I'll start over. I have been seeing breaking up ball spacers but these last two are the worst. The teeth I suspect were developing a wear pattern as the shafts were able to move further apart. As it turned out just about every gear suffered a broken or chipped tooth. I'm thinking poor installation of the bearing at the factory was not the problem. As I pulled it apart all bearing on the main shaft had failed to some degree. The duel element ball bearing was trashed. The first to third motion needle bearing was gone and the spigot on third and bore on first motion shafts were badly damaged. The fitst motion large ball bearing was beginning to break up. Can't say much about the first motion outer support bearing. It appears to be OK as does the outer race. I will remove the race and check for signs of movement.

I started building trannys as a hobby when I was 12 years old. When I returned from the Army I began rebuilding trannys for Seven Ent. Then as now I had one rule either we repair it correctly ( which is my call ) or I box and return it. At that time I was getting $125. plus parts for a rebuild. And that was for remotes which eat up more time. I buy the best quality parts and spend a great deal of time making sure every thing is as close to spec as is possible. I have come up with ways to machine cases and housings to set clearances. I have installed A+ gears in pre A+ boxes. I have assembled 5 Swift Dog boxes and countless JKD dogs. I came up with a way to weld the first/second shift fork and machine to to clear the JKD dog gears. There were two forks, now only one. The JKD dog was designed before the second fork came out.

Yes, I have been building trannys for a long time but I'm thinking that's not a bad thing for a customer. I currently have on hand a NOS JDK involute gear set and a Swift dog set both new in the boxes they came in. I have my tranny bench and parts shelves a whole area for nothing but tranny rebuilding. My years at the machine shop have left me with access to machines and equipment others don't. I rebush all diff. side covers and align hone them to min. clearance. All cases are cleaned glass beaded and cleaned several times again. Any glass beads at all would kill a new tranny. Care must be taken to insure all beads are out. I have a bucket of bolts I keep and install in all threaded holes in a case. Then I glass bead and start the cleaning process. I also offer a fin welding and repair service. When a batch of diff pins or lay shafts come in we Rockwell test them. 

Now would a KAD bearing support have saved this problem? I'm thinking there are very few people who would spring for one. I have never opened a tranny and found one in there. You would think once a CNC program was complete they could spit them out a little more cheaply. I work with a couple of local job shops. They mostly were doing NASA work till that dried up. When we do a one off it's expensive but 1000 brings the price right down. Is there a market for 1000 I don't think so. Surely not at that price. The guy from Canada was making them out of steel plate. I can see making one that would be fine for a street application. As far a 1st and 2nd level of quality parts we have had that for years. There are OE parts and aftermarket. Big price difference. And yes people ask is it worth the price? If you can get to it and replace it in less than a hour maybe. Other wise go with the good. At the Mid Ohio race Calver who seems to have MSC's ear thinks the OE and aftermarket are coming out of the same bag these days. Does that mean take your chances with the cheaper? I don't know, what I do know is rebuilding a quality tranny is getting to be harder. Mine are not cheap but they do perform. Who said quality pays it does not cost? Steve (CTR)

years ago, I posted on this forum my experience with a pressure fed layshaft modification and was taken to task by a board member who designs transmissions (or used to) for a living. I was schooled on why it was a bad idea. It was VERY easy to do, as you see here. Other versions of pressure fed layshafts I've seen had the pressure line external to the engine/trans and the line passed through the case. This suggestion pictured below by a master mechanic worked very well and was tidy and we didn't have to drill any external holes in the case.

Perhaps being a little overzealous, we SIMULTANEOUSLY did a cage-delete on the layshaft bearings-- we used the early style individual needle bearing setup (which admittedly at the time I was skeptical about anyways). This was a 3-syncro, SC/CR box.

the result was a destroyed brand new custom super-hardened 3-syncro layshaft in very short order.

After the discovery of the damaged layshaft follwing the transmission mods pictured above and following only 1 race or about 14 hours of track time under a NA 58hp 998, the commentary (as best as I can remember) was that needle roller bearings don't like to be pressure fed and prefer just a "Splash or mist" of oil versus pressure. Additionally, the cageless roller bearings are also more apt to slide rather than spin. So the combination of the pressure feeding (which would prompt the bearings to slide and not spin) AND lacking the cage (again, prompting the bearings to slide and not spin) I was told was a recipe for disaster. The advice was that IF I attempt it again, do one OR the other, but not both.

Since then, I only ran the setup (with a new layshaft) with both presure feed and cageless bearings for about 1 hour for motor break-in and then I pulled the engine and have since removed the pressure feed tube (since it was the easiest thing to do) and have not actually run or checked that transmission again since. 

I wish I could find that darned thread again. It was also posted on the vintage mini racing site. Maybe the commentary was over there and not here... Damn memory!

Jeg, I'm going to push your idea of offering as you say a "luxury line" when premium parts are available along side the ones for "the masses".   As more people realize or accept, the Mini is becoming a rare and exotic car with considerable value measured in multiples of it's original cost.  The point has been made that the cars were so cheap to buy that there is great resistance to expensive parts on par with say a BMW MINI...  It's funny, but Classic Mini owners that also have a MINI never complain about the cost of parts... not for the classic anyway!

A quick note, I have removed a number of posts, both mine and Steve's.  What I do on this forum is not really my job, and I'm not required to be on here helping people as I do.  If you've ever talked to me, you know very well that I'm polite, well thought out, and willing to help people without any personal gain.  A weakness is my inability to let what I perceive as a wrong, or a misunderstanding go without a rebuttal, but that obviously can get personal and go downhill quick! I went home for lunch and picked up my afternoon dog, and did not like the bad taste left in my mouth.  I haven't had time yet, but I'll try to talk to Steve about our differences "off air".

Have a nice weekend all!

Message taken - clean, inspect, measure, check, double check, beware previos mods, shim for preload...build a happy box.

Years ago, we had a box built by a Board Member (an early remote A box) to go under an MG Metro 1275 with a few mods.  Layshaft was pressurized.  We couldn't break the box even with race approaching rpms.  Nor could the later owner, who regulary abused the Mini.

Almost 10 years ago another local Mini mechanic rebuilt the A+ box (that had been under the original late to Canada 998) to go under the 1380 build.  Could not break that either but did crack an inboard CV cage showing my heels to a hard charging vehicle determined to run me off the approach to the Fraser Over the Fraser bridge...Mini shot ahead as intended.  Days later the cage broke and I lost my balls close to home.

I'm sold on building a transmission to last.

Having very nearly suffered this failure (see earlier post) I'd have to disagree.  There are no warning signs or symptoms from inside the car.
I was lucky - lucky that it was a low power standard 998 and lucky that I heard the bearing breaking up and recognised it for what it was.  The car did 2.2 miles after the discovery before stripdown.

Yup - we're happily on the same side. 

But not all of us have access to a Rockwell test rig and we collect the best parts we're able to and put them in a box waiting for a weekend away from the wife where we'll be able to do that pesky repair (fx. clutch) job.  If, when we buy these parts from the major 'mainstream' suppliers, we knew that they're 'soft' or otherwise substandard in some way, then we could omit them from our inital order and order them separately from the specialists; in this case, KAD.  When I order parts, it's oftentimes 'some of this, some of that, and one of those because it's on sale andI can use it later - just in case) in order to maximize the shipping and tax expenses.  Geography and governmental policies pretty much prohibit that I order parts from our host, but I'm a steady customer at MSC.

As a suggestion, our host (all the major suppliers, for that matter) could perhaps offer 'the luxury line' of products from the specialists along side the standard sourced components as our host has with this speedo drive housing - without us needing to know that the parts exist in the first place.  In the example given previously, the KAD007 could have been refered to directly from the  88G207 webpage.  If I were building a gearbox, I'd add it to my purchase if it was refered to as an alternative upgrade to the standard component.  T'would help let me know that this was an option, as I haven't been on the KAD website for ages.

Example:

From the MSC website: 22A180MS right under the image, there's a link to 'alternatives' which scrolls down to an upgraded EN24 22A180  version of the same component.

Another: C-22A2204MS gives the alternative link to the exotic C-22A2204 (drool).  And it's the same with the throwout bearings and other parts. 

And, believe me, the MSC website has it's faults - the search function drives me crazy sometimes, but it educates me at the same time by offering the upgraded parts that I never knew existed..

I'm not suggesting that our host or others increase inventory, just add an 'alternatives' link to the existing parts page when a new product becomes part of the assortment. 

Just my 2 cents -

What I'm "on about" is that I too have disassembles tons of gearboxes and am sharing what I've found AND providing a possible explanation of the cause.  Sorry Steve, but I DO NOT take a "here say" or what I might call an "old wives tale" approach to a problem.  I use my experience along with an understanding of how things work and how they fail.  I've noticed over the years that you tend to make very general statements when dealing with specific problems.... things like "All A+ second gears must be weaker" when actually it is more to do with how most are used and that more of them are under powerful 1275 and bigger engines.

Also, we were talking on Jeg's post about the ever declining quality of replacement components, and that brought up the view that Classic Mini people are "cheap" and will for the most part buy the very cheapest part they can find and then gripe about quality.  So I issued a challenge using the fantastic (and expensive) KAD Speedo housing with the extra mainshaft support bearing. 

Granted it's not exactly apples to apples, but after seeing the photos of the destruction you found, it is quite obvious that that driver was either hell bent on complete destruction, or just an idiot to keep driving that poor thing as it undoubtedly tried hard to let him know something was terribly wrong. It's a bit too late to blame that mess on bearing quality!

Jeg.... agreed, the KAD item is hardly a replacement part, but I maintain that a very specific vacuum advance curve is too much to expect... Imagine the Buyers dealing with China... 'Yes we need to make these distributor vacuum units'... how likely is it that either they or the Chinese manufacturers would take into account or even understand the subtle differences in advance curves!  Sometimes, we're just lucky they bother to make them at all.  They don't bother marking them because they're all the same!  Is there ANY chance at all that the people farming this stuff to China are like you, me, or Steve?  They are clueless about the material specifications of say a rotor, so you get ones that "look" right, but turn into silly putty when subjected to real world use. Do you think there's any chance that inspectors check things like the Rockwell hardness of diff pins, or spring diaphragm throw-out bearing pads?  Nope!  Sadly it becomes more and more the responsibility of the installer to be knowledgeable, and that's exactly what we are doing here... Sharing knowledge!!  I just wish Steve would take a less antagonistic approach... We are on the same side!

Thanks, I'm not sure what Jemal is on about. I was not complaining these I suspect are OE parts in service since the unit was new. I buy trannys and when I get something like this it hurts. Nothing but the drop gears appear good and I'll need to clean them up and do some checking before I know if I can save them. All the gears suffered chipped teeth if not missing ones. As I said I have had ones with broken ball spacers but thiis is only the second one driven to complete drive failure. I have another slated to come in with a lost drive issue. Being an injected Jap spec AC car it will be a fun job. Steve (CTR)

Image Gallery

Posting photos for Steve.

"It should help prevent the pinion from "walking" over the crownwheel by supporting the pinion end of the mainshaft OUTBOARD of the pinion, instead of the 3rd motion bearing taking all the load from one side.  Here's a chance for some of you that complain about crappy parts to put your money where your mouth is and support a manufacturer that is engineering top quality parts!!  Yes it costs half what an ENTIRE Mini did in the sixties, but do we want quality parts or not?   I'll bet more people would buy a future Chinese copy for $150 then gripe about crappy quality!!  Do you see how we contribute to the demise of quality components without realizing it?"

Jemal, I feel your pain, and I agree.  But - this is hardly a routine service part.  A bit different to a 'soft' dizzy rotor or melting contact breaker points heel (or unmarked vacuum advance unit) or whatever else we've griped about. 

Oh robster......!

guys, i have a question, in behalf  of all other newbies?

what do you guys mean by "tranny"?  and "dizzy"???

This is a well known issue and not a sudden surprise.

Rover swapped to a ¾ cage main double roller for a while, chasing reduced friction and better economy, and they are notorious for breaking up.  Metros and Metro boxes are the worst.
I had one go on Betty and was lucky to catch it in time.  While changing a pot joint boot I turned the joint to hook the gaiter on and heard something I can only liken to a Newtons Cradle.  With an ear pressed to the sump I could hear the balls climbing up the cage as the mainshaft turned then falling back down when I stopped the rotation.
If I'd carried on driving with it like that, it is far from unknown for the balls to catch each other up, jam, and then all hell breaks loose.

I'd be curious how long the bearing had been in service, AND whether it had the proper preload set via proper shimming of the bearing retainer.  It seems as the specific knowledge of these boxes slips into the past, people (at shops too!) just assemble the components in a "that looks right" way without proper attention to critical details.  A few weeks ago I had an irate guy at a shop complaining about a failed diff after they rebuilt the gearbox. when I tried to quiz him about how they set it up, he said "man, I don't use gaskets on aluminum cases".  I said "man, I think we've found the problem! Are your diff bearings blue?"

If the double roller 3rd motion bearing is allowed to flop back and forth in it's bore ( as can happen when NO shims are used behind the retainer), you bet the plastic cage will fail quick!

I wouldn't be much of salesman if I didn't try to point you to a solution! I'm building another very special close ratio, big shaft, rod-change box for the over-powered 1380 in my 66 S, and I plan to use this spiffy new part from KAD:

//www.minimania.com/part/KAD007/Kad-Pinion-Support-Bearing-Housing-For-4-5-Speed-Gearboxes

It should help prevent the pinion from "walking" over the crownwheel by supporting the pinion end of the mainshaft OUTBOARD of the pinion, instead of the 3rd motion bearing taking all the load from one side.  Here's a chance for some of you that complain about crappy parts to put your money where your mouth is and support a manufacturer that is engineering top quality parts!!  Yes it costs half what an ENTIRE Mini did in the sixties, but do we want quality parts or not?   I'll bet more people would buy a future Chinese copy for $150 then gripe about crappy quality!!  Do you see how we contribute to the demise of quality components without realizing it?

All I have had issue with have been DAM 5626 late big idler rods. One was a 998 the other 1275 on the ones completely blown apart. Yes third motion shaft double ball bearing, kills the case bore when it goes. Last one shattered the bearing retainer. Steve (CTR)

Yup. I've had to repair over a dozen transmissions because of the plastic cage in the double roller bearing breaks up and bearings fall to one side and mainshaft pushes away and kerboom

It is pretty common in MPI cars from what I hear. My experience with this has been mostly in rod change boxes with a bias of more towards later A+ boxes. But I've seen a few with broken bronze cages in remote boxes, too. If I had to pull a % out of my butt, I'd say 5% were in remote boxes, 25% were in pre A+ rod change boxes, 70% were in A+boxes (and I'm sorry I can't break that down between big and little idler or 4 vs 3 bolt retainer cases-- can't even venture a guess at that separation).

An excellent and more accomplished mechanic told me what he does when he has a mini on the lift and has drained the oil, he will rotate the wheel and hence the transmisison very slowly and listen for the ball bearings "tick" as they first slowly climb up the race and then fall down from the top to collide against the other bearings that are in the race because there is no cage to keep them separated and evenly spaced.  

Oh, and it's typically the cage on the gear side that breaks up first and, if you're lucky, the cage on the pinion and speedo gear side is still intact.

Steve, Are you talking about the 3rd motion shaft (double) ball bearing in the center web? I hope not, or we have another item to add to the "Crap Parts" list, and a very serioius one. On all the gearboxes I've done I've not seen damage to the extent you mention because of that bearing's failure. But I haven't done a gear box for a year or so and the last one was a 3-synchro remote.

were they both rod change transmissions?

I do a few trannys as it has been something I have liked since I was a 12 year old kid. Those who have been into a mini tranny have run into a worn diff. pin. When that pin fails and parts the spider gears fracture and drive is lost. While I have run into trannys with mainshaft ball bearing separators that had begun to break up, I'm seeing something new. I have now torn down two units where the balls have all moved to one side allowing the main shaft to run off center. Once it gets to the point where pinion rides over the tips of the crown wheel teeth the duel element third motion ball bearing fractures the outer race dumping the balls into the bottom of the case and all drive is lost. The speedo drive gets busted out of the tranny front speedo housing. The main shaft and all it's gears are damaged as well as lay shaft, forks and case. I will see if I can get some pictures posted. Steve (CTR)