2ltr 5 speed gearbox problem

[keith m 131]

Hi all,

I have a few problems associated with the gearbox,

1)  when reversing and with the clutch pedal released it sounds ok but if I depress the pedal and let the car free wheel the I can hear a loud rumbling grinding noise.

2)  With the engine on tick over and in neutral I can hear a whirring sort of noise which gets slightly louder if I rev the engine.

I had a new complete clutch assembly (original part) fitted only last year , 3.500 miles ago.

3)  I also have a vibration and loud droning noise from 40 mph upwards.

Do you think that the input shaft could be shot and causing all the problems and could the spigot bearing at the back of the crank in the flywheel also be a cause.

Can the spigot bearing be replaced without removing the crank from the block.?


I am planning on removing the gearbox in the next few days but what else should I look for and what sort of damage inspections should I carry out.

Fresh 15/40 oil in the box when new clutch was fitted.

A long post I know but all input would be really appreciated.

Regards

Keith

[mirafioriman]

Not sure about the fault diagnisis but you should be able to change the spigot bearing without removing the crank.

[Tas131]

1)  when reversing and with the clutch pedal released it sounds ok but if I depress the pedal and let the car free wheel the I can hear a loud rumbling grinding noise.

Sounds like a reverse gear problem. I had the opposite, noisy under load, quiet with clutch in.

2)  With the engine on tick over and in neutral I can hear a whirring sort of noise which gets slightly louder if I rev the engine.

Input shaft bearing. Mine's done it for years, not an issue.

3)  I also have a vibration and loud droning noise from 40 mph upwards.

Sounds like a tailshaft, uni or centre bearing issue.

Do you think that the input shaft could be shot and causing all the problems and could the spigot bearing at the back of the crank in the flywheel also be a cause.
Can the spigot bearing be replaced without removing the crank from the block.?

The spigot bearing only turns around the input shaft when the engine is running and the clutch pedal is depressed. With the clutch out, the input shaft is effectively locked to the crank.

I'd be having a good look at the tailshaft before I pulled the box out.

[keith m 131]

Thanks David and Mick for your reply.

I should have said in my post that I had everything associated with the prop shaft replaced and balanced. The rubber guido, UV joints, centre bearing. So I can safely rule out that possibility.

With regards to the noise and vibration , if the gearbox front and / or rear brearings are shot then would that allow the shaft to spin out of balance hence the possibility of vibration and noise running through the drivetrain?

I have looked at the Haynes manual and although it is very informative, it does not explain how to inspect or test the gearbox for damage etc.
If there is a problem is it fairly obvious when inspected. I dont want to rush in by taking it all apart and then find out from a member that there are certain procedures or process of elimination that should be followed.

Am I showing the gearbox too much respect? and should I just open it up and see what is going on. Are they really that difficult to understand.?

Please keep it coming.

Regards

Keith

[djape1977]

you could be dealing with more than one problem at the time.

don't exclude propshaft problems. the fact that it has been rebuilt doesn't mean that it's ok. i've seen U-joints that failed after couple hundred kms more than once. rubber donut, propshaft mount too. plenty chinese sh*** out there. parts that look ok but are made out of chewing gum rubber.

you say there's a noise coming from gearox when running on idle and clutch pedal is not depressed? what happens when you press the clutch? does the noise dissapear or change? if it does, than the input bearing is shot. that is usually not an immediate problem if you can live with the noise, but it doeas get worse over time. i guess that in the end it could lead to all sorts of noises and vibrations if you persisted in driving it long enough without repair.

also, there's a possibility that clutch plate is beginning to desintegrate and it can make all sorts of noises and vibrations. again, chinese sh**

how complicated is the gearbox? well let's put it this way... if you can rebuild the engine, than it's safe to assume you can rebuild the gearbox too. but most mechanics that rebuild engines wouldn't touch a gearbox with a 10ft pole.
there's some things inside that will leave inexperienced scratching their head after banging at it with a big hammer for hours, and all it took was little heat or counter screwing nut. still, biggest issue is availability of the spare parts. even exit shaft oil seal is next to impossible to find these days. proper quality bearings are the tale to tell!

all in all, take a good look at the propshaft, you may use a little force to see if anything is moving where it shouldn't. if everything seems ok, gearbox must come off. presuming the clutch plate and pressue plate are ok, easyest way to test the gearbox is to take input shaft and jerk it up/down. if it moves at all, bearing is shot. at least input one, and you have a reason to disassemble the gearbox.

next logical question - how 'bout  a used gearbox?

well, as we in the balkans say, it's a cat in a sack. you don't know what colour it is or if it will catch mice untill you buy it, bring it home and let it out of the sack. you could get lucky and buy a good gearbox but more likely you'll get another one with same problems. they're all 30 years old you know. i either buy gearboxes for 10e and hope i can use anything from it or i test drive the car, and if gerbox is fine i take it out and pay 150e. any gearbox that's been standing in a shed for past 15 years and owner claims that it's in "perfect condition" is most likely just a piece of junk worth 10e.
if you can find someone that can guarantee your money back + expense of transport and instalation if gearbox is not ok, than buy it.
gearbox from a low mileage but rotten 131, 132 or argenta? hmmm... well, oil seals will desintegrate after couple hundred kms and you'll be pouring in oil every week. everything else might even be ok.

by the way, what would be the cost of full gearbox rebuild in UK?

[Tas131]

That oil's a bit light too, isn't a 20W-50 equivalent specified?

[djape1977]

it's just fine in UK climate. for southern europe 20-50 would be the choice and even 20/60 for north africa, middle east, australia...

[keith m 131]

Thanks again for the response.

I have seen that Bayless in US have the majority of aal the parts required with the exception of the output shaft seal and the input bearing, sods law that isn't it. The output shaft seal is not leaking so I suppose that is something. I do however have some oil leaking down at the bottom of the bell housing so that might be a tell tale as to the input shaft bearing being shot.

When I depress the clutch pedal the noise goes away.

When I put it in neutral an rev the engine to about 3000 revs I can feel a lot of vibration up throught the floor and can hear what I can only describe as the sound of a loose metal bracket making a rattling noise. I cant see where that is coming from so could it be something to do with nthe input shaft bearing or the reverse gear as I mentioned earlier.

What I am planning on doing is to remove the gearbox and refit the bell housing and starter and run the engine to rule out any issue with a crank balancing issue.

With regards to the prop shaft well I still get exactly the same vibration when just sitting in the stationary car, so surely that would rule out the prop.

I cannot live with this vibration so need to do someting to sort it.
any ideas where I could get a input shaft bearing because I would like to try and sort this box obviously with in reason rather than buy someone elses s---

Is checking the input shaft for movement the only thing I can chect to try and assertain what is wrong. Would the reverse gear noise be an issue for vibration or just an annoying noise.

Regards

Keith

[djape1977]

you're welcome Keith.

than it's the gearbox, 99% sure. if there was a problem with engine, you'd know, believe me!

you could try to turn the gearbox input shaft by hand in diferent gears, that would give you some idea if noises and vibrations are coming from gearbox. even better, i have fabricated adaptor from old clutch plate heart to connect gearbox to electric motor, or a hand held drill to be more precise, 1000watts one, to turn gearbox and see what happens. anything other than completely smooth motion is a sign of shot bearings. prolonged driving with shot bearings leads to teeth on gears getting worn and gearbox housing getting damaged, and from what you describe this might be the case with your gearbox. if everything inside is more or less damaged, you're better off getting another gearbox. replacement parts might cost a lot. damage on gears and sinchros, even small wear, will result in noisy gearbox even with new bearings installed. also, input shaft bearing needs to be adequate "class" of quality, not just right dimensions in order to work well longer than couple thousands kms.

and about that pesky tailshaft oil seal... well it's standard dimension in US, but people almost never cross reference catalogues.

[keith m 131]

Djape,

Again much appreciated. You are a head of knowledge, I bet you have been involved with these engines etc for a long time.

The idea of using the centre of the clutch plate fitted to a drill is clever, now I just need to work out how I am going to do something similar.

You make good sense with regards to getting a replacement gearbox and that maybe the end result but you have given me a good starting point to test for damage.

Your idea of using a drill to spin over the input shaft will also be extremely helpful in testing a replacement gearbox for smoothness before I buy it. Is there any sort of general wear and tear noise that would be acceptable in a replacement gearbox.?

I will keep you posted of my progress.

Regards

Keith

[djape1977]

. Is there any sort of general wear and tear noise that would be acceptable in a replacement gearbox.?

none