'm driving it. The last truck I owned also had a ZF-5, but it was an 89 F250 with a 351W, so I know it was a slightly different flavor. In THAT truck, there was a sticker/label on the backside of the driver's visor explaining that 1st gear was really only needed either with a heavy load or starting up inclines and to otherwise start in 2nd. This truck doesn't have that sticker, but I still use the same technique. I have noticed the truck doesn't seem as eager to take off in 2nd as the last one. Does my truck NOT have the label because you're NOT supposed to start these wider ratio trannies in 2nd? It should be noted that the shuddering/bucking more or less goes away if I start in 1st, so I've begun to do that lately. It works, but just makes for a lot of shifting getting off the line.

I also just finished reading a troubleshooting tech write-up from ZF that states we shouldn't drive at RPMs less than 1k RPM due to potential tranny wear and premature failure. Oops! Gotta stop doing that!

Another piece to the puzzle...... I did have the slave cylinder replaced back in June when it developed a leak. The shudder had always existed before, though (owned the truck since February), but one thing that concerns me is the fit between the new slave and the hydraulic line going into it. It's.......wobbly. Don't now how else to describe it. Loose would imply it would come back out with a yank and/or leaks, neither of which is the case. But the line does have the ability to wobble a bit within the body of the cylinder. I didn't pay that much attention to the original unit, so I have no idea if that is normal or not.

Other than that, the truck shifts fine. The clutch has great engagement (about 2/3 of the way through the stroke) and doesn't slip in the slightest. Clutch fluid level remains constant. Admittedly, I haven't pulled the inspection plate off the bottom of the flywheel to take a quick look, but I don't hear anything clanking around in there.

Mike

 

Have you replaced your dual mass flywheel with a single mass flywheel.

 

Mine would also do that shutter thing when cold only though, and not always, only once in a while, but mine has a tired DMF.

 

It's still original in there, so I would guess DMF. Previous owners used it to tow horses and a boat, so I'm guessing they may not have been too kind to the clutch. Haven't had a chance to put a load behind it yet to see how good the clutch really is, but like I said, it drives fine otherwise. Tried to pay close attention tonight when driving home. 1st masks the issue real well, but it's still there.

Mike

 

sounds to me like you need a SMF. Pull the inspection cover off and see if theres any little parts in it, like springs and stuff. See how much play the flywheel has.

 

When you say 'play', do you mean front to back or being able to spin the flywheel a bit or......?

Mike

 

Your starting in 2nd gear with a diesel ZF-5??? I hardly ever did that....and still wont to this day. Use first gear to start out....it took me a long time to get used to that because I had a T-19 4 spd and I started in 2nd most every time except when pulling.

 

I used to start in 2nd all the time, then realized that it was just contributing to wearing out my clutch lol

 

I mean being able to spin it freely. There shouldnt be any in and out play.

 

I assume I also have the DMF and have no inspection cover on it, so if anything went loose, it already fell out.
I'll be checking all the mounts and fluid when I get a chance, other than that,
When I get enough coin, I'll do a swap to a single, in hoping this will eliminate this.

 

Well, yeah. I mean, right or wrong, you can kinda understand my reasoning to it. I didn't know the diesel ZF5 used different gear ratios up until I read that tech write up from ZF a couple days ago.

Mike

 

Dont feel bad, lots of guys start in 2nd. It wont kill it or anything lol

 

I used to have a ZF in my truck and I started in 1st. No shuddering. I now have a T19 in my truck and start in 2nd. I noticed that granny gear in the T19 is about the same as 1st in the ZF. My T19 will shudder when starting in 2nd. How much are you pushing on the go pedal when you start of? I noticed that it don't shudder as much when the throttle is higher.
PS I have a my old ZF SMF flywheel if you want it to swap out your DMF.

 

Admittedly, I tend to not gas a vehicle more than I have to to get it going so as not to have to slip the clutch as much. I've made deliberate attempts to give it a bit more juice in the past, especially when it acts up. Sometimes it helps, sometimes not.


Thanks! I appreciate the offer, but I think I can milk it for a while right now. And if I have to open it up to replace anything, I'll just replace everything brand new.

I still have to get around to pulling the inspection cover and taking a peak, but that can wait until it isn't so damn scorching out there!

Mike

 

OK man. Hope ya get her fixed.