D's with a significant whine in 4th
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  1. #1
    Fellow Frogger!
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    Default D's with a significant whine in 4th

    Now Peter, from the mountains near Maleny, Qld.
    It's about time you got into that D Special of yours and yes, it does seem that it's the obvious car to take to Perth.
    Cover those old bomb tractions and tie the 2CV to a tree so it doesn't get blown away and get into a real car for a while. You asked last Sunday about that bloody whine and although I think Citroen made the perfect car there is the odd, tiny, tiny annoyance that might have been worked out better to stop us dedicated drivers going completely round the twist. And so we come to the top gear whine. This did come up on one of the DS sights a while back so I thought that I'd reprint it.
    Now, Buttercup Bob is a bit of a whizz kid and I don't think he'll mind if I include his explanation plus there is the odd other comment. By now Bob might be using banana skins but that was then.
    Others said to keep GOOD oil in the box and some put additives.
    IT IS A PAIN so I thought it was worth bringing up. An earlier '68 DS21 I had some years ago was the worst for this. Hang in there Peter as someone might help us out.
    As someone said the other day --- turn the radio up a bit louder.

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    A dedicated D driver who has gone a bit gaa gaa from whining-- gilberthenry

    ----------------
    From: "Buttercup Bob" <[email protected]> Date: Thu Mar 4, 2004 8:42 pmSubject: 4th gear whine...

    Over the years I've heard about and noticed quite a few later Deeswith a significant whine in 4th.Whenever I asked trained Dee mechanics about it, they always said itwas "just one of those things and nothing can be done about it".There are 2 C35s in Aus, and last year when I met the famous JimReddiex, I mentioned that I had one of the 35s (that he imported in1979. He asked if I got the quiet one or he noisy one.... apparentlyit was noisy from new.I got the noisy one... In top (4th) it really howls with load on,while its quiet on overrun. It has a Dee type 4 speed box, with arotor for the parking brake on the extended lower shaft, andreducing/reversing final drive gears where the brake rotors are on aDee. The C35 has outboard brakes.I've been doing some major work on it and decided to have a look inthe box while I had it all out of the vehicle.I found that the bearing that supports the 4th pinion on the topshaft was very sloppy (in a Dee this is a caged needle rollersleeve, while its bronze faced steel bush in the C35).The pinion was able to slop around way too much, causing the teethto mesh at a bad angle, and also the pinion end face was wearinginto the face of the main top shaft bearing.I suspect that the design is a little deficient, in that there isnot a significant thrust area to take the endthrust of the helical4th pinion. Any excess clearance in the 4th pinion needle bearingallows the pinion to tilt away from the contact with the lowerpinion. All the other gears have very big surfaces to take theendthrust and the tendancy to tilt away from the load.I'd suggest that Dees with noisy 4th gear are those with excessclearance of this bearing.After a lot of parts juggling between the C35 box and 2 spare Deeboxes, I've now got it sorted out by replacing the top shaft (theC35 one was worn by the slopping pinion) and replacing the 1st & 2ndlower pinions ('cos the Dees have a slightly lower 2nd ratio). Nowthe 4th pinion is carried on a needle cage.It'll go back in over the next couple of days, then I'll be able toreport on the success or otherwise of the noise reduction.I wonder when Citroen started using bronze bushes instead of needlecages under the pinions ?? Did very late Dees have this, or is itjust a C35 thing.I reckon that the design really needs a thrust washer of significantdiameter between the 4th pinion and the main bearing inner race.it wouldn't be very difficult to modify the existing parts to allowthis........Any comments................ Harry ??Bob >>
    With my "musicians" hearing I can barely detect whine anymore (unless it isreally significant). But when my wife hears it I usually find the tranny oillevel is "down a bit". Also adding an additive (I use a colloidal graphite)makes the bearing a bit happierStan GeorgePortland OregonHe filled it up and added a product called "Slick 50" and it has made atremendous difference. BillI use Lucas oil additive in my gearbox, almost 100%. Quiet as a churchmouse.
    DG
    The bronze bushes are only used into the C35. Very poor constrution.I allways change it into needle cage.The main problem is that the bearings ( especially the frontprimairy ) get almost no oil, even if the level is ok.I can strongly recomment Redline MTL transmissionoil.Reduces noises and improves shifting.harryHi Deeviates,I've had this vehicle since 16,000 km, it whined then, it whinedmore recently. I've tried thicker oil, I've tried Nulon additive,I've adjusted the diff pinion distance both ways.............On pulling it apart the ONLY apparent wear or damage is to the 4thpinion & its bearing. Every other part is perfect.Over the last few days I've pondered the design, the wear, thesymptoms.......... I'm convinced it was caused by excess pinionclearance both radially & axially. Once this situation arises (fromnew assembly or from excess wear from low oil) there is no way thatany oil additive can correct the mis allignment of the pinions, orthe wearing of the thrust face. The pinion sits against the mainbearing inner race with a contact ring of only 2.5 mm radial width!All the other gears have thrust contact area MUCH greater thanthis....... and we only use them for short periods. City vehiclesmight travel in 4th for only 40% of their life. My vehicles spend95% of the time in 4th.This is a design fault! I'm absolutely convinced. Its a shame, asthese are otherwise very good gearboxes, and a fix could have beenvery easy to create. I've designed a fix that requires just 1 simplepart (a thrust washer) and the adjustment of an axial dimension ofthe top shaft and 4th pinion.I'll let you know how it goes....BobHi Carter,I can think of 2 possible sources of whine in 3rd during overrun.1. During drive the top pinion is thrust forward. In the case 3rdgear, the pinion rests against the large face of the flange thatcarries the selector ring & synchros. This large face holds thepinion squarely in place against the thrust.During overrun, the pinion is thrust rearward, where it only has asmall face of the 2 piece split ring that locks the assembly. If theneedle bearing supporting the pinion has excess clearance, it willallow the pinion to tilt....... causing noisy mis-allignment of themeshing teeth.This is exactly the same as the whine in 4th when power is on, 'cos3rd and 4th are facing each other symmetrically either side of theselector flange.2. During drive the lower pinions are thrust rearward, thus tendingto balance the forward thrust of the bevel pinion (against thecrownwheel). Thus thrust load on the main front bearing is low.During overrun the lower pinions are thrust forward adding to theforward thrust of the bevel pinion (this gets a bit complicaedbecause the helical bevel shape tends to balance itself duringoverrun, ie helical thrust rearward tends to balance conical thrustforward). I think that during overrun the load on the lower frontmain bearing is greater........ maybe if its less than perfect itthen gets noisy.However I would expect this to give noise during overrun in allforward gears.I'd suspect the first possibility.......... ie the needle bearingunder the 3rd pinion is worn.Bob

  2. #2
    1000+ Posts George 1/8th's Avatar
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    [QUOTE=gilberthenry]Now Peter, from the mountains near Maleny, Qld.
    It's about time you got into that D Special of yours and yes, it does seem that it's the obvious car to take to Perth.
    Cover those old bomb tractions and tie the 2CV to a tree so it doesn't get blown away and get into a real car for a while. You asked last Sunday about that bloody whine and although I think Citroen made the perfect car there is the odd, tiny, tiny annoyance that might have been worked out better to stop us dedicated drivers going completely round the twist. And so we come to the top gear whine. This did come up on one of the DS sights a while back so I thought that I'd reprint it.
    Now, Buttercup Bob is a bit of a whizz kid and I don't think he'll mind if I include his explanation plus there is the odd other comment. By now Bob might be using banana skins but that was then.
    Others said to keep GOOD oil in the box and some put additives.
    IT IS A PAIN so I thought it was worth bringing up. An earlier '68 DS21 I had some years ago was the worst for this. Hang in there Peter as someone might help us out.
    As someone said the other day --- turn the radio up a bit louder.

    A dedicated D driver who has gone a bit gaa gaa from whining-- gilberthenry

    ----------------
    Hey guys...this sounds to me like a diff type of thing. Sure it's front wheel drive but it still has a diff set up in there. That bronze bush thing cannot be as good as a needle bearing, and anything less is just bad engineering.
    I'd be looking for worn thrust bearings or similar in any old D with whining in 4th. It's not likely to be the 4th gear , more likely to be the pinion somewhere in the diff area.
    Good luck.
    Cheers...George 1/8th. (ex Ds21 owner ...with no whining that I could remember..)

  3. #3
    Real cars have hydraulics DoubleChevron's Avatar
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    Hi Guys,

    there is no doubt buttercup bob is a 'DS' genious, however before whipping the gearbox out I'd suggest you dump some Nulon G70 into the gearbox. It's made a dramatic difference to every car I've added it to, it certainly helped the diff whine in my '63 ID19, made a mind boggling difference (read MASSIVE) difference to my GS with regards to gearbox noise, it's synchro action improved dramatically as well.

    good luck !
    Shane L.
    'Cit' homepage:
    Citroen Workshop
    Proper cars--
    '85 Series II CX2500 GTi Turbo I
    '63 ID19 http://www.aussiefrogs.com/forum/citro%EBn-forum/90325-best-project-car-you-have-ever-seen.html
    '72 DS21 ie 5spd pallas (last looked at ... about 15years ago)
    '78 GS1220 pallas
    '92 Range Rover Classic ... 5spd manual.

    Yay ... No Slugomatics


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