Hope everyone had a great Thanksgiving! Been a little while since I have posted, and was hoping I wouldn't have to post problems with the newly swapped trans but oh well. I have just started having issues with going from 1st gear (Not L), to 2nd gear. I will go to downshift from 3rd to second and when I let the clutch out the engine drops to idle and it seems to be in neutral but it feels like it is in gear shifter feel wise. Now sometimes if I don't hit the 1st to 2nd gear just right, it does the same thing; just goes into neutral it seems. If I pull the lever down and right slightly it will go into gear occasionally. The shifter seems to have a lot of slop so I am hoping it is just an adjustment. Fluid levels are fine... Has anybody seen or heard of anything like this?

Just for clarification, I am using the gears L,1,2,3,4,5,6 as opposed to L being 1.

 

No grinding?

Sounds like an adjustment or something loose in the shift lever or fork. Pull it apart from inside the cab and let us know what you see. (Remember we like pics)

 

I sure hope that you can figure out what is causing your troubles. I had my own problems with my ZF6 this past year. Unfortunatly, just about the only way to diagnose what the problem requres someone tearing down the transmission to inspect things down to the molecular level.

My issue was similar in that it was hard to shift between first and second (on the same rail in the transmission). Mine turn out to be a cracked cyncromesh gear.

Good luck.

 

Sounds like something related to the shifting. If it were the syncro's then you'd have hard shifting and grinding trying to get the shifter lever into it's position.

I have my old ZF6 in the garage so I took a few pics for the 'hood to see what is what in the interface between the shifter and transmission.

Looking straight down where the shifter bolts on.

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Close up from the drivers side.

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The business end of the shifter.

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And, uh... we'll just call this one big Jim and the twins.

 

Well I seemingly lucked out in a sense and also not. The roll pin holding the shift selector on was 90% out of it's slot almost ready to drop into the trans and cause major damage. BUT, now, the shift selector is not aligned with the rail which has a large amount of tension to keep the shift lever centered in N, and I have a roll pin which I have no idea where to find, nor do I know how I am going to install it. Any ideas?

 

 

Man that pin has a nasty crack. Get a new pin- are you close to a big city with an industrial supply store? Doubt the dealer would stock this but might.

You might try tying some wire around the piece and the other end around a bar or something. Also maybe vice grips with a T shirt or something to keep from scarring any parts...

 

Why does the mounting flange on your housing look cracked?

Got any big needle nose to push the roll pin back in place?

 

I am hoping the roll pin isn't anything fancy so I can find it locally. The cast looks cracked probably because of the mating surfaces on the shift tower cap which aren't machined all that great.

 

Hey those pictures above, your right and left shift rails don't line in a straight line like mine do. Is that unit in 4th gear? Do your shift rail indentations line up in N?

Thanks guys for the fast replies! I will try to get the roll pin ASAP and use some long needle nose pliers to install the new pin.

 

Yup. It's in 4th for re-install if it ever comes to that since I have a new one on the way. Since that is the direct drive gear it makes it easy to line up the splines- just turn output shaft a little and clutch alignment is much improved.

 

UPDATE:

Well, I have no faith in roll pins or slot pins anymore. After seeing this one cracked, I will definately be shifting very gently from now on. I bet the fracture came from when a tree fell on the donor truck though and probably hit the shifter, but I have no idea.

Here is how I fixed it if anyone notices a change in shift feel. It is such an easy check, I will periodically be popping the cover off to make sure the pin isn't walking out again....


Here is the PN


Here are the two side by side. The fractured one had definately lost its springiness



I rotated the shifter driver sideways and using a magnetic multi tool, drove the pin in far enough so it would hold itself in by friction. I don't have a picture of the pin, but it is just sticking out of the driver. Don't drive the pin in too hard or far, as you will need to line the pin up with the index mark on the center rail seen in the picture.



Then I used some 3/4" drive extensions to hold the shift driver tower so when I pryed on the pin using my spare tire hubcap remover it wouldn't damage anything or pop out of gear.


As the pin was pushed in further and further, I then used a bunch of 3/4" extensions to use the flat side to push the remainder of the pin in. It takes some hammering on the extensions to seat the pin all the way.


The best vantage point is with the assembly in L, or Low gear


For extra security, I noticed that ZF prescribes doing a double pin, so in other words, 'sleeving' the larger pin with a smaller one. Obviously I did not do this.

I noticed immediately the shift pattern, especially L,R,1,2 was less mushy feeling and much more precise which is good. I was really lucky to find the pin almost ready to drop in the trans and chew everything up....




I am curious though Fatdiesel, if you have a chance, could you put the spare trans you have in L, and use a mirror and see if ZF did indeed sleeve the driver roll pin with a smaller one inside? If you don't have time, no big deal!

 

Subscribing for the pictures.
Glad you got if fixed so easily.

 

I'm at work right now but I'll try to do that. Do you know the history of your ZF6? My gut reaction when seeing what was up with yours is someone had a good grip on the shifter when crashing the truck and put a lot of force on it.

 

Yep it has a another pin inside the roll pin.

I'll shoot a pic of my ZF6 when I get it and see what they're doing on the new ones.
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