Volvo 340 Automatic Gearbox

I have a Volvo 340 1400cc automatic and there is a gearbox problem, If it were a manual gearbox you would say the clutch was slipping, basically when you accelerate it revs a lot before starting to move off slowly.

Does anyone know how this can be fixed? I only need a temporary bodge as it is a scrap car I am using for banger racing (demolition derby) and it will not be on the road.

Also is there a way of checking or topping up the automatic gearbox oil?

Any help would be appreciated.

Dave

Your car does have a centrifugal clutch which should start to bite before 1200 rpm and should be pulling well by 1700. If this is not so then it may indeed be slipping.

You can check the zero torque speed by jacking up the rear wheels, and raising the engine rpm with forward gear engaged. You can't do this on the ground without gear engaged because there is a declutching servo which operates in neutral and when the button is pressed to move the gear selector.

The clutch is adjusted by means of shims. Measure the clutch gap by inserting feeler gauges between clutch and flywheel. Gap should be 0.4 - 1.0mm. (Mine was 1.8mm when I looked and the clutch was still working fine). If it's over 3.5mm then the clutch is totalled as there are only 3.0mm of shims in when the clutch is new. (Expensive - 150.00GBP if you change it yourself).

If the gap is too big you need to remove shims from between the clutch and the flywheel. There is an article on this on the club website. Torque the bolts to 15lbf and don't burr the allen key holes or you'll have to take the engine out! I use a large torque wrench and a brand new hex bit to undo them.

Remove the same thickness of shims from all three sets. Don't try to get under 0.4mm or the clutch will drag and you won't be able to engage gear. If you find it does anyway then put back some of the shims.

The auto box has two gear cases, each with its' own level plug. Check the levels like any manual gearbox and top up with 80w/90 gear oil. These oils should be changed at 24,000 mile/2-year intervals.

You could also have a problem with belt tension. While you are checking the gear oil, slide a feeler gauge between the rear pulley halves. There should still be 1.5mm of gap between these with the car stationary. If not, loosen all four bolts on the rear casing so it can move and use the screw jack in the middle to jack the gearbox halves apart. They will only move a certain distance and if you can't get 1.5mm pulley gap on both sides then the belts are worn out. The gaps may be not more than 1.0mm different from each other and if they are more than this you can try swapping the belts side to side.
DON'T FORGET TO TIGHTEN THE REAR GEARBOX MOUNTING BOLTS!!! We dont want it to fall off while you're driving.

[Peter Milnes]

Are you sure that it is a centrifugal clutch? According to my Haynes that is reserved for DAF 55s and lesser numbers. My Volvo 66 has a vacuum operated clutch which is controlled by an electrically operated valve. I would suggest that the problem lies in a vacuum leak to the clutch servo. The problem is easily solved by changing the leaking piece of hose.

All the best, Peter

340 CVTs definitely have a centrifugal clutch though it does have a vacuum operated servo that alters the engagement speed slightly, enabling easier gear selection.

If the hose leaks or there is an electrical fault in the control gear - a microswitch in the gear selector - this gives a graunchy and stiff gear change but the clutch does not slip.

One question that I would ask the OP is if he has ever driven a CVT car before? Revs going up and staying there while the car "catches up" is quite normal. The engine speed rises, if you floor it while driving, at a different rate to the apparent speed rise and this feels like a slipping clutch to the uninitiated. The gearbox has merely reduced its gear ratio however.

Will Plummer

Hi, thanks for all the information. I will let you know how I get on.

In response to your question, Will. I haven't driven a car of this type before but the amount of revving and "catch up" seems excessive, it seems to be if you put your foot down there's at least 2 seconds before the car starts to move forward, and it does it very slowly. The previous owner said it hadn't always been that bad.

Dave

..also, could anyone please give me a link to the article on clutch & flywheel shims?

Thanks

Dave

Here's the link


http://www.volvoclub.org.uk/cvt_clutch.htm

Hi Dave

2 seconds does seem to be a bit on the tardy side - my 340 CVT can move off quite smartly from a standstill. In fact it will show many newer cars a clean pair of heels at roundabouts etc. That said they usually catch me up after about 5 seconds ....

Is it worth doing all this work for a car that`s going to be demolished in short order?

Will Plummer

Hi Will

If I can't rectify the problem I will race it anyway but it would be nice to make it competitive, it's a strong car and if I can keep up with the others I might be able to get a few laps. But the way the gearbox is at the moment everyone else will catch me!!

Dave

Just another quick question, does anyone know what wheels will fit a 340? I want a few spare wheels (cheap or free, from scrap cars etc) for the car but they can be anything as I'm banger racing it. are there any wheels form other makes that have the same stud pattern?