Gearbox

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sleepy0905
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Gearbox

Post by sleepy0905 » Sat Jan 14, 2006 10:11 am

Right here is a good one i am after some sugestions on quietening my gearbox down it sounds noisy and ratly but as soon as you press the clutch down the ratly box is quiet so what is the best oil grade to put in it ,its a manual 5 speed and any additives such as molyslip or something.
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Post by Vanny » Sat Jan 14, 2006 10:39 am

would a new thrust bearing not be the solution?

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Post by cavmad » Sat Jan 14, 2006 10:55 am

Vanny wrote:would a new thrust bearing not be the solution?
Just what I was thinking and also probably worth renewing the clutch while you`re there. I think Ken knows the best/most cost effective ones to get. Without wishing you to spend money you may not be able to afford why not go the whole hog while you`re doing it and replace octopus at the same time? At least you know the car will be sound for a long time then and it may save you having to take everything apart again a couple of months down the line if the clutch and octopus fail on you.
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Post by jeremy » Sat Jan 14, 2006 11:16 am

Rattly clutch bearings seem to go on for a while - in my case 6 years and 38,000 miles and it doesn't seem to be getting any worse. One day it will all have to come out and then I'll deal with it.

In fact you begin to wonder how long a new one would stay quiet for as it had obviously been like that for some time!

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Post by sleepy0905 » Sat Jan 14, 2006 11:27 am

Its the box itself the clutch, release arm and thrust bearing + the ball spigot have only been done a short time as the old clutch failed completely and i had to change the box because the old one failed internally.
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Post by cavmad » Sat Jan 14, 2006 11:32 am

This really will sound like another sales pitch BUT.... guess what I have (still attached to engine, still attached to car) :?:
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gearbox

Post by Toddman » Sat Jan 14, 2006 11:41 am

If the gearbox rattles at rest with the clutch released then quite often it is the gearbox idler bearing.
The early XY engines with the gearbox underneath suffered from it terribly, a common bodge was to increase the idle speed a touch to help with the rattle.
I am not a gearbox expert but that would be my semi educated guess :D

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Post by sleepy0905 » Sat Jan 14, 2006 11:43 am

thanks luke thats a good sugestion
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Post by jeremy » Sat Jan 14, 2006 11:48 am

The general experience seems to be - put the wrong (or a thicker) oil in the gearbox and you won't be able to change gear.

AlanS swears BY Slick for gearboxes and AT it for engines. May gum up the bearings a bit which is what you want but what additional sliperyness does for the synchro I don't know.

As an observation the gearboxrx seem evry tough and reliable as there's no history of bearing failures on these boards.

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Post by DavidRutherford » Sat Jan 14, 2006 11:59 am

Many years ago I had a Talbot Horizon 1.9D with BE1/5 gearbox that had a really nasty bearing hiss/rattle when the engine was idling. It went on for ages until I deceded to do something about it.

The odd thing is that the BE1/5 in the Horizon had an oil spec of 15W-40 engine oil, whereas BE's fitted to other vehicles need Total 75W-80W. I tried a box full of Total, and that made bugger all difference. Figuring I had nothing to loose (as I had a spare box available) I tried a 50/50 mix of 75W-80 GL4 and EP80W-90. This worked wonders. The gearbox was instantly quiet, and although the "cold" gearchange was a little stiffer (you had to give it a touch longer for the synchros to do their stuff) the "hot" gearchange was much smoother.

I ran with that mix for something like 60k miles with no problems at all. The rest of the car rusted away before anything else could fail!
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Post by sleepy0905 » Sat Jan 14, 2006 11:59 am

Well i will change that then about 6 months after we got this car it threw its main bearing and destroyed the clutch and the gearbox casing which had a hole you could put a fist through the garage we gott it from changed the box and clutch but the box they fitted was of a petrol engine model and it had to be changed again about 2 years later for the correct one of a diesel but that was changed recently after it dumped a couple of syncro meshes and changing gear became a fun double de cluch method.
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Post by AlanS » Sat Jan 14, 2006 11:06 pm

I'll throw 2 bobs worth in here FWIW (Whoever thought of 24 hour days should be shot; I need at least 36 to just do what's outstanding without trying to catch up on what's been left behind) :oops: :oops: :roll:

I recently responded to a similar posting over here and was promptly howled down by a casual poster with several strange hang ups who was left red faced when the owner discovered this can actually be the cause.

Before you do anything, check the oil level in the gearbox. These things seem to have the knack of getting allowed to run dry as I discovered on 3 of my own cars when I first bought them and they will get these strange noises that disappear when the clutch is depressed and/or even if you sit your hand on top of the gear knob in certain gears.

The best formula I have found over several cars (BXs and a 94 Xantia) is to use a Castrol VMX 80 gear oil.
It's an API - GL4 rated oil and apparently later oils are GL5 which according to Gabor and Anders work better on later boxes due to the metal structure used in the synchros and exlains why they have problems with gearshifts when used in BX boxes.

Here's the data sheet on the VMX80 - http://www.castrol.com/liveassets/bp_in ... VMX_80.pdf

AS you will see, Castrol recommend the same rating oil but in the GL5 and this is where a lot of problems start.
If the problem were to be found to be a lack of oil, then when it's drained & refilled, use the VMX80 but with 125mls of Nulon G70 added to the first litre.
Slick may be OK, I have never used it and so can't comment on the similarities, but Nulon is cheap and according to some of the long time Pug owners out here, works as well as the dearest of gearbox additives.
If this mix is used, then to get the maximum benefit from it, use it for 5 - 8000klms and then do another gearbox oil change, refilling with the same mix.
Everyone who has ever tried this makes the same comment; the gear oil comes out as black as tar as it seems to flush all the crap out of the nooks and crannies. Once refilled with the fresh stuff, I'll guarantee, you've never felt a BX gearbox change like it. It's smooth as silk and if there are any noises in the box, I found on a couple of ours, the noise has gone within about 2 klms.

Hope that's some help.



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Post by sleepy0905 » Sun Jan 15, 2006 11:44 am

clear as mud thankyou :roll: :wink:
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Post by Stewart (oily!) » Sun Jan 15, 2006 3:18 pm

Nulon doesnt appear to be available in the UK, slick 50 is probably as close as we will get over here, I have used molyslip to good effect in transmissions and engines before now, older honda ohc engines were reputed to take fifteen seconds to get oil up to their camshafts, moly made them last, in my old BeeMer the gearshift was renowed for having a crunchy shift, moly cured that totally too. I would agree to check the gearbox oil first though, it can disappear.
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Post by sleepy0905 » Sun Jan 15, 2006 3:27 pm

thanks i will look at slick 50 that sounds an idea to try i have just bought a litre of comma EP 75-80 gear oil and am going to check the level probably tomorrow.
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