BE WARNED - THE EXPERTS CAN GET IT WRONG!!

I may be needing that one day. Thank you!

 

Hence the "kick over the rock and see" approach favored under the repair shadetree:
If it doesn't loosen after a good "ummph", try turning it the other way.
(Learnt on old Mopar lug nuts.)

Expert: An "X" is an unknown quantity. A "spurt" is a drip under pressure.
An "X-Spurt" is an unknown drip, under pressure.

 

Based on my personal experience, when given such a situation and it wasn't coming off as it should using normal tools, I would try it in the other direction just to make sure before I went to extremes. But, like your experience, I learned that after I made the ONE mistake...because those damn mistakes are expensive!

Now you're the X-Spurt for this topic. Blog this experience or save this thread as a bookmark for proof

 

I'm not laughing and I've been "working" on cars for almost 40 years. Been there. Recently even!

So both halves of this assembly were threaded in the reverse orientation to other identical cars? That's evil.

Bob S.

 

No, that's Ferrari...

 

Tomo,

FC'ers no I'm not the hugest fan of pro wrneches but quite frankly nobody remembers or cares which way those nuts go. You see the nuts go on shaft and have a locking part that is peened into the shaft detent. The threads always stick out a bit past the lockrings by design. So all you need to do is look at the threads to see the pitch and direction. Further thinking about it and you can see which way they turn just like the pedal arms on your bike. Think basics and they will never fail you. If you know your basics you never have to worry about the choice of so called experts. They don't remember they operate on basic principals. "part replacers" try to remember which part goes where etc....

 

Buying a new ring nut would have helped too before removing the old one. The same logic applies to the other end of the shafts as well as knock off hubs, think of the shaft rotation and why they make them right and left hand threaded. I have a large thread on my 308 gearbox overhaul that would have shown you they are right and left threaded, if I had seen your post early enough I would have warned you.

 

I was under the impression that his was "different" than all the other cars. Or are you saying that he misinterpreted the advice? Just asking for a clarification.

 

So the nut was stuck and the direction of the threading was not relevant. You just said you tried it in both directions, it would not move, so you would have had to cut it off regardless of the mix up. BTW, expert means more likely correct than incorrect, unless you have a direct line to 1-800-Call-GOD.

 

Dont understand the part about all other cars? 308's, 246's, 328's and most likely all other f-cars will have left and right hand threaded shafts depending on direction of rotation.

 

If you look at his original statement he was implying that Ferrari had a quality control problem and reversed the direction of the threads the day his car was built and that it was different from others of the same model.

I just thought that would be very, very wierd. But what do I know?

 

Its not unique to his gearbox, its not unique at all and the guy that told him the wrong info must have had a brain fart but now it looks to me like he needs a new main shaft, not a cheap part. If it isnt replaced and the nut comes off it will make quite a mess.

 

"Wierd"?

...They would have to had reconfigure the maching mills with malevolent caprice.

The further implication is the factory were aware of this all along and made left and right cut lock rings as well as a "solution".

I would think the engineering of the gearbox would dictate thread direction with extreme prejudice, and perhaps observer orientation is the real fault in this system?

 

Sorry..."sound logic" always works just like my friend's ferrari gearbox apart in my garage right now. This is number 6 or 7 for me and I'm not a real mechanic. If you need some help don't get mad just ask. Newman and Southerncharm also gave some good advice. If you just "did" the basics, instead of just "I know a lot more than the basics!" you would see the thread direction. "Measure twice and cut once." I know you are mad, and I am not trying to be an a$$. I think after you cool off you will see that there have been some pretty valid points made by several posters even if you think I'm full of swamp gas.
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The WSM shows it as a left hand thread.
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Looks like the problem is in the parts manual.

It shows in the WSM that nut #25 is Left Hand & it also shows in the WSM that #6 is Left hand. This makes perfect sense as the mainshaft travels in the opposite direction of the layshaft.

In the parts manual “Nut #25” (in the WSM) = TAV27 #14 = #104252
In the parts manual “Nut #6” (in the WSM) = TAV26 #9 = #104253

Both parts should be LH thread?

From my experience #104252 = RH thread & #104253 = LH Thread

It looks like they have the wrong part numbers listed for the layshaft locknuts. Mainshaft looks OK.

Maybe an easy way of remembering is – Right hand thread on the splined end of the input shaft and diagonally opposed. Maybe easier to mod a drawing…..

Disclaimer: The above is only correct if what the WSM is stating!!! (But it defiantly looks like the parts manual is wrong!! – Actually thinking about the running rotation of the mainshaft (anti clockwise - looking onto the splined end) would make sense as the right hand thread of the nut would lock up with the shaft rotating in a anti-clock wise direction. ( And of course the lower drop nut that goes on the front of the mainshaft is RH thread as well!)

If this is the case – In defence of any Tech guy – if you look in the parts manual and get the number from the book – pull a part off the shelf and see that it is right handed and tell the customer its right handed – he has done his job to the best of his ability.I do agree with FBB that logic is always the best place to start but never stop at thinking outside the box !

Paul
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The workshop manuals are riddled with these types of errors... from the top of my head...

look up 246 camshaft cap torques

Look at the parts book for 246 engine mount and bracket orientation... ALL wrong

look at the parts book diagram for crankshaft thrust washers on 308 etc

I can't remember what it was now, but theres something in the 550 workshop manual for engines... When I re-built one it was quite clear, and this is a "new era" book.

Also, look at the parts book orientation for crankshaft main bearing shells for anything from 308 to 360... the grooved ones are shown to be in the cap, but never are when you strip an original engine...