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Old 11-01-2012, 12:47 PM   #1 (permalink)
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Transmission Circlip Failure

Since Mr. D. likes to bring on reason for failures this one seems to haunt 'us'

The inputshaft of the tranny decides to 'mindmeld' with the crankshaft. It's been known to be a common problem and can anyone offer advice as to what to look for before this problem happens? The damage can cost thousands.

Mr. D. I'm not trying to steal your thread concept but there are 'larger factors' going on here.
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Old 11-02-2012, 04:23 AM   #2 (permalink)
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Id like to know too. From some comments, it appears that there is little warning and it basically just goes poof. That kind of sucks but what are ya gona do? Replace the thing every other year? My car has 60K on it and that bearing was replaced at about 25K. So, who knows, I could have 10's of thousands of miles left or it could fail any minute. Whatever.

I think you can do some things to better your chances of avoiding it. The usual stuff like:

1) Taking foot off the pedal at stop lights
2) No musclecar power shifting
3) Smooth transmission operation
4) No drag race launches
5) Smooth/throttle blip downshifts
6) Minimum stop and go driving

Im curious though - there MUST be some warning sign...????
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Old 11-02-2012, 05:09 AM   #3 (permalink)
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Makes sense to me that there's no warning. It's a little clip that let's go and then bang! If a little clip is giving off any warning sounds, you'd wouldn't hear it over the engine and gearbox noise.

From what I've read, it seems like changing it ever 50k miles is a good idea.

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Old 11-02-2012, 10:21 AM   #4 (permalink)
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Originally Posted by Type82 View Post
Since Mr. D. likes to bring on reason for failures this one seems to haunt 'us'

The inputshaft of the tranny decides to 'mindmeld' with the crankshaft. It's been known to be a common problem and can anyone offer advice as to what to look for before this problem happens? The damage can cost thousands.

Mr. D. I'm not trying to steal your thread concept but there are 'larger factors' going on here.

Hi , I asume you mean the circlip wich holds the inputshaft inside the primairy shaft? This is only for the Citroen tranny.
Springload is pretty much and after many years the circlip fails and the input shaft will works it way into the cranck shaft. Transmission has to be taken apart to replace the circlip. I have modified and much stronger circlip. Will never fail.
Upgrading your flywheel with ballbearing is also option.

with kind regarDSm,


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Old 11-02-2012, 10:55 AM   #5 (permalink)
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Originally Posted by s2mikey View Post
Id like to know too. From some comments, it appears that there is little warning and it basically just goes poof. [snip]
Im curious though - there MUST be some warning sign...????
Carbuff (Atwell) is fixing his 88 Esprit right now - no warning whatsoever.

Other postings from others mention some hard shifting - I can live with a warning, but if it's like random and leaves me stranded without warning - that really is painful.

So far, my understanding is the 'true' fix is to machine the crankshaft for a proper pilot bearing ($$$) as the crankshaft has to come out of the engine.

I've heard mention of a 'super circlip' - while I normally don't advocate short cuts, I'm open to hearing the advantages/disadvantages of this 'super circlip'.
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Old 11-02-2012, 11:08 AM   #6 (permalink)
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[snip]Transmission has to be taken apart to replace the circlip. I have modified and much stronger circlip. Will never fail.
Upgrading your flywheel with ballbearing is also option.
[snip]
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Could you show pictures of this circlip? Did you mean the transmission had to be removed from the engine? Or truly 'taken apart' - transmission case must be opened to replace circlip?
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Old 11-02-2012, 02:33 PM   #7 (permalink)
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Originally Posted by lotusespritse View Post
Makes sense to me that there's no warning. It's a little clip that let's go and then bang! If a little clip is giving off any warning sounds, you'd wouldn't hear it over the engine and gearbox noise.

From what I've read, it seems like changing it ever 50k miles is a good idea.

My clutch was replaced under 5k miles ago.. Should I assume this was replaced?
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Old 11-02-2012, 03:08 PM   #8 (permalink)
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Quote:
Originally Posted by Sburke View Post
My clutch was replaced under 5k miles ago.. Should I assume this was replaced?
This is only on the 88 and earlier cars with the Citroen transmission.
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Old 11-02-2012, 03:29 PM   #9 (permalink)
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Could you show pictures of this circlip? Did you mean the transmission had to be removed from the engine? Or truly 'taken apart' - transmission case must be opened to replace circlip?

Hi, I mean truly take apart and removal of primairy shaft.


I have not figured out yet how to post photo's yet but if you send me a message I can send you some.

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Old 11-02-2012, 03:54 PM   #10 (permalink)
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Yes Harry,
The clip I'm talking about let's go and the input shaft pushes into the crank {from spring pressure?} Somewhere I remember reading they used nylon thrust washers which wear out causing play in the shaft which wears out the circlip and let's it push forward into the crank. Could you comment on that if I am correct?

I know you are the Guru for these Citroen transmissions who everyone turns to.

Thank you for your help.
Robert

Last edited by Type82; 11-02-2012 at 04:03 PM.
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Old 11-02-2012, 08:52 PM   #11 (permalink)
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There is no easy fix for this problem but the upgraded c-clip is the least complicated remedy even though you still have to remove the gearbox and open it up.

Keep in mind that in order to do the second option of actually putting a pilot bearing in the crankshaft, you have to completely tear down the motor and remove the crank to have it machined for the bearing. This is the best option if you have to rebuild an engine but otherwise, just get the upgraded c-clip and quit worrying about it...

For those that don't know, Harry is THE authority and source for Citroen gearboxes and parts. If he says it works, it works.
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Old 11-02-2012, 10:58 PM   #12 (permalink)
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Hi, uploaded some photos in the gallery.
Problem mostly happens with the Turbo Esprits. You can see the differ in angle.

cheers,

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Old 11-02-2012, 10:59 PM   #13 (permalink)
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Le Giugiaro Citroen Gearbox - circlip inputshaft LotusTalk Lotus Gallery
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Old 11-03-2012, 07:35 AM   #14 (permalink)
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Sounds like the best advice would be to pull the transmission every 50,000 miles, do a clutch replacement and replace the circlip at the same time with the uprated circlip. If the motor should need major service then at that time it would be a good idea to have the crank machined for the ball bearing. The crank can be removed without completely tearing the motor apart by leaving the head on and carefully removing the bottom end (assuming the top end is not in need of any service). Using this advice as a guide, any '88 with the Citroen box that has more than 50,000 miles on it (and does not have either the ball bearing in the crank or the uprated circlip) needs to have the transmission removed, the clutch replaced, and the circlip replaced. This is especially important advice for any prospective buyer. He needs to figure this cost into his offer. Much cheaper to be pro-active on this. The consequences of circlip failure are the complete rebuilding of the motor AND the transmission. Much more costly than a clutch replacement.
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Old 11-03-2012, 09:43 AM   #15 (permalink)
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Quote:
Originally Posted by dsvitesse1;1810954[snip
You can see the differ in angle.
[snip]
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It's a bit difficult without captions, but from what I remember on other postings,the S1/S2 shaft has a more pronounced 'lip' and that lip was reduced for the Turbo Esprit (out of concern for forming a stress riser (?)).

The HML remanufactured circlip looks like it's flattened and shaved on one side. Is there any special installation modifications or is it a drop in fit?

Thanks,

Eddie
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Old 11-03-2012, 10:22 AM   #16 (permalink)
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Originally Posted by Type82 View Post
Yes Harry,
The clip I'm talking about let's go and the input shaft pushes into the crank {from spring pressure?} Somewhere I remember reading they used nylon thrust washers which wear out causing play in the shaft which wears out the circlip and let's it push forward into the crank. Could you comment on that if I am correct?

I know you are the Guru for these Citroen transmissions who everyone turns to.

Thank you for your help.
Robert
Surprised Harry didnt mention this, the nylon trust washer that is on the clutch end of the imput shaft will eventually wear and or disintergrate either speeding up or actually causing the demise of the circlip.

There is a fellow in England who sells the Nylon Thrust washers quite inexpensively, I presume Harry has them as well.

If your nylon thrust washer has failed or is worn its a good idea to take the transmission apart and replace the circlip before it fails.

Cheap insurance to save what is an expensive transaxle to rebuild.
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Old 11-03-2012, 11:28 AM   #17 (permalink)
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This thread has me so worked up, I am going to schedule with a mechanic to have this done despite the fact that I don't have one of these Esprits!


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Old 11-03-2012, 01:46 PM   #18 (permalink)
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Surprised Harry didnt mention this, the nylon trust washer that is on the clutch end of the imput shaft will eventually wear and or disintergrate either speeding up or actually causing the demise of the circlip.

There is a fellow in England who sells the Nylon Thrust washers quite inexpensively, I presume Harry has them as well.

If your nylon thrust washer has failed or is worn its a good idea to take the transmission apart and replace the circlip before it fails.

Cheap insurance to save what is an expensive transaxle to rebuild.
Hi,
sorry, didn't read the post carefully.
Imho, the nylon thrust washer wears out because failure of the circlip and not the other way round.
As I said before, most problems are with the Turbo version wich has no lip at all at the end of the splains. Springload is quit strong. Inputshaft is pushed towards the cranckshaft and that is to much for the nylon thrustwasher.

New circlip is drop in when you have the primairy shaft out on the bench.

with kind regarDSm,

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Old 11-03-2012, 01:54 PM   #19 (permalink)
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Thanks for the input Wayne, I thought it was the nylon thrust washer that was the 'culprit' behind this failure. At 71k my car shifts really smooth and I don't beat on it but then as brother Atwell's car just went out with no warning.

I stand corrected, Harry's post got in there whilst I was writing mine and saw what he had to say.
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Old 11-12-2012, 10:05 AM   #20 (permalink)
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Early Citroen transaxles used with the 907 and 912 don't typically suffer this failure. The input shaft had an abrupt shoulder for the circlip to bear against, and it seldom gets past that.

In anticipation of the Turbo's increased torque, a number of strength "improvements" were made to the transaxle, including blending out any sharp edges and transitions that might cause stress concentration points. In that effort, the circlip's shoulder became a taper which is far less secure. Eventually, the taper can work past the circlip, and then the spring forces the input shaft forward against the end of the crankshaft. Their hearts were in the right place, but in hindsight, this was a bad "improvement".

There's no warning that the circlip is about to fail, but the wheels don't come off the wagon all at once. There are signs that something is wrong before all drive is lost, but you need to be sensitive to notice them, and then quick to take action. Delay becomes progressively expensive to repair.

Initially, the Nylatron washer will take the thust load when the circlip fails and the input shaft pushes forward against the crankshaft. The washer is a relatively low friction surface, but still, there will be an increase in drag between the crank and input shafts, and some amount of torque will continue to be fed into the gearbox even when the clutch is fully released. The synchros can deal with any continuous torque input very well, and that will lead to your first clue something is wrong. Sensitive owners with a little mechanical empathy will notice that it suddenly becomes more difficult to shift gears... especially getting into 1st while at a standstill. That's the first symptom most folk ignore.

The Nylatron washer can't take that friction load forever, and eventually gets chewed up to dust (the Nylatron washer is a victim, not a culprit). Then the shoulder at the front end of the input shaft bears against the spigot bearing's end face, and the end of the crank. It's metal-to-metal contact, so the friction goes up, more torque is fed into the gearbox when the clutch is fully released, and shifting becomes even more difficult than it was initially. Folk complain about Red Hose Syndrome, bleed the hydraulics, and adjust the clutch, but they keep driving the car.

When the clutch spline reaches the end of the crank, it makes a very effective milling cutter, and starts boring into the back of the crank. That's when serious damage to the crank begins. And now the friction torque load fed into the gearbox really goes up, and shifting becomes very problematic. Also, there's the distinct sound of milling cast iron/ steel when the clutch pedal is depressed, sometimes accompanied by a squeal. But that often gets lost in the general caucauphony in the engine bay, and doesn't get noticed in the insulated cabin. Folk keep driving the car, and complaining about the shifting.

As the input shaft bores forward into the crank, the male spline at it's back end is slowly disengaging with the female spine in the primary shaft, inside the transaxle. Less and less tooth engagement is available to transmit the engine's full torque when driving, the splines begin to distort (shafts are now shot, must be replaced to fix), and eventually the spllines shear. When that happens, all drive is suddenly lost. Select any gear, let out the clutch, and there is no drive at all... just a loud, piercing squeal, like amplified finger nails on a chalk board.

That's when folk start to pay attention, but it's way too late. The loss of drive was sudden... instant, even... but getting there took some time AFTER the circlip failed. So, going back to the first premise in this thread... define "sudden".

*~*~*
Pro-actively replacing the thin wire circlip with a substantial snap ring can prevent the problem from ever occurring. Harry Martens and JAE both offer snap ring upgrades. The mating abutment in the shaft is still a taper instead of the earlier step, but the "real" snap ring won't let the input shaft get by.

Both suppliers can also provide you with a replacement input shaft with a step abutment. It's not necessary to replace a perfectly good input shaft, but if your original is screwed up and must be replaced anyway, then the stepped version is an additional option.

The input shaft disappears into the back wall of the bell housing, and runs in a tube/ tunnel through the differential area... a separate compartment within the transaxle, separate from the "gearbox". The compartment is split fore and aft, with the back half (output shaft centerline back) being part of the gearbox housing, and the forward half being part of the bell housing. Gaining access to the circlip requires removing the output shaft housings which straddle the joint line, then removing the bell housing. So, yes, you are partially opening up the transaxle and revealing the CWP & differential, but not the "gearbox" portion itself. It's not an insignificant effort, but it's minor compared to a complete disassembly/ rebuild.

Once you get in there, actually replacing the circlip with the larger snap ring is only a few minutes work... plus some general clean-up. Then put it all back together. Since disassembly to this point frees the differential assembly, there's now an opportunity to replace the support bearings, and check & adjust the bearing pre-load and the CWP backlash. But that's optional (Shipwright's Disease) and not required for installing the snap ring upgrade.

*~*~*
If the splines between the input and primary shafts have gotten to the point of distorting, or stripping, then both shafts must be replaced. The input is easy, and can be done when you do the snap ring upgrade. However, the primary shaft is inside the gearbox, and replacing it requires full disassembly.

The pinions for 1st & 2nd gears are integral parts of the primary shaft. Since gears are made in matched pairs (or at least wear-in to become matched pairs), and should never be mixed and matched, properly replacing the primary shaft requires that you also replace the mating gears for 1st & 2nd. So the ripple effect to input/primary spline failure is both a lot more work, and more parts expense. While you're in there, inspect all bearings, and take the opportunity to replace the brass synchro rings.

*~*~*
The damaged crankshaft can be repaired in two ways. Both involved boring the pocket for the spigot bearing (release bearing) oversize, so that's a trip to the crankshaft machine shop. Then either install an insert to restore the original bore diameter, and replace the original needle bearing. Or install a real ball bearing, similar to what Lotus used on the later engines mated to the Renault UN1 transaxles. A simialr bearing, but with a 15mm bore for the Citroen, instead of 17mm for the Renault.

Then, if the circlip/ snap ring should ever fail again, and the input shaft pushes forward against the crankshaft, the ball bearing is capable of supporting the thrust load without further damage. If you're going to repair a damaged crank, I can't imagine ever restoring it to the original needle bearing configuration, and passing on the chance to upgrade to a ball bearing. I've posted a Word.doc with all the details to the Files section of the Turboesprit mailing list on YahooGroups. You can download a copy there.

I strongly suggest that any Turbo Esprit-Citroen owner who is rebuilding the engine, or has the crank out for any reason, take the time to upgrade the spigot bearing to a ball bearing. The ball bearing is cheap (actually less expensive than the OEM needle bearing), and the machining cost is insignificant compared to the benefit.

Similarly, any time the transaxle is out of the car for any reason, I strongly recommend upgrading the circlip to a snap ring. The part is dirt cheap, and if you can do the work yourself, the greatest cost is some of your time.

Any of the upgrades, an input shaft with a step for the circlip, a HD Snap Ring, or a ball bearing spigot can solve the problem alone. There's nothing wrong with using all three together... belt-n-suspenders, plus a crotch strap. The input shaft's purchase price is the biggest hurdle, but the ball bearing and snap ring are minor investments that pay a big dividend. I prefer to do the spigot bearing and snap rings, and not worry about the input shaft unless something happens to force it's replacement.

If you recently had work done to replace the clutch, flywheel or rear main seal, then NO !!, it is NOT reasonable to assume the snap ring upgrade was done without you asking for it. This is a grassroots upgrade, and not something normally done by mainstream specialists/ dealers.

Regards,
Tim Engel
Lotus Owners Oftha North (LOON)

Last edited by Esprit2; 11-12-2012 at 10:13 AM.
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