456 hard gearshift - recommendations for gear oil?

I've noticed that my new 456 is difficult to get into gear, especially 1st and reverse, when it's warm after a journey. I'm noticing this when I get to my destination and find it difficult to park, for instance. Has anyone seen this in their car?

I am thinking that I should try changing the gear oil first, before thinking about more complicated and expensive possibilities. Perhaps the oil is old, low, or the wrong grade, even. So does anyone have recommendations for the best gear oil for the 456? The manual specifies Agip Rotra LSX 75W90. Is that what I should get?

 

Yes, it's strange. I should say that the gearbox will not be really warm, as I'm only making 30km trips and it's winter here, but the shifting is only bad at the end of the trip, not at the start when the gearbox is stone cold. I have no idea what oil is in the gearbox or how old it is. That's why as a first step I'll change it.

 

Thanks for the replies. That 360/430 thread has confused me. It begins by contrasting GL-4 with GL-4 and synchros with gears, but the factory oil says it is GL-4/GL-5. I'm leaning towards using the factory-specified oil for my oil change, at least as a first attempt. Does anyone have negative experiences with the Agip -now Eni- oil?

 

I've just ordered 5 litres of the original Eni (=Agip) rotra LSX 75W90. I'll see whether that fixes the issue. I'll let you know when I've done the job and tested it.

 

I now have 5 litres ready to go in this weekend. What's the best way to do the oil change? It looks to me as though the easiest will be to run a flexible tube from the top of the wheel arch through to the fill hole on the gearbox; is that the way you are doing it?

 

Here's a short report on how I changed the gearbox oil in my new 456, in case it's of use to someone. I'll be reporting on what effect it has had on the quality of the gear shift tomorrow when I have driven the car.

I put the rear of the car on a couple of axle stands, just high enough to be able to work underneath without introducing a large angle of tilt to the gearbox. I then took out the top plug first, in case it was impossible to remove it, in which case, if one has already removed the bottom plug and all the oil, one can't drive the car to get help. In my case it was tough to get both plugs out, as clearly some gorilla had tightened them, but I managed with some effort. The top one required a hexagonal key plus a spanner with just the right shape to fit into the limited space. The bottom one uses a smaller hexagonal key, but has much easier access.

The old oil was dirty, but not terribly so, and was not very low. Of course I have no idea whether the old oil was of the correct type. It would have been better to do the job with the oil warm and less viscous, but I couldn't manage that, so I left it dripping for an hour. There were quite a lot of metal particles on the magnet on the bottom drain plug. Whether that indicates a larger problem with the gearbox should become apparent now that it has fresh oil in it. I cleaned up the magnetic plug, and I cleaned up the copper washers on both top and bottom plugs by rubbing them on a piece of flat sandpaper until they were uniformly shiny before reinserting the bottom plug and washer and torquing it up.

I had thought I'd need a helper, but refilling the gearbox was not complicated to do on my own. I got about a metre and a half of garden hose, which is exactly the right diameter to fit into the upper fill hole, and I ran it horizontally through the suspension, up into the wheel arch and out. I pushed a plastic funnel into the end and fixed the lip of the funnel into the window channel on the door. I could then poor in oil at door level while making sure nothing dripped out underneath. It didn't, and it took all five litres of the Eni Rotra LSX 75W90. There is a little dipstick on the top fill plug to check the oil level. After torquing that back up and setting the car back down, I shall see tomorrow if there is any change in the shift.

While I was under the rear I had a look around and found a couple of things to look at in the future. The rear spoiler is loose at one side. I probably need to take it off to see how to fix it; is it made of fibreglass? And there is a slight leak in a line to a fuel filter near to the rear suspension, that perhaps just needs tightening. But in general the underside is remarkably clean for a 1994 car, I was pleased to see.

 

So the disappointing news is that there is little or no difference to the hard shifting problem after the oil change and going to and from my work; a trip of 60 km in total. Sometimes the shifts are fine, but other times it's hard or impossible to get a given gear. Both first and reverse are on occasion very difficult to get, especially when I stop after a journey and then try to get them for parking. Third gear often grates both going up and down the gears. At the moment the only idea I have is that all this could indicate a general problem with the gearbox. It doesn't appear to fit other possibilities like a clutch problem, which I would think would show up all the time, or a shift adjustment problem, which again I would imagine would cause a given gear to be difficult to get all the time, not just intermittently, as far as I can see. If anyone has any other ideas, I'd love to hear them.