Is my gearbox FUBAR'd?

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Hey all,

I noticed on Sunday whilst at Slindon pay and play site going up a very steep gravel hill that my 80 started juddering quite a lot, I thought it might have been my front wheels slipping but would have been impossible as I had my diff locked? So I thought maybe the hill was too steep so switched to low range and no juddering or anything.

Then on the way home tonight at a set of traffic lights, I wasn't paying attention looked up and noticed they where green so gave it some throttle to accelerate hard away and it did the whole juddering thing again.

It seems to only do it from stationary, when moving in any gear you can apply full throttle and it'll change down (if req'd) and accelerate away smoothly albeit not very quickly. Tried it again on a empty bit of road and it did the juddery thing again.

I check my AT fluid level often as I've got a small leak which is from the gearbox casing where someone has overtightening something and put a crack in it. I wonder why the they where messing with the gearbox anyway?

Any tips or advice? Obviously don't accelerate hard which I very rarely do probably why it's taken me 2,400 miles to find out it's doing it. My worry is that I'm meant to be going to Morocco in it in 30 days and even though I don't think we'll be accelerating hard in it I might be using a bit of throttle to climb rocky/sandy hills.
 

TobyJug

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check your pick-up pipe/ filter in the tank... might be clogged..
There are a lot of threads on this online it's a bit of a common thing dont think you should worry about the gearbox just yet.. check everything else first..

good luck
 

Jon Wildsmith

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Do you have LPG James? If so, have you tried it on both fuels and is it the same?

A judder like that could be a misfire on the engine as well as being something wrong on the gearbox.
 
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Hmm.. I don't think it's that.

The acceleration is still there, the engine is not juddery.
The whole dash area shakes fairly violently.

There is no hesitation from the engine at all and it revs smoothly and cleanly.

Is there any other tests I could try to try and get a better idea of what is going on?
 
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Jon Wildsmith

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If you have LPG I would double check it's the same on both fuels as it's a simple thing to test.

If it's not the engine then auto box judder is usually caused by not enough hydraulic clamping force on the clutch plates. That can be as simple as a poorly adjusted throttle position sensor or as painful as failing clutch plates or oil pump. Can you tell us more about where it's leaking fluid?
 
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I'm running petrol only, no LPG here.

It's leaking slightly from the rear of the gearbox, there are some bolts holding the gearbox or gearbox casing together. The casing around one of these bolts has a hairline crack in it. I think it's loosing fluid out of there, only very slowly though.

Would it help if I get a video of what is happening from the inside of the vehicle?
 

Jon Wildsmith

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is it definately the gearbox that's leaking or could it be the transfer box? I guess I'm asking if you know the difference :mrgreen: Are you checking the ATF level when it's at operating temperature and with the engine running and within 30 seconds of cycling through all the gears?
 

karl webster

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Hi m8, Had the problem with my 80. Got worse and worse and it started to not drop down into first gear when at lights etc. In the end had the torque converter re-done and made a good box out the two. i Would keep my eye out for a spare box as when i had the prob one day it just totally lost drive and that was it. Maybe someone else can shed a different light on it. Hopefully they can,i think you may have to go down the path i did. If you need any advise my numbers on here. karl
 
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karl wester said:
Hi m8, Had the problem with my 80. Got worse and worse and it started to not drop down into first gear when at lights etc. In the end had the torque converter re-done and made a good box out the two. i Would keep my eye out for a spare box as when i had the prob one day it just totally lost drive and that was it. Maybe someone else can shed a different light on it. Hopefully they can,i think you may have to go down the path i did. If you need any advise my numbers on here. karl

Could you describe your symptoms?

Also, I just checked my ATF level after cycling through the gears as Jon mentioned, and it's registering way above the level for hot running. Could this be a bad thing? They obviously have levels for a reason. I'm sure it wasn't that high before and I haven't put any fluid in for about 2 weeks previously it was loosing a noticable amount after a few days.
 
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I'm going to use a brake bleeder to suck the ATF out of the gearbox from where the dipstick goes as it probably isn't doing it any good being so overfilled.

Spoke to one of the techs here who thinks it might have damaged a seal being overfilled. I'll try it again once I get all excess fluid out.
 
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UPDATE-

Gearbox fluid now back down to the levels suggested by the dipstick.

However the problem still occurs. Been playing with it for the last few minutes, it feels like the engine is accelerating faster than the car is and then the juddering occurs. It kind of feels like in a manual car when the clutch is on the way out, do automatics have a clutch?

It will very seldom ever do the juddery thing for me whilst driven normally as I drive around everywhere really slowly hence my 19mpg out of the 4.5 engine. But I a little worried that when I'm in Morocco in some of the steeper hills loaded up with 3 people and stuff I might be using throttle a fair bit. To be fair once it's moving you can apply full throttle and the gearbox won't slip at all.

Also might be worth noting that Ian Rubie spotted that my car has got a gearbox oil cooler fitted to it, it looks like it has been fitted properly and fairly newish. I wonder if the previous owners had a problem with the gearbox previously and it has been damaged in some way.
 

Jon Wildsmith

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Automatic gearboxs have clutches and the most common failure on an auto box is for the friction material to wear out and slip like a manual ... The engine drives an auto box through the torque converter, that's a liquid coupling that will let the engine rev more freely hopefully into its power band so it's normal for the cars progress to lag behind the engine RPM. That makes it a bit harder to say if what you are describing is the normal behaviour of the torque converter or slipping clutches. Might be an idea to either drive someone elses or get them to drive yours for a comparison.

The clutches are engaged by hydraulic pressure. If there is not enough pressure on the clutches for the level of torque going through the box they snatch and slip and cause judder. Every time this happens the clutch plates are getting a hammering, so best avoided! Different amounts of clamping force are applied depending on how much power the ECU/box thinks you are using so that for low power gear changes there's not much pressure and a nice soft gear change but under high power there's high clamping force and a solid gear change. If the ECU/box is not correctly aware of the throttle position it can result in the wrong clamping force which could be your problem.

EDIT: you need to fix this before you go away IMO.
 
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Thank you Jon for explaining that for me.

What is the best course of treatment to fix this issue?
What should I replace or service first?
 

Julian

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Might be worth starting by finding an auto gearbox specialist, where abouts are you?
 
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I work in Epsom. I actually work in the motor trade albeit sales, the clever fixing stuff I'm no good at.

I'm hoping someone in the service deptartment knows a good autobox specialist who can advise me what I need to do.
I have a feeling this may get expensive! Gulp! :oops:
 

Julian

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I had to have a full rebuild on mine, sorry to say it cost me £1500 ish if I remember (trying to forget it really)
 

Jon Wildsmith

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AFAIK the petrol 80 series were fitted with the A343F gearbox which I've not worked on where as the diesels use the A442F which I have worked on. I'm pretty sure the A343F in the 80 will use the same method of hydraulic pressure control though and that would be a cable from the throttle body to a valve on the gearbox valve body. Have a look for the engine end of that and check it doesn't have a lot of slack in it on idle. The more slack the less throttle the valve sees so the less pressure. Take the/some slack out of it and then test drive it. If you go too far you just get a harsh gear change sometimes due to too much pressure.

Also pull the cable a bit by hand to make sure you can feel a bit of resistance and it springs back as the cables sometimes bind then snap and that's worth checking for.
 
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Julian said:
I had to have a full rebuild on mine, sorry to say it cost me £1500 ish if I remember (trying to forget it really)

Was it displaying similar symptoms to mine?
I think we had an Astra recovered in with a faulty gearbox that we sent to these guys http://www.hardyengineering.co.uk/ before, I shall ask around to see if they are any good.

They are either going to say, 'stop being a moron it's totally normal' or as would be my luck 'you can't drive that home or the haydron collider will explode, you have to put a new gearbox in it'.

I might not be going to Morocco after all!

EDIT- Thanks Jon. I shall have a look at that tommorow, I'm at work tommorow anyway so I'll pop it on a ramp and have a look, inbetween of course selling 40 cars as it's obviously going to be busy tommorow, or not!
 

Jon Wildsmith

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The other thing you could check James is if it does it if you select L instead of D to pull away as that uses a different control circuit in the valve body and (for the A442F at least) gives max pressure rather than variable.

The EPC shows a throttle position sensor cable for an FZJ80 so it should be there.
 

Julian

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Julian said:
One of the biggest things to look for on an early 100 series is the Gearbox, There is an issue with the fiber washer breaking down in the torque converter, then being pumped around the rest of the 'box creating issues as it goes.
The problem is you unfortunately can't see anything externally.
The two tests I know of are whilst slowing down it feels as if the auto box is holding on to too higher gear causing a shuddering feel a bit like forgetting to change down in a manual car whilst slowing, the other test is dropping the sump off the gearbox and checking the magnets for debris and the quality of the oil. Obviously the second test is pretty much impossible to do when checking a car out to buy it.
This problem can be fixed by getting the Torque converter reconditioned, costs about £250 ish. But it is a gearbox out job.
The only other caveat is that if it has been broken for a while, you would need to get the box reconditioned. A big job it is a very big box, this cost me about £1250 :o
 
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