My first Ribcase

[David W.]

I'm rebuilding a ribcase gearbox. I've done smooth cases before, and there is very little difference.
In the prior rebuilds, I did not take apart the syncro hubs. In this box, I found the detent springs and balls in the bottom of the box.
Is there a trick to holding those three springs and balls in place to get the ring on the hub? I spent an hour today trying. I'm doing it in a basin lined with a towel to catch flying balls and springs.
After an hour I've run out of ideas and rude words. Please reply with either.
David

[win]

Hi
I have found this is definitely a 2 man, OPPS, a 2 person operation.

My wife really enjoys this job, using small screwdrivers, or hard bent wire, to hold the balls in.

We should make this a new party game. The distance the balls fly, is directly proportional to the number of spare balls left.

Good luck. have fun

Regards Win

[David W.]

The ribcase I bought is a "rebuildable core."
When I started to dismantle it, I found bent springs and little balls inside. They are the detent springs/balls from the 1-2 hub.
I've got everything put back together, but I have the same problem that the previous owner had.
When I select first gear, the gear slides too far back and exposes the detent balls.
[frame][/frame]
Additionally, when selecting second, it doesn't go far enough to engage.
[frame][/frame]
The selector rod moves from detent to detent. Is there a selector rod where the detents are spaced differently?
It seems as if the selector fork could be designed to be a bit farther forward to make things work. Is there a part number I should be looking for? The fork installed has the number: 22A469 2-R3. This is the pn given for the fork in the 1098 gearbox at Moss.

[bmcecosse]

Hard to see from these pics - and many many years since I did one of these boxes. Is it possible for the fork to be wrong way round (I don't think so..) otherwise the whole gear /3rd motion shaft assembly is in the wrong place - look to see how that is located inside the casing.

[David W.]

The spring clip around the bearing of the first motion shaft defines its position. The 3-4 hub engages fully in each direction.
There is no slop between 2 and 3 gear. There is movement of the 1-2 hub on the output shaft, but that is by design.
I don't see where or how I could move the output shaft to the left by about a quarter inch.
My plan is to sit and stare at it for hours. Maybe I'll try some tea.

[bmcecosse]

Good idea - enjoying a cuppa right now myself......... Either the selector or the gears must be wrong.....

[les]

You could possibly use a piston ring assembly tool to insert the balls into the hub. I recently managed this without but took several attempts, if you get the 3 balls half way in position and press down hard on the outer ring, the balls stay there, you must then, whilst still pressing, push each ball in turn fully home, with a screwdriver, on the last one the outer ring should snap down into place. It's rather awkward switching your hands from ball insertion to pressing the outer ring without you know what happening!

[philthehill]

Have you made sure that the inner end of the fork securing screw (Wksp Manual illustration FF Part No 114) is fitted correctly in the register hole of the first/second selector rod?
It could be the tip of the screw is not correctly in the register hole as from the photo's the fork seems to move rearward in excess equal to its lack of forward movement.
The fork securing screw registered correctly (and locked with the lock nut) ensures that the fork only moves in accordance with the detents and therefore would not allow the balls and springs of the synchro hub to escape.

[David W.]

as from the photo's the fork seems to move rearward in excess equal to its lack of forward movement.

That's exactly it. I've got the securing screws right in the register. I've had them out several times to slide things around, and each time I eyeball the hole and make sure the setscrew is home.
The rearward and forward movement seem to be equally off. That makes me wonder if I got a gearbox with a hodgepodge of parts.
The part number I can read on the fork (22A469) is correct in the parts books, but I don't know what I have for the shift rod.
I'll be taking it apart next week to get the balls back in and start all over again.

[philthehill]

Having read the workshop manual again this morning and this is a qualified guess the wrong 1st/2nd speed synchronizer operating rod may have been fitted. It says nothing about different operating 1st/2nd operating forks.
See wksp man section FF6 titled Second Speed Synchronizer.
If you do not have the manual this is what it says.

To obviate self-disengagement of first gear a first speed gear and second speed synchronizer, with two thirds of the teeth relieved on the drive side is fitted as an assembly from Gearbox No D9176.
Should this assembly be fitted to gearboxes between numbers A2476 and D9175, it is important that the original first and second speed fork rod with the shallow first speed notch and plunger be fitted.
Introduced into this assembly from Engine No 129272 is a second speed synchronizer with the spring holes equally spaced, replacing the synchronizer with holes biased. This is to facilitate stationary first gear engagement.
A modified first speed wheel is used in gearboxes fitted to engines numbered from 266197 to 266400 and 266534 onwards; the number of teeth is reduced to 32 with improved tooth form.

Note the second paragraph! So reading the above there appears to have been at least two first/second speed fork operating rods fitted over a period of time.
Note also paragraph three. There were at least two synchromesh hubs fitted (biased/non biased spring holes) so therefore you could be right in that you have a gearbox built from a hodgepodge of parts. Get the right combo and I suspect that all will be well.

[bmcecosse]

Great research there Phil!

[philthehill]

One tries to be helpful.

As an aside it should not be too difficult to reproduce special tool 18G144 Synchromesh Assembly Ring as it is just as it says a machined ring.

[bmcecosse]

I have a distant memory of using (I think) a Jubilee clip.

[David W.]

Thanks, Phil, Great info here.
As for the three detent balls, I have that down now. I use a nylon wire tie and little screwdrivers.
But as to the syncro hub...
Some questions come to mind.
Which is the "drive side"?
"Spring holes equally spaced" means 120 degrees apart I assume, not fore and aft. How are they spaced on other hubs?
I'll have to examine the rod when I take it apart later this week and look for a "shallow first speed notch." That, however, only implies depth of that notch, not any change in the fork locating hole.
I do have the 32 tooth first gear wheel.
All this supports the hodgepodge theory.

[philthehill]

I believe that I am correct in saying that the drive side is the side facing the rear as the First Gear moves rearwards to engage with the first gear on the lay shaft as the drive for first gear comes through the input shaft (1st motion shaft) - lay shaft (2nd motion shaft) - 1st gear and then out through the back of the gearbox (3rd motion shaft).
In wksp manual illustration on page FF4 the springs/balls in the 1st/2nd gear synchro hub are biased towards the 2nd gear. and later synchro hubs after engine No 129272 the holes are equally spaced (or half way along the synchro hub). The spring/ball position remain at 120 degrees apart. Without measurement but looking at your pictures of the synchro hub in your problem gearbox the balls/springs appear to be centrally placed or non biased as they should be for a later gearbox.
The more I think about it the more I am convinced that the 1st/2nd gear operating rod is the problem.
Working backwards - When you have assembled the gearbox and the synchro hub is central between 1st and 2nd gear as if in neutral do the cut outs in the rods in which the control lever (item 8 in illustration FFF2) align as they should do or is the cut out for the 1st/2nd operating rod displaced. If it does not align with the others then that confirms that the rod is the problem.

[David W.]

Here's what I got from a transmission guy over here, although 1500 miles from me. I can't yet visualize where he wants the shim, it seems as his description would make the problem worse.
As for what he says in paragraph 2, I've got that under control. .

David - Hi and thanks for your inquiry.

This is a common problem with the rib case transmissions. The mainshaft alignment is incorrect. There are two items that can cause these problems:

1. The mainshaft is too far forward. This is usually caused by incorrect shimming of the main case or center bearing. the original bearings are no longer available so the new bearings have shims included to set the mainshaft alignment correctly. If there are too many shims added in front of the inner race of the bearing (between the inner race of the bearing and the mainshaft splines for the 1st gear hub) the mainshaft will be too far forward. This misalignment causes exactly the symptons you descibe. An additional symptom is the 3rd/4th sliding hub clearance will be too tight between the 3rd and 4th gears - again because the mainshaft is too far forward.

If you have an original bearing no shims are required. If you have a new replacement bearing then the shims required in front of the bearing will be between .040 and .050 to achieve proper mainshaft alignment.

2. In addition be sure you have the small detent plunger that fits into a hole on the inside of the inner hub of the 1st gear assembly. This detent locks the inner hub in place on the mainshaft when shifting into 1st and 2nd. The outer hub has a slot in one of the ramps that must be properly aligned with this inner hub detent for the hub to function properly. This detent can also cause the problems you are encountering if missing or not properly aligned.

Let me kow what you find!
n
Thanks! john esposito

Quantum Mechanics Ltd.
315 Riggs Street, Building A, Suite 3
Oxford, Ct. 06478
Phone 203-463-8299
Fax - 203-828-6039
website www.quantumechanics.com
email - john@quantumechanics.com

[David W.]

John at Quantum Mechanics was spot on.
I'll bet nobody else knows that the new bearings you get for a rebuild are different from the old bearings. The inner race of the old ones is about .100 longer than the outer race, .050 in each direction.
I got two new bearings, front and rear. They were unmarked as to front or rear. I measured them, and all dimensions were the same, so I thought, what's the difference. One of them had a washer with it. I didn't think shim, I thought washer and put it in front of the front bearing like all the parts diagrams and OH manuals show.
None of the manuals show or mention a shim. They were written long before the problem arose.
Putting a new and old bearing next to each other, and you can see the difference.
Another thing I did wrong was not using the snap ring around the outer race of the new bearing. The new bearings arrived, one had the snap ring in place and the shim. Naturally, thinking the shim was only a washer, I put the bearing with the snap ring up front with the washer as shown in all the diagrams.
With the shim, and the snap ring where they should be, everything fits in its place.
I've got the mainshaft back in, and set up the 1-2 fork and rod, and all the detents line up and everything seems right with the hub springs and balls.
The 3-4 hub also looks a little more symmetrical in neutral.
The rest of the reassembly can wait until tomorrow. Too hot in Florida.
John at Quantum Mechanics has a good website. He wants me to tell you all that he encourages any questions you may have. If his advice here has helped or might help in the future, drop him an email and let him know we appreciate his generosity.
John Esposito
Quantum Mechanics Ltd.
315 Riggs Street, Building A, Suite 3
Oxford, Ct. 06478
Phone 203-463-8299
Fax - 203-828-6039
website http://www.quantumechanics.com
email - john@quantumechanics.com

[philthehill]

A good result.
It was that new size bearing that caught me out as I assumed that the bearing was original and there was no information to think otherwise.
I note that the Main shaft bearing available from Bull Motif Spares Part Number 10G184 includes a washer but no additional information regarding the use of the washer.

[bmcecosse]

Well done indeed - and well done 'Quantum Mechanics' - bit advanced for a Morris Minor.......I would have thought...

[les]

Yes thanks for sharing that info, I've had an occasional issue with my box not selecting 4th, in fact I can drive for many miles with no selection difficulties then maybe find 4th won't go in, back to 3rd, try again and usually ok. Never been a real issue but maybe worth contacting that company some time.