[DeTomaso] Cruise control again--you how one project causes something else to break...?

[Christopher Kimball]

Dear Mike,

This evening I managed to remove the angle drive unit from the ZF, and as I did a small piece of metal fell out.  I looked closely at the piece and the inner portion of the angle drive.  The good news is the "blade" protruding from the ZF is in good shape.  What I saw in the inner portion of the angle drive was a circle with a line across it.  The areas of the circle on either side were where the tabs extended upward, forming the slot part of the arrangement.

The piece of metal that fell out was one of those tabs which had broken off.  Without both tabs, what you have is not a slot, but more like half a slot, I guess.  Enough to engage with the blade sufficiently to turn the speedometer cable, but not for long!

The fact that one piece of metal was all that was in there leads me to believe the other piece broke off some time ago, and the previous owner just stuck it all back together hoping it would work long enough to make it to the next owner's garage (which, of course, it did).  That also probably explains why the angle drive was flopping around on the ZF instead of being tight--whoever put it back together may have been either 1) rushed, or 2) incompetent.

I talked with a guy who has a bunch of Pantera Parts and he said he has an angle drive he'll sell me, although he hasn't given me a price yet.

If anyone has one they'd like to sell, let me know the cost; maybe I'll be able to snag one for less than a vendor's price.

Thanks,

Chris

From: MikeLDrew at aol.com
Date: Sun, 13 Sep 2009 23:42:35 -0400
Subject: Re: [DeTomaso] Cruise control again--you how one project causes something else to break...?
To: chrisvkimball at msn.com; detomaso at realbig.com



In a message dated 9/13/09 19 55 30, chrisvkimball at msn.com writes:





Before I start trying to strong arm the turnbuckle nut to move, is there anyone out there who can give me some help and advice on what I'm looking at to get the ZF device to work?  I was also told that if I do the wrong thing, a piece (maybe an inner nut) might fall into the ZF which wouldn't be good.





I just went through this exercise on Markus Woehler's car a few weeks ago.



The ZF angle drive is not supposed to be loose on the gearbox.   There is a threaded pipe that exits the case at a 45-degree angle; the speedometer gear passes through this pipe.   The angle drive is threaded onto the pipe.   The end of the speedo gear is shaped like a flat-blade screwdriver and engages a slot in the angle drive.   Bevel gears rotate the motion 90 degrees, ending in a square-shaped protrusion that the speedometer cable engages.



You should not be able to rotate this protrusion by hand, given that it's directly geared to the speedometer gear.   In your case, something is wrong.



The good news is it shouldn't cost too much to repair it.   It is probably just a bad angle drive and Dennis Quella (along with some of the other vendors) have good new and used ones available.   Dennis said a new one is $176 and used is $100-120.   



The other potential problem is that you could have broken the gear that emerges from the transmission and turns the angle drive.   That would be a bit more challenging.   



Here's a photo of the part:



http://www.panterapartsusa.com/cgi-bin/detail.cgi?prod_id=07801b



The geared end goes into the transmission, the other end has what looks like a flat-blade screwdriver.   That engages the angle drive and turns it.   What could have happened is that the screwdriver blade broke off.   If that's the case, then you have to do some gearbox surgery.



Look at this drawing:



http://www.panterasbywilkinson.com/webpages/catalog/ill11a.html



You can see that the gear (part number 801) enters the transmission at a 45-degree angle, and is retained by a 17mm bolt that rides at a 90-degree angle to it (part 804).  If the end of your gear is broken, what you have to do is remove the bolt while retaining the gear with a pair of needlenose vice grips or whatever, and then carefully withdraw the gear from the transmission.   It has an O-ring that seals it against the inside of the sleeve to keep it from leaking oil, but if you goon it up, clink clank you'll drop the gear down inside the transmission.   Then you'd have to fish it out with a magnet which would be a major problem!   In the worst case, you'd have to take the gearbox out, and remove the bottom cover to extract it.



You can see from the first link that this gear is a pretty spendy part, so I hope you haven't broken it.   However, if you have, the good news is that I've got a brand new replacement gear in my NOS parts stash, still in its original Ford box, and I'll make you a better deal than the vendors ever would. :>)



You may have difficulty getting the angle drive off.   The nut threads onto the sleeve on the gearbox with a regular RH thread and is threaded onto the angle drive with LH thread.   Hopefully you can turn the nut and back the angle drive off.



Once it's in your hand, it's easy to test--just insert a screwdriver into the gearbox end, where there's a slot, and turn it.   If there's no corresponding turnage on the output side, then you have found the problem.   On the other hand, if it works, then look carefully at the end of the drive gear and you'll probably find a broken-off screwdriver end.



So, do the troubleshooting by removing the angle drive, and then let us know what you find out.   Thankfully most of the time the problem is the drive, and not the gear!   So it's a simple fix. :>)



Mike