Hydrostatic transmissions

[Murph7355]

I'm hoping someone will be able to help with my lack of logic with a fault I have on a belt driven hydrostatic transmission.

Basically I'm getting no drive as soon as I try to engage the transmission (forward or reverse).

When idling the transmission pulley can be made to spin (it's stopped if unaided) by flicking the drive belt. Engine pulley works fine at all times - engine runs at a constant speed.

Then as soon as you try to engage drive it stops - the belt doesn't slip at the transmission end but thinking about it as I write, it must be slipping at the engine end (I'll check this tomorrow).

The transmission was low on oil so have topped that up (probably a tad too much) thinking that might be the problem. The belt also feels quite slack, but I can find no means of tightening it up.

So I've been thinking that the transmission itself is probably buggered. However, writing the above I'm wondering if the belt is too worn/loose and is therefore slipping at the engine end as soon as it needs to do some work...

Anyone with better ideas (especially from those who really know how these things work )? Belt's probably worth trying anyway as they're not daft money and I can almost certainly sort it myself...

[Steve_D]

I can't give you an answer but would suggest you post make and model etc of the car so that those who can answer have a better chance. Also some issues are model specific (they all do that Sir).

Steve

[bearman68]

It would seem to me that the transmission is buggered. If the input to the transmission is turning, the drive belt from the engine is OK. What's not happening is the drive from the transmission input pulley is not being transferred anywhere else - hence it's buggered. (my logic anyway)

[Murph7355]

That was my initial thinking too.

It's not car, but a Countax tractor

[Madrabbit]

On my Countax (K18/50), there's a lever at the back that disengages drive to the transmission - effectively puts it in freewheel - so you can move the tractor manually. I've jumped on mine a few times and had no drive forgetting I'd pulled the lever out!

[Murph7355]

Madrabbit said:

On my Countax (K18/50), there's a lever at the back that disengages drive to the transmission - effectively puts it in freewheel - so you can move the tractor manually. I've jumped on mine a few times and had no drive forgetting I'd pulled the lever out!

Thanks madrabbit - it's not that unfortunately. Firmly in the correct position.

Next trials with it are on Tuesday when I'll try a belt...but I'm fearing the worst

[Murph7355]

Just in case anyone ever searches...

Transmission was fine (though the oil top up was badly needed) and the belt was OK. Problem was with the tension...

Auto-tensioning system that was being compromised by a bolt that had fallen out and was preventing the brake pedal releasing fully (it evidently brakes by loosening the drive belt).

Running better than ever now and something new learnt