[DeTomaso] Techno question: (second dumb question of the year)Speedo cable

MikeLDrew at aol.com MikeLDrew at aol.com
Sun Jan 2 20:47:00 EST 2011

In a message dated 1/2/11 16 00 39, cengles at cox.net writes:

>          Twenty years ago, I went through this scenario twice in short
> order.  The last repair has lasted 40k miles and twenty years.  I don't
> think that this is a common ZF problem.  
>>>It's not as uncommon as you'd hope, unfortunately.   The cause is the 
grease drying out inside the angle drive, and at some point it seizes, 
snapping the end off the drive gear.   Last year a friend in PCNC suffered an 
internally busted angle drive (which did no harm, the speed just stopped 
working), so he got a used one from Dennis Quella.   He installed it (properly), and 
just a few miles later, this new/used drive seized, snapping the speedo 
gear too.

To his credit, Dennis stepped up and supplied a brand new drive unit for 
the price difference between new and used, and gave him a replacement speedo 
drive gear for free.   That's not insignificant, because that animal is 
enormously expensive:


> > I suppose that I'll need another
> speedo shaft and speedo drive unit and proceed to reassemble.  Oh, well.

>>>It's worth mentioning that even though there is grave danger involved 
with incautious fiddling with the speedo drive gear, it *is* possible to 
remove and replace it without removing the gearbox from the car.   The danger is 
that it can drop down inside the gearbox, at which point it would be very 
difficult to retrieve.   When we changed the one in my driveway, we used vice 
grips to hang onto the sleeve that goes around the drive gear, and a strong 
magnet to hold onto the gear itself.   With the retaining bolt removed, we 
were able to pull up on both the sleeve and the gear together, and withdraw 
them as a unit.

Be patient, be careful, study the diagram carefully to understand the 
relationship between the various parts in the system:


and you should be fine.

Good luck!


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