ZF GEAR BOX IN B10

[funbus]

Hi guys,

Gearbox in B10 auto, has lost all gears. This seems odd, as when we have had issues with blown gearbox's they may still have reverse or limp forward sometimes.

Gearbox was working fine till then. It was driving, and then lost all gears. I know it would be easy and expensive to get a new box, but does anyone have any ideas or reasons that this may happen to a ZF, they are usually strong and long lasting.

Urgent replies please as bus is off the road.

[The Cap a tan]

The only reasons I know of that a ZF would lose all gears, is that the plug into the computer has wiggled loose and needs to be pushed in, or computer has no power like when the master switch is turned off while the engine is running. Also maybe check she hasn't dumped the fluid due to a leaking seal or fractured case.

[funbus]

Thanks for the information, its a 4HP500 box if that helps anyone. You can move it now when when its cold in reverse slowly.

I am hoping there is an answer, but we cant keep towing it here and there for opinions.

Well checking will continue....

[Guy_Arab]

Thanks for the information, its a 4HP500 box if that helps anyone. You can move it now when when its cold in reverse slowly.

I am hoping there is an answer, but we cant keep towing it here and there for opinions.

Well checking will continue....

I have ZF manual for 2 speed an 6 speed if that helps
Guy Arab

[Herbert]

One possible cause - is the engine idling too high? I had this problem once with a B10M with air-throttle.

[funbus]

Thanks Guy, MTT, Cap a tan again,

Your manuals will unfortunately not help as it a 4 speed, we gave up and gave in, found a very good box in QLD for $3000 + freight. By the time we sorted out diagnostics, towing the carcass around then somehow repairing and rectifying, this is a much better scenario we believe.

Thanks again for your great help as always fella's!

[User7526]

One of the problems that can occur is quite simply a wire that breaks somewhere in the loom, you need to make sure that all of the inputs and outputs to the control box, selector panel and to the transmission itself are all getting the signals/commands that they should be. Another fault could be the selectore panel itself and in extreme circumstances the control unit could even be faulty, you need to know whether all of this stuff is good before you throw in a transmission because if it isn't the replacement 'box won't work. I've pulled so many harnesses apart between my time at Westbus and Busways, don't open them up unless you really need to.

Peta.

[drpeps]

Great to see "Peta mechanic" has returned to the forum. I like reading the well thought out responses.

[AL]

Check your oil level to see if it is burnt or black. Pull out the main filter. When they fail for good they block the filter up with junk which stops the hydraulics and no go all of a sudden. You can run it with no filter to be able to limp the vehicle for a short distance. If this is the scenario though the box is unfortunately no good.

Otherwise it'll be dodgy electrical connection.

[funbus]

Thankyou,

It was a faulty plug in the end , the good boys at ZF emailed me the German diagrams in German!!!!

But it took 2 auto electricians about 8 hours to sort it.

Its worth putting things on the forum, as there is a wealth of knowledge out there from all the forum experts

[User7526]

Glad it worked out, I was seriously thinking that you wouldn't need another transmission.