ZF gears jammed upon reassembly

At first I thought you were kidding. You are an adventurous soul. I'll bet that very few toys survived without disassembly from your childhood. I've rebuilt many of these units and would never of considered that approach. Perhaps a lesser issue is sealing it properly.

Anyway, sounds like the gearshift operating shaft may have disengaged the selector rails.

Adventurous? More like trying to find the easy/cheap way out (I hope)...

I do have the 30-year old Hall ZF tech manual. I studied that a good bit and it appears that the trans and the diff are separate units; during the assembly process the manual has you installing the fully-assembled trans into the fully assembled diff...so I reasoned you could split the two apart in the car.

I had the case separated by about an inch or two, enough to reach in w/ my finger and pic out the broken speedo drive...the bottom half was lying there in plain sight. I then used a punch to knock the top half of the drive, which was still halfway in the drive bushing, down into the pan and plucked that out too. When reassembling, I RTV'd the case halves, which the manual recommends too (the old gasket was of course in pieces). So I hope the sealing issue will be solved (until I pull it back apart, that is).

I think I agree w/ your diagnosis. I pulled the passenger side cover/snap ring/spring off of the gearshift operating shaft. That way I could use a pair of vise-grips to actuate the shaft side-to-side and fore-and-aft to mimic the shifter motion. I was only able to engage reverse. After loosening both hex head slug screws on the pass. side (the ones that are screwed into the shift fork and are accessible from outside, via the small cover), I was able to get some, but not enough, fore-and-aft movement into the forward gears. It's still not enough to positively engage the gears, and when you tighten the slug screws back up you can't engage any forward gears...so you're back to square one.

Before I lift the whole unit out of the car I wonder if there is a way to re-engage that shaft? I doubt it...what do you think?

All I can say is OUCH.

That must have been really hard to do with the trans still in the car. Take it out and disassemble it again. DO NOT FORCE IT BACK TOGETHER. The shift forks must be in neutral when the cases are rejoined or the gears will not engage. Marlin is right if you are not succesful sent it to RBT.

I recommend that you try to repair it before sending it to Lloyd. While it is complicated, if you are thorough in following the manual, you can pull it apart, set it in nuetral and reassemble. The cost will be a new rear cover gasket. Use Yamabond when reassembling the case. If that don't work, you can send it to Lloyd or me if you catch me in a moment of weakness.

JT

JT, Ital - thanks for the advice, I was thinking along those lines. I will let you know how it turns out.

Jack - thanks for the negative commentary, poor spelling and all. I am sure you are a Pantera expert, and your car looks very well sorted-out. You are obviously proud of yourself as you advertise your credentials on this site. Normally I would seek advice from somebody w/ your knowledge, but I have no time for such childish commentary. I am positive that you are many years older and more experienced than I, and it is a real shame to have to read comments like that. I am at least optimistic in that you are the exception to the rule when it comes to the Pantera community, so far this has been a very helpful forum.

Hello CB01, I was thinking along the same lines, nice reply

quote:

Originally posted by MARLIN JACK:
...WoW!! You turn a Non-Operating Speedometer into a NoN Operating TransAxle!!! IF You would have asked US first, We would have told You, DON'T TOUCH IT! What I think is; Get a Bank Loan for $3000.00 and ship the GearBox To RBT! There is NO substitute for Experience! PERIOD! Lesson Learned...

Vise Grips on the Shifter Shaft?? What, Are You Kiddn Me? I Love 'Amateur Hour'!!

This responses from Marlin Jack is a non-sequitur. I tend to ignore them. He does have good inputs when he applies himself and not when he is in his grumpy old man behind a computer mode.

If you get into trouble CB01, you can always call on the experts. Lloyd Butfoy of RBT, Dennis Q of Pantera Performance or some other ZF experts would likely give you really good and accurate advice. Of course, their knowledge is not free. You may have to buy something to get information that will get you out of a jam but will likely steer you on the right course. Our expert advice in this forum is hit or miss, especially on the subject of ZF trans. There are a only a few that would dare attempt a repair on the trans. Fewer still succeed.

Good luck.

Marlin

I think you are letting this get a little out of hand. The ZF is not a mysterious apparatus that could only properly be serviced by Lloyd or Dennis. Most folks with mechanical aptitude and patience could rebuild them following the manual.

I wouldn't characterize someone as stupid who reviewed the manual and felt it safe to crack the case to extract the offending part. Whether motivated by financial savings or the mechanical challenge, for many owners, their passion for the Pantera has been deepened by their succesful tackling of worn out parts on the car. Whether it be replacing suspension bushings, steering rack bushings, wheel bearings, brake seals, master cylinders,an engine rebuild or, the holy grail, the ZF. These repairs/upgrades are often our first experience doing so and they have rewarded us all with a feeling of empowerment after their succesful achievement.

Some people also told me that I was foolish initially disassembling my ZF. I have since rebuilt seven of them for Pantera and GT40 owners. All work beautifully. It is not rocket science,although setting lash and clearances are complicated.

I admire another owner brave enough to crack open the box. Now that he has ventured this far, he ought to be able to pull it apart far enough to line up the shafts and reassemble. That exercise will require no shim adjustment or splitting of the diff case. Easy peasie - my money is that he can do it and have the pride of the highest order Pantera accomplishment - ZF repair. If he should fail, he has options with the vendors and will be no further out financially then had he sent it to them initially.

Many owners derive more joy from working on the Panteras than they do from actually driving them. I suspect that I am among that group as I relish helping others restore their cars. When we ridicule those who step out to challenge themselves mechanically, perhaps we forget our own humble beginnings and how we learned by taking risks.

BTW, I also find it disappointing that people on this list do not use their real names or at least ones consistent with the POCA Forum. A lot more difficult to know who's who.

John Taphorn

Well said, all.

Gentlemen, let's move on.

Once I get through this repair job I'll let you know what I learned, good and bad.

Cory Barack

Hi Cory
Keep up the good work, I am keen to see how you go, (I can't get reverse on my ZF) good luck !

Will it go into reverse if you revove the gated shift plate?

Thanks for the help, but I don't want to high jack this thread, I will start another, (Sorry Cory).

Cory, it occurred to me that a single chip from your broken speedo shaft or something it whacked into inside might have lodged in a synchro sleeve. If so, no matter what manipulations you go thru with the internal/external linkage, such a chip- if it exists- will not be dislodged without disassembly. I hope this guess is wrong.... But I have seen such things happen before. There's just not much spare room inside those boxes!

Good point Boss - I will look closely at the synchros.

FWIW, my speedo shaft broke cleanly in two at the thin part (the machined-down groove where the hold-down bolt rides on the shaft).

Everything went back together w/ no need to replace any parts (exc. the broken speedo driven gear). Unjamming the gears was only a matter of loosening the forks on the rails and fiddling with the linkage until the selector shaft was able to move freely among the 3 shift rails (this took quite a lot of fiddling, BTW). To do this I had to pop a couple of the shift rails out the back of the case. Making sure that it was in neutral before mating it back up to the differential was also important. Now the car has seen its first road miles (under its own power) in 30 or so years. I've been waiting to drive this thing since I was a kid. Thanks to Lloyd in Anaheim for some helpful advice along the way.

As an aside, these cars really fly and are great fun to drive. The "what is that thing?" looks on people's faces as you go by are amusing.

That's a rare failure, CB; mostly, the forked end of the Veglia angle drive (that mates with the little tongue on your gear just above the thin spot) shears. You're lucky: I've seen a loose speedo gear driven into and through the cases like a blunt nail!
An un-fun ZF-thing a friend found: after digging around inside his ZF, the setscrews that hold the shift forks to the internal shift-shafts should be red Lock-tited and peened, as you lose control of shifting if the forks slip. My friend used 'liberal' quantities of Lock-tite on the setscrews, which ran down the shafts, into the guts of the transmission and froze the entire assembly solid! He had much trouble even getting the thing back apart....