DS20 gearbox
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Thread: DS20 gearbox

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    Fellow Frogger! badabec's Avatar
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    Default DS20 gearbox

    Hello, I've just separated the engine and BVM gearbox. The gearbox input shaft (the one splined to the clutch) has come out of the gearbox. I can't see any detent or circlip groove so is this normal? I can push it back in against a spring.
    The other cause for concern is the state of the splines where it enters the gearbox, they look quite worn.
    Any thing major wrong or par for the course?
    Thanks
    Peter

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    Fellow Frogger! citroenthusiast's Avatar
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    There is supposed to be a circlip in a groove that is undercut on the inside of the transmission input shaft (the part that is still in the transmission). It should engage the splines to keep that part of the shaft from coming out.

    Yes, badly worn splines on the input shaft are a concern.
    Cheers,
    John T.

    54 TAV Legere; 61DS19 LHM BVH (son's); 71DS21 BVH; 73SM 3.0; 73SM EFI (Megasquirt); 73SM 3.0 (other son's)

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    Hi Peter,
    On top of what John has said.
    Most of the reason for the wear is Citroen did not lubricate the spline at the factory - they were dry assembled.
    Wear in these splines contributes to a lot of drive line play, and when they fail it's a big repair.
    The circlip has disintegrated for that reason.
    The only way to deal with it is to strip the gearbox and replace both the input shaft and the spigot shaft to the clutch.
    Given there are a plethora of 4 speed manual boxes around it would likely be cheaper to replace the whole gearbox with one with a good input and spigot shaft. Best done now while it's out.
    Cheers,
    Mark...
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    Quote Originally Posted by ds21bvh View Post
    Hi Peter,
    On top of what John has said.
    Most of the reason for the wear is Citroen did not lubricate the spline at the factory - they were dry assembled.
    Wear in these splines contributes to a lot of drive line play, and when they fail it's a big repair.
    The circlip has disintegrated for that reason.
    The only way to deal with it is to strip the gearbox and replace both the input shaft and the spigot shaft to the clutch.
    Given there are a plethora of 4 speed manual boxes around it would likely be cheaper to replace the whole gearbox with one with a good input and spigot shaft. Best done now while it's out.
    Cheers,
    Mark...
    Beware of what you might be getting if just doing a gearbox swap. There are different versions of the short stroke gearbox with differing gearbox and final drive ratios. Being a DS 20 it may well have different ratios to a DS23 for example.
    You may end up with a car that is more "long legged" than you are used to and while that may suit your usage, it may not. The small 1985cc engine is not as torque laden as a 21 or a 23. No doubt someone will contribute a more exacting version of my thought.

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    UFO
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    Here you go - all the 'box ratios for you to decode. Hours of fun for the whole family!

    CitroŽn DS/ID and XM Web-Site

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    Hi Peter
    If you are thinking of either a swap or rebuild then, putting aside gear ratio issues for a moment, Richard Burch was selling a five speed manual gearbox at Little Horwood last week. It didn't sell (as I helped him load it back in his 'H' van). He lives nearby - so it's located in that part of the world.

    Paul
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    1000+ Posts forumnoreason's Avatar
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    go the 5 speed!

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    Quote Originally Posted by UFO View Post
    Here you go - all the 'box ratios for you to decode. Hours of fun for the whole family!

    CitroŽn DS/ID and XM Web-Site
    There !!!!!!!!!!! I knew it would happen.

    back in period my DS20 ( 1969 Euro delivery with charcoal dash and rectangular switchgear ... on red tourist plates ) had a particularly annoying on/off whine in the 4th ratio. It was cured by replacement of a couple of gears. So even within the same model designation there may well be differences of gear sets and ratios.
    Having had all 3 engine sizes the 21 was the sweetest. The 1985 was nowhere near as smooth as a carb 21 and the 23 with injection could be downright gruff.

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    Quote Originally Posted by fritzelhund View Post
    Having had all 3 engine sizes the 21 was the sweetest. The 1985 was nowhere near as smooth as a carb 21 and the 23 with injection could be downright gruff.
    The engine on my 72 D Super Five was a very sweet unit But then again so was the engine on my DS23 IE Pallas. Maybe all engines were not created equal? Sometimes two otherwise identical units can run quite differently!
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    Cheers Gerry

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    Quote Originally Posted by gerrypro View Post
    The engine on my 72 D Super Five was a very sweet unit But then again so was the engine on my DS23 IE Pallas. Maybe all engines were not created equal? Sometimes two otherwise identical units can run quite differently!
    My DS20 was a plain DS, not a Pallas so it missed out on the extra sound and heat shield around the firewall. The DS21 was a Pallas, so therefore smoother to travel behind. The Pallas 23 injection could generate quite a snarl and was naturally gruntier. Jaguar drivers complained of the newer alloy 6 cylinder engine as being "shrill" after the old traditional iron lump. I thought the carb 21 was the nicest to travel behind. A perception issue perhaps.

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    Hello, oh well, it's a shame. I have only driven the DS20 ambulance about 20 miles and it had a lovely gearchange and no whine.
    I looked at that 5 speed box but mine is a left hooker and I don't want to mess about changing the linkage or fabricating clutch cable mountings. Thanks though.
    On the bright side, I now have a perfect clutch alignment tool!

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    Fellow Frogger! badabec's Avatar
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    It will soon be a 21, new pistons and liners are on their way...

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    wish I had a 5 speed box, I put 21 pistons in. Then it would be a DSuper!

    I always thought the motor ( before) was hankering for an extra gear when cruising up around 100km/h and the extra gearing would allow it to labour less at speed.
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    Hello, what is the purpose of the circlip? Is it just to stop the shaft falling out in storage? The shaft can't go anywhere once the box and block are bolted together.
    Peter

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    Hi Peter,
    Just as you say - to stop it falling out when the transmission is separated from the engine.
    Cheers,
    Mark...

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    Quote Originally Posted by forumnoreason View Post
    wish I had a 5 speed box, I put 21 pistons in. Then it would be a DSuper!

    I always thought the motor ( before) was hankering for an extra gear when cruising up around 100km/h and the extra gearing would allow it to labour less at speed.
    Actually it would "be" a D Super 5.

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    Yep. With a five speed box alone it would (still?) be a D Special - albeit with the optional fifth gear. Add 21 pistons and you've made yourself a DSuper5.
    1968 DS21bvh Pallas in Gris Palladium

    Restoration blog: https://ds-restoration.blogspot.co.uk

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    Hello, next question. I took the top off the gearbox to check the internals. I used petrol and then panel wipe to give it a good clean. Rotating the internals using the drive flanges, I could hear a metallic tinkling. Took off the front cover to expose the bearing and found the outer race only had 10 balls in it. The tinkling was the sound of the balls falling around the track.
    Only 10 balls in the outer race, is that correct?

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    From memory, there should be a plastic ball separator in that bearing. Has that gone completely missing?
    Cheers,
    John T.

    54 TAV Legere; 61DS19 LHM BVH (son's); 71DS21 BVH; 73SM 3.0; 73SM EFI (Megasquirt); 73SM 3.0 (other son's)

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    Hello, yes, the rear race has a plastic ball separator, it is completely missing on the front race



    Does the gearbox have to come apart to remove that bearing? Or can it be pulled from the outside?

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    Fellow Frogger! citroenthusiast's Avatar
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    It can be removed from the outside - that is one of the first disassembly steps. However, the position of that bearing is what determines your pinion depth, so if anything moves, your pinion depth will be off. Up to you if you want to risk it. Otherwise, I would take a pinion depth measurement before you disturb anything, so you are sure to get it back in the same position. If you replace the bearing (as opposed to reconditioning it with a new spacer), you will almost certainly have to replace a pinion spacer shim (which means total tear down to get the pinion shaft out).

    That speedo drive gear requires a lot of torque to remove. To keep the gearbox from moving, I fashioned a lever from a 5' long piece of galvanized water pipe and drilled some holes so I could fasten the pipe to the top of the gearbox (M7 bolts - gearbox cover removed).
    Cheers,
    John T.

    54 TAV Legere; 61DS19 LHM BVH (son's); 71DS21 BVH; 73SM 3.0; 73SM EFI (Megasquirt); 73SM 3.0 (other son's)

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    Quote Originally Posted by citroenthusiast View Post
    It can be removed from the outside - that is one of the first disassembly steps. However, the position of that bearing is what determines your pinion depth, so if anything moves, your pinion depth will be off. Up to you if you want to risk it. Otherwise, I would take a pinion depth measurement before you disturb anything, so you are sure to get it back in the same position. If you replace the bearing (as opposed to reconditioning it with a new spacer), you will almost certainly have to replace a pinion spacer shim (which means total tear down to get the pinion shaft out).

    That speedo drive gear requires a lot of torque to remove. To keep the gearbox from moving, I fashioned a lever from a 5' long piece of galvanized water pipe and drilled some holes so I could fasten the pipe to the top of the gearbox (M7 bolts - gearbox cover removed).
    Hi, take a wrench 36 mm, grind it down to 5 mm thickness, and put gearbox in 2 gears at the same time, than you can loosen the speedo nut.

    I have new input shaft for DS in stock.

    cheers,

    Harry Martens

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    Hello, thank you to everyone. Today I milled down a 36mm spanner, just around the opening, so it now fits. Next stage is to modify a ball joint socket so it can slip on sideways then weld the spanner head to the socket. Then I can use a torque wrench to tighten it properly. I can't see a way of getting the torque correct by using a spanner.

    Is there an interlock in other housing (not the reverse gear housing)? Or am I just being too delicate trying to engage two gears?

    Thanks

    Peter
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    Lock the gears by removing one of the grub screws (e.g. 3-4 synchro). This will allow you to engage the synchro without moving the selector shaft (which will engage the lockout on the remaining shafts). Then move one of the other sychros to engage (e.g. reverse) to lock the transmission
    Last edited by citroenthusiast; 28th June 2018 at 10:28 AM.
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    Cheers,
    John T.

    54 TAV Legere; 61DS19 LHM BVH (son's); 71DS21 BVH; 73SM 3.0; 73SM EFI (Megasquirt); 73SM 3.0 (other son's)

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    Quote Originally Posted by ds21bvh View Post
    Hi Peter,
    Just as you say - to stop it falling out when the transmission is separated from the engine.
    Cheers,
    Mark...
    I'm refitting my clutch and need an alignment tool. As peter says, a spigot shaft is ideal. A rather optimistic question:

    I have a spare gearbox I can use bits from: will the spigot shaft disengage from the circle and the input shaft if I give it a sharp tug? In other words is the circlip just acting as a locking or locating ring? If so, can the spigot shaft be shoved back into it's correct place afetr removal?

    Alternatively, would i need to dive into the box to remove the circlip?
    1968 DS21bvh Pallas in Gris Palladium

    Restoration blog: https://ds-restoration.blogspot.co.uk

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