General Gearbox problem

[lance1]

Hi, I have been through most of the forum looking for the symptoms that my gearbox is showing but cannot find anything. The other night the car developed a very load violent bang from which seemed to be the front driverside whilst on lock. I jacked up the left side of the vehicle today, span the wheel and found that it seems to lock up in both directions, but will free up if you move the wheel back from the locking up, it spins fine again until it locks . I thought it was the cv joint as I can hear metalic noises and feel vibrations on the driveshaft when being rotated. So I checked the right side and it does the same apart fron the driveshaft noise. It does the same with wheels straight or on lock when jacked up.

Do you think that the gearbox, diff is shot?

many thanks nate

 

[DaveMcT]

Most likely debris in the diff has locked the planet gears and they've have gone bang. There is potentailly a lot of force in there. If you welded the diff (apart from impossible steering) the half shaft would get twisted.

Usually debris gets thrown out of the casing and you roll to a stop with no drive.

A broken input bearing apart from leaking oil onto the clutch can drop debris into the gearbox and logic says the diff casing is a likely resting place.

The other option is a blown CV joint. Either way the driveshafts have to come out so you will find out sooner or later which it is.

 

[lance1]

Ok thanks for that. Its a very violent bang when it happens. The whole engine rocks! Well I have never done a gearbox before but I am going to have a go. It looks like drive shafts out disconect bits and bobs, support engine and undo any bolt until it comes out! Maybe a bit of a simplified view, but I always have this place if I get stuck

Now to find a new Box or is it viable to take it to a gearbox specialist?

thanks nate

 

[DaveMcT]

The box will be toast.

Get a suitable used gearbox and a new clutch. A good small garage will charge £120 to fit it.

On the "new" box always, check the gearbox input shaft bearing. There should be no sideways play at all. Any play means its on the way out and probably already dropped bits into the gearbox.

I have a totally unproven theory that UK's LH road camber is part of the problem...
Car parked on the street, oil collects are the LH end of gearbox leaving input bearing dry. Engine starts while bearing is still dry. Car movement eventually splashes oil up to that side but not immediately. This leads to premature bearing failure.
In the EU (except for Eire) cars lean the other way when parked so that bearing is nice and oily when engine starts.

 

[lance1]

Ok if its toast then I am going to do it. I want to learn more and do more with cars. I have just bought and begun studying the Hilliers fundamental motor vehicle book 1, learning loads. I think the puntos are a good car to work on, perfect for a beginner.

Interesting theory about the input bearing wear, I suppose its only a bearing that really does need lubricating on start up, the most vulnerable wear time. After years of dry start ups the bearing dies.

thanks nate.

 

[flying clutchman]

The box will be toast.

Get a suitable used gearbox and a new clutch. A good small garage will charge £120 to fit it.

On the "new" box always, check the gearbox input shaft bearing. There should be no sideways play at all. Any play means its on the way out and probably already dropped bits into the gearbox.

I have a totally unproven theory that UK's LH road camber is part of the problem...
Car parked on the street, oil collects are the LH end of gearbox leaving input bearing dry. Engine starts while bearing is still dry. Car movement eventually splashes oil up to that side but not immediately. This leads to premature bearing failure.
In the EU (except for Eire) cars lean the other way when parked so that bearing is nice and oily when engine starts.

Love the bearing theory! Unfortunately The only cars I know which routinely suffer from this problem are Mk2 puntos and peugeot/citroen/rover/bmw-mini (which all share the same the same basic gearbox). In the case of the punto because it only seems to affect cars made 2000-2003 I think it's dodgy bearings. I've done a dozen or so of these and thay've all been those years.

 

[Mr Wild]

If you're going to crack open the gearbox probably worth replacing the input shaft bearing and oil seal while you're in there as they're fairly cheap and prone to failure.

If I was taking the box off my car I would personally replace the clutch while I was there.

If it turns out to be the diff, I think your best bet is to buy either a new diff or a new gearbox. But I respect the challenge of doing it all by hand, although I think it may cost you as much if not more.

I think your first port of call should be to disconnect the inner cv's, see if they turn freely and then you can be pretty sure it's the diff.

I have seen an inner needle bearing fail on the drive shaft inner spider, and this caused the failed bearing to sit in the inner CV, and the spider was rotating over it causing the shaft to move laterally out over on every revolution of the wheel and rocking the engine back and forth on its mounts.

If this was the case however, due to the nature of the diff your other wheel should be turning freely.

 

[lance1]

Ok thanks all. Yes whilst the gearbox if off the clutch is a definate replacement. I am searching now for a good second hand gearbox. I want to save a bit of money so I thought doing it myself should save at least labour costs. Thats if all goes as planned . With the money saved I plan on doing the strut top mounts as these were getting a tad noisey on steering lock.

thanks nate.

 

[DaveMcT]

Seriously - Its really not worth the hassle. I'm broke and do most things but wouldn't consider a DIY clutch. That said I would do the gearbox bearing myself and as Mr Wild says its good sense to change it anyway. There is now a guide on the subject.

The bearings are a common type. e.g. the self sealed versions are used in motorbike wheels. You might find a better specification version in a bearing factors.

Find a good small garage - the type of guy who gets work on recommendation. He will have lifts and stuff to do the job without hassle. Check out the recent thread with non working clutch. The guy DIY'd it and damaged the clutch plate so he still had to get a garage on the case. Respect for trying but poor guy must be gutted.
https://www.fiatforum.com/punto/269843-clutch-wont-dissengage.html

 

[DaveMcT]

Love the bearing theory! Unfortunately The only cars I know which routinely suffer from this problem are Mk2 puntos and peugeot/citroen/rover/bmw-mini (which all share the same the same basic gearbox). In the case of the punto because it only seems to affect cars made 2000-2003 I think it's dodgy bearings. I've done a dozen or so of these and thay've all been those years.

Makes sense it is (was) only a theory.

 

[Ziggy122]

if the gearbox itself is still good ie
Nice smooth Changes (no crunching)
And no rattles or Squealing or anything else

get a New differential

If you do decide to get a new G.box - go get a reconditioned box

I've bit the bullet with 2nd box's
and well - i've had rotten luck
1st replacement was Shattered inside
2nd - 3rd syncro was dead and the diff later popped
3rd box (current) Rattles (ratchety) Gears are good, just now very noisey

So i'm having Yet another g.box!
Diff's are easy to replace - since you've got the box already out




Ziggy