Gearbox issue

Q I would appreciate any advice you can offer on my 2014 Iveco Daily 35S 130 bought secondhand in 2015 with 15,300 miles. When I bought the van, I noticed that the gearchange in the six-speed box was notchy, most noticeably when going from 1st to 2nd, where it felt like it was going to crunch and you had to wait for synchromesh to catch up; it was worse when cold. Being still under warranty,

I took it to the dealership and they reckoned it was the selector that wasn’t adjusted correctly, but adjusting it made no difference. I was told by the mechanic that the gearboxes were not ideal.

I put up with it for a few months, then changed the gearbox oil and used the recommended PETRONAS Tutela 75W/80 API GL-4, but this seemed worse. After some research, I read that Redline fullysynthetic GL-4 gear oil was recommended for smoother gearchanges and this seemed to improve it a little, although it was still tricky going from 1st to 2nd.

The next thing I checked was the clutch slave cylinder arm travel, which seemed low compared to what was quoted in the workshop manual. The master cylinder and slave were replaced as they are a combined sealed part, but this made no difference.

I have now run out of ideas and the van has still only covered 20,000 miles. I would have thought the gearbox and clutch would be like new at this mileage. I wondered if there is problem with possible water in the gearbox (although none was evident when it was initially drained). I believe the previous owner parked it outside, if this is relevant. John Turner

A As you have changed the gearbox oil, I would not suspect that water ingress is an issue. If this were the case, you would certainly have seen emulsification in the old oil. From your description, I feel the source of the problem is the clutch hanging up. When I read that you had measured the clutch throw from the cylinder and replaced the clutch slave and master cylinder, I thought that you may resolved the problem.

Having eliminated the hydraulics, and given the low mileage of the vehicle, I suspect that the clutch is hanging up due to light corrosion on the input shaft splines. This will inhibit the movement of the centre plate on the shaft and can cause the clutch to continue to drag when the clutch is depressed. This is a common occurrence on some vehicles and the cure is usually to remove the gearbox and clean and lightly grease the input shaft splines.

There is also the possibility that the clutch centre plate is distorted slightly, which should also be checked when the gearbox is removed.