CVT Variomatic Problem

[petefarrell360]

I was recently enlisted to help a chap who has a H reg 340 variomatic. It pretty much made a lot of noise then stopped moving....... He got it towed back and assumed the drive belts had broken. When I went to look it was infact the clutch, which had never been adjusted from new, and at 38000 destoyed itself.

Anyway, managed to somehow find a brand new one, fitted that, with help from Andy (many thanks again mate!) and also corrected some muppetry where the wrong rotor arm had been fitted, thus meaning it had slipped and was causing all sorts of timing and running problems. Well spotted Andy.

Roll on a few months and I get a call, it had made a loud bang, then some nasty noises. He's stopped, looked to see what was up, found nothing, so slowly drove home, but there were still scraping noises and vibration.

I suspected one snapped belt this time, however they were Roulands belts, replaced probably 6 or so years ago, but looked in really good condition.

No, what had actually happened was the large nut that holds the secondary drive pulleys together on the shaft had come off, and was thankfully laid in the plastic guard cover. The secondary pulley had moved as far as it could off the shaft, somehow stopping short of hitting the rear flexible brake hose, had eaten through the plastic guard and was stopped by a small bracket from the boot floor......... just!

Now, has anyone ever heard of this happening before?

My guess is that as they are Roulands belts, it wasn't done at a Volvo garage, I'm getting him to check through the paper work to see where it was done when the previous owner had it. I'd imagine they weren't too hot on the CVT transmission, didn't have the Volvo green books and on seeing a large nut on the end of the secondary pulleys decided they must come apart that way to change the belts. So instead of doing it correctly, took this one off, found it was wrong and put it back on.

I managed to put everything back together with the aid of two F cramps to wind the pulley halves back together onto the shaft and got the nut back on, and got it torqued up to 190 Nm as it should be. While I was at it I changed the oil in the drive units, the secondary unit oil was as black as black, probably being the original oil.

As another question, it states that there is a small amount of ATF in the assembly, and as the seondary pulleys came apart and I was able to see the slotted drive shaft from the seconday drive unit, would this have leaked out and now be empty? I'd imagine the only way to renew this is to remove the entire unit to work on it on the bench.

Cheers,

Pete

[antiekeradio]

unfortunately this is not a unique occurence; i have heard about it happening before.

there is no lubrication needed on the outside. if the oil in the pulley stayed inside you'll be OK on that point.

were the threads damaged?? if not, putting back the nut with some red locktite will be all that is needed to prevent further problems.

sometimes the splines on the shaft get worn away while the nut is coming loose; this does mean trouble because the forces on the nut will become larger than when the splines are in good shape.
sometimes it is needed to weld the shaft and nut together...

[petefarrell360]

Ah thanks for the reply!

The thread didn't appear to be damaged and neither did the splines luckily. I planned to use locktite, but didn't have any to hand. I had actually considered a blob of weld on the nut to the shaft, just to be super safe.

I think rather than going to the hassle of red locktite and removing it all again, clamping the pulley halves together etc a blob of weld is going to be best.

I'd imagine it's always the same side that comes loose due to the way it spins in relation to the thread?

In some ways I'm glad it isn't a unique experience, but it does make me worry slightly about my own vario.

Thanks once again!

Pete