Transmission stuck in 2nd gear.

[pehayes]

It looks like the bearing at the rear of the tranny where the rod for the clutch goes may have failed and come apart?

I stand to be corrected, but I'm not certain that a failed throwout bearing can push pieces inside the gearbox case.  I think they remain captive inside the bore of the rear cover.  Someone school me.

Inspect the rear cover carefully.  If the throwout bearing did disintegrate, its spinning steel pieces can do serious damage to the internal surface of the 22mm bore of the aluminum rear cover.  If the bore is damaged it will repeatedly tear up any o-ring that  you use to seal the outer body.  If damaged badly, the rear cover can be replaced or yours can be sleeved to restore the original bore dimension and smoothness.

Meanwhile, there is another radial thrust bearing on one of the shafts.  Perhaps the roller bits came from that one.  Do a careful inspection.

BTW, failure of either of these bearings shouldn't prevent shifting unless something (some part?) got jammed out of place.  I'll be curious to see why the shifting doesn't work.  I never  heard back about the possible binding of the shift linkage as it passes through the frame rail.    Also, the Guzzi is known to resist any shifting unless the internals are spinning.  Good to have someone turn the rear wheel by hand while you try shifting the system.  Once  you reassemble the box, it still won't shift on the bench unless you turn input or output shafts.

Patrick Hayes
Fremont CA

[n3303j]

I'm the fan of doing it the easy way.
Undo the input shaft nut.
Remove the selector detent ball and spring.
Undo all the back cover screws.
Prop the transmission, cover down on parallels.
Lift the main case off (note any shims)
The result looks like this image
Do repairs as necessary.
Stack the repaired parts on the back cover.
Drop the case over the assembled works.
Reinstall cover screws.
Reinstall input shaft nut (torque properly).
Done.

[nc43bsa]

Your problem of the transmission stuck in 2nd gear reminded me of this song from back in the fifties, Dusty would surely remember it...

https://www.youtube.com/watch?v=2skGMkxB6Ng

Without even clicking on the link I knew it was the song about the little Nash Rambler.   

[nc43bsa]

I have only had one 5-speed apart, and that one had a destroyed throwout bearing because the shaft bearing came apart.

[baxterday]

I stand to be corrected, but I'm not certain that a failed throwout bearing can push pieces inside the gearbox case.  I think they remain captive inside the bore of the rear cover.  Someone school me.

Inspect the rear cover carefully.  If the throwout bearing did disintegrate, its spinning steel pieces can do serious damage to the internal surface of the 22mm bore of the aluminum rear cover.  If the bore is damaged it will repeatedly tear up any o-ring that  you use to seal the outer body.  If damaged badly, the rear cover can be replaced or yours can be sleeved to restore the original bore dimension and smoothness.

Meanwhile, there is another radial thrust bearing on one of the shafts.  Perhaps the roller bits came from that one.  Do a careful inspection.

BTW, failure of either of these bearings shouldn't prevent shifting unless something (some part?) got jammed out of place.  I'll be curious to see why the shifting doesn't work.  I never  heard back about the possible binding of the shift linkage as it passes through the frame rail.    Also, the Guzzi is known to resist any shifting unless the internals are spinning.  Good to have someone turn the rear wheel by hand while you try shifting the system.  Once  you reassemble the box, it still won't shift on the bench unless you turn input or output shafts.

Patrick Hayes
Fremont CA

The shift linkage was fine, it went up and down without any binding and returned to where is should.  It just didn't move it out of what I think was second, could have been third.

[Tom H]

As mentioned already. Pics of where your at so far would be great. Especially the throw out bearing.

Tom

[baxterday]

Got the main input shaft out and it was easy.  I simply used a punch to tap on the nut with the four grooves in it since I don't have the tool.  When I say tap, that's all it took to loosen it.  I also discovered the locking washer had none of the tabs engaged.  I also believe it was installed upside down as the flat side was down and the domed side up.  I noticed the tabbed washer is concave to cradle the nut?  Maybe the washer became concave because it was so loose?  So the bearing that this shaft goes into in the cap end of the tranny disintegrated into the small pieces shown in the photos.  That is a dime for scale.  The end of the shaft still has the inner race attached and it is heavily grooved, not sure if it shows in the picture.  I believe that the problem is only the above described.  Nothing else looks out of whack.  I will of course replace the seals.  Thoughts and advise on moving forward?

[baxterday]

As mentioned already. Pics of where your at so far would be great. Especially the throw out bearing.

Tom

Tom,
Which one is the throw out bearing?  Is it the little needle bearing on the shaft that runs through the the tranny to the pressure plate?  It came apart when I pulled the shaft out. I just uploaded some more pictures.

[n3303j]

I think input shaft nut is supposed to be around 120 ft/lb.
I tend to think those roller bearings disintegrate running moly in transmission.
Check that input and output bearings have metal ball retainers.
If not replace them with bearings that do have metal ball retainers.



Check the selector return spring.

[Tom H]

In your 3rd picture. The locking washer is sitting on the table correctly. Flip the nut over so the tapered side is down. that is how it should go together. Yes the lock washer is sorta cup shaped and only 1 tab will line up with the slot in the nut.

The throw out/thrust bearing is the one on the end of the rod that goes through the trans and pushes on the clutch.

Your 5th pic looks like a destroyed bearing race. That could be where the bits of needle bearing are from rather than the throw out bearing.

Post a pic of the bearing that the destroyed race goes into please.

Tom

[n3303j]

That whole transmission roller bearing is scrap. The inner race pulls off the shaft. A blind puller will remove the outer race from the back cover. NAPA loans tools and probably has a blind puller, free! 123bearing stocks all the bearings at advantageous prices including the 22 ball, double race, radial thrust bearing used on the input and output ends. They deliver in a timely manner.

[baxterday]

Here is a picture of, or what's left of the bearing the destroyed race goes into.  The pieces found in the tranny came from this bearing. 

[n3303j]

You are lucky that the travelling bearing junk didn't lock up the transmission enroute and cause an accident.
Very thoroughly inspect every gear for tooth damage. Inspect every bearing for race damage. Bearing rollers are HARD and the bits will carve up anything that they get into.

[baxterday]

That whole transmission roller bearing is scrap. The inner race pulls off the shaft. A blind puller will remove the outer race from the back cover. NAPA loans tools and probably has a blind puller, free! 123bearing stocks all the bearings at advantageous prices including the 22 ball, double race, radial thrust bearing used on the input and output ends. They deliver in a timely manner.

Any idea what the part numbers are of the bearings on their website? 

[Tom H]

I'm sure you have read the tutorial on going through the trans on thisoldtractor web site. It has the bearing numbers listed in it. Also bearing cross reference: https://www.thisoldtractor.com/moto_guzzi_loopframe_transmission_bearing_cross-references_-_5_speeds.html

The tutorial is from a different model and shows O rings that are not likely to be in your trans. IIRR there is 2 under the input hub and 1  or 2 on the output shaft behind a gear.

123bearing appears to be a good source for all the bearings, I think they are in Europe. MG Cycle has the bearing your looking for I believe.

Tom

[n3303j]

The 22 ball input/output bearing was the scarce one.
Many sub an 18 ball double row bearing.
It has a lower radial load capacity.

I got all the bearing numbers off the bearings I removed.
I confirmed fit by comparing measurements against published dimensions.
I shopped for "best brand" when possible.
Price was not the consideration as labor (and reliability) is more important than a few dollars saved.

[baxterday]

A few more pictures of the inside of the tranny.  The layshaft bearing race in the front of the case is not flush with the case, should it be?  The main shaft bearing and clutch shaft bearing in the back of the tranny seem to be the same.  I was able to tap it out of the back case cover as it was protruding about 5 mm.  That and the thrust bearing on the clutch push rod as it came apart when I took it apart.  I just have to figure out how to get the race off the end of the shaft, I will be hitting napa for a puller. The main shaft bearing in the case has a little play, should I replace it too?  I am just going to get the parts from Harpers or MG.  See photos.  As I mentioned the nut with the locking tab was installed backwards and not tight at all.  I used about 5 pounds of pressure to get it to spin.  That can't be right.  Also no second oring present, only the one on the shaft.   

[Tom H]

Pic 4. You have the nut and lock washer correct. You also have one of the O rings shown. There is a second larger and thinner that slides past the installed O ring and sits just barely on the smooth shaft against the bearing. Right about where the smooth area is just behind the O ring shown.

If you have a heat gun. You can use that to warm up the case where a bearing goes and they usually will slide right out.

With the work it takes to get to where you are. Any bearings your in doubt of, might as well change them now. Or, just change them all, then you shouldn't need to for many many years.

Also while your in there. Is the rear main seal on the engine leaking? Now is the time to change it. BUT........To get the clutch assembled correctly, you need the correct tool to compress the pressure plate. BUT....BUT....There's more.... you can use the input hub as the tool. You just need a bolt that threads into the end of the crankshaft and a few washers. I think the bold is M12, but I do not remember the pitch at the moment.





Tom

[Antietam Classic Cycle]

Other things you'll want to check for and fix if necessary:

Intermediate shaft separation:




Indentations worn/hammered into the 5th gear inner bearing race:

[baxterday]

I think I know why the previous owners were in the tranny.  I noticed it has a new return spring.  I think they simply did not put the clutch shaft in correctly as evidenced by the loose and upside down nut and lack of locking it in place.  Everything else seem to be fine.  I am ordering bearings, gaskets and a few seals today.  With luck I will have her back on the road this weekend.  I am going to change out the stock airbox and replace with K&N's, like I have on my LeMans.

[pehayes]

You should put specified torque on the input and output shaft nuts.  In each case you'll need special holders.  Is there anyone nearby to you that could loan those holding tools?  Are you going back with the original 2mm clutch spline or moving up to the better 4mm clutch spline?  That determines what you use to hold the input shaft.  I can loan, but shipping from CAL would be expensive and delayed.  Must be someone closer.









Patrick Hayes
Fremont CA

[baxterday]

You should put specified torque on the input and output shaft nuts.  In each case you'll need special holders.  Is there anyone nearby to you that could loan those holding tools?  Are you going back with the original 2mm clutch spline or moving up to the better 4mm clutch spline?  That determines what you use to hold the input shaft.  I can loan, but shipping from CAL would be expensive and delayed.  Must be someone closer.









Patrick Hayes
Fremont CA

I am not sure what the clutch spline is you are talking about.  How do I determine which one is currently in the bike?  The actual clutch plate is fine, no issues there, and it may have been replaced when the return spring was changed to the three coil one.  They also installed the cups on the clutch rod backwards.

[Tom H]

On page 1 about 3/4 way down there is a pic. Looks like a deep input hub.

Baxterday,I posted a pic of the deep and shallow clutch hub earlier take a look at the pic.

You could try to use a strap wrench to hold the input hub and then the output shaft. Not the best, but should work.

Tom

[pehayes]

I am not sure what the clutch spline is you are talking about.  How do I determine which one is currently in the bike?  The actual clutch plate is fine, no issues there, and it may have been replaced when the return spring was changed to the three coil one.  They also installed the cups on the clutch rod backwards.

Talking about the input gear or spline on the front of the transmission.  That spline inserts into and is driven by the two clutch friction plates.  Your picture back on page one shows a deep spline = 4mm which is the newer/better spline.  Earlier bikes had a shallower = 2mm spline tooth depth.  Most people upgrade to the newer 4mm version if changing out the entire clutch.  I'm not sure if a 93 SP3 came originally at 4mm.  That was about the time of the design change.  While the newer plates and spline can fit older bikes, you can not mix 2mm plates with a 4mm spline.  Change all or change none.

What do you mean by "...cups on the clutch rod...".  Referring to two slightly tapered rubber seals?  Which way did you find them?  Picture?  Many people now abandon those two cup seals and substitute a stack of 5(?) o-rings instead.  See on Bender's site at:  https://www.thisoldtractor.com/moto_guzzi_loopframe_clutch_push_rod__installation.html

Patrick Hayes
Fremont CA

[Mechatoine]

I cant help with the transmission problem, but i see you are in Ellijay Ga.  Im between Chattanooga and Dalton.  About three miles from Georgia border in Tennessee.  Cool to have another Guzzi owner in the area.  Good luck with the fix!

I'm also in this area - Hixson, TN. We should all meet for coffee or beer one of these days.

[baxterday]

I'm also in this area - Hixson, TN. We should all meet for coffee or beer one of these days.

Definitely.  Let me get this beast back on the road.  I ordered the parts yesterday from MG, then realized I forgot a bearing for the clutch rod.  So, it was ordered today.  I hope to have everything Saturday.  Waiting on a part for the R100RS as well. At least the Aprilia is running. 

[baxterday]

Well my parts finally arrived after taking a detour to Knoxville via the USPS.  I believe I have everything needed to put it back together.  While examining things I noticed the fork on the shift lever, see pictures, was not springing back into position, there was metal shaving causing it to bind, see photos.  I took a feeler gauge and got the metal out and it seems to function as it should.  Could this also be why it would not shift out of gear? 

[pehayes]

Could this also be why it would not shift out of gear? 

Bingo!  Those teeth have to be out all the way in order to grasp and turn the shifting drum.  Nice that you now have a definitive target to blame.  Some of us have gone through all of this without finding a culprit and without knowing if it would work when reassembled.

Patrick Hayes
Fremont CA

[Tom H]

 

Tom

[baxterday]

Well, I have it back together finally.  I was taking my time just wanted to get it done right.  So far it seems good.  Going back in the bike next week.  Then the bike back on the road in time for the heat of summer.  Found a few bits of the bad bearing in the gears when I thought I had found everything.  I just hope it stands up to the pressure of being used.