[DeTomaso] transaxle

[MikeLDrew at aol.com]

In a message dated 11/10/15 13 31 35, tcabanski at tencom.com writes:


> Have always heard an occasionally clunk when I'm waiting at a stop light
> with the car in neutral.
> 
> Thought it was a bad universal joint, but checking them seems to show
> they are good & tight.
> 
>>>Hmm, I wouldn't suspect U-joints if the car is stationary.
> 
> >I now think that the ring gear bolts are loose or that one or more of
> the bolt heads may have sheared off.
> 
> They have not been safety wired.
> 
Is there an easy way to confirm?

Look for shaving on the bottom drain plug on in the gear oil?

Can you remove the anything while it is in the car to confirm?

>>>There is a way to inspect for ring gear bolt problems without taking the 
gearbox out of the car, but it requires the use of a flexible inspection 
camera.   These things have become popular and cheap in the past few years, 
and can be had from various retail sources like Costco, auto parts stores, 
etc.

If you're lucky you have a friend who owns one already!

You can use it to inspect the bolts through the drain plug hole.   You 
remove the plug and drain the fluid (and if it's not fresh, now is a good time 
to change it).   

The failure mode here is that the bolts loosen up and slowly unthread 
themselves.   There is a shelf on the inside of the case and eventually the bolt 
head strikes that shelf and snaps off, turning the bolt into a stud that 
isn't securing anything anymore.

You can't actually see the head of the bolts through the drain plug 
opening.   What you see instead is the other end of the bolt.   Attached is a photo 
of a gearbox with the cover removed, viewed from the side.   You can see 
that three of the bolt ends are visible, and one is not.   That bolt 
unthreaded itself, and the bottom portion is still in the hole (but not visible) 
while the top portion was missing.

Of course, all other things being equal, when you drain the oil, the bolt 
heads will likely fall into the drain pan, which is a bit hint!   If that 
happens you don't need to bother with the inspection camera--it's gearbox-out 
time.

The type of noise you describe is not what I would attributed to this 
problem however.   Normally there are no indications of this failure, unless the 
bolt head gets caught up in the ring and pinion, and blows the gearbox sky 
high.   Without being there to hear it, I would suspect that the noise you're 
hearing is a throwout bearing, or (worst case) a mainshaft bearing inside 
the gearbox....

Let us know what you find out!

Mike
-------------- next part --------------
   In a message dated 11/10/15 13 31 35, tcabanski at tencom.com writes:

     Have always heard an occasionally clunk when I'm waiting at a stop
     light
     with the car in neutral.
     Thought it was a bad universal joint, but checking them seems to
     show
     they are good & tight.

   >>>Hmm, I wouldn't suspect U-joints if the car is stationary.

     >I now think that the ring gear bolts are loose or that one or more
     of
     the bolt heads may have sheared off.
     They have not been safety wired.

   Is there an easy way to confirm?
   Look for shaving on the bottom drain plug on in the gear oil?
   Can you remove the anything while it is in the car to confirm?
   >>>There is a way to inspect for ring gear bolt problems without taking
   the gearbox out of the car, but it requires the use of a flexible
   inspection camera.  These things have become popular and cheap in the
   past few years, and can be had from various retail sources like Costco,
   auto parts stores, etc.
   If you're lucky you have a friend who owns one already!
   You can use it to inspect the bolts through the drain plug hole.  You
   remove the plug and drain the fluid (and if it's not fresh, now is a
   good time to change it).
   The failure mode here is that the bolts loosen up and slowly unthread
   themselves.  There is a shelf on the inside of the case and eventually
   the bolt head strikes that shelf and snaps off, turning the bolt into a
   stud that isn't securing anything anymore.
   You can't actually see the head of the bolts through the drain plug
   opening.  What you see instead is the other end of the bolt.  Attached
   is a photo of a gearbox with the cover removed, viewed from the side.
   You can see that three of the bolt ends are visible, and one is not.
   That bolt unthreaded itself, and the bottom portion is still in the
   hole (but not visible) while the top portion was missing.
   Of course, all other things being equal, when you drain the oil, the
   bolt heads will likely fall into the drain pan, which is a bit hint!
   If that happens you don't need to bother with the inspection
   camera--it's gearbox-out time.
   The type of noise you describe is not what I would attributed to this
   problem however.  Normally there are no indications of this failure,
   unless the bolt head gets caught up in the ring and pinion, and blows
   the gearbox sky high.  Without being there to hear it, I would suspect
   that the noise you're hearing is a throwout bearing, or (worst case) a
   mainshaft bearing inside the gearbox....
   Let us know what you find out!
   Mike
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