HELP NO REVERSE

[Guest]

I have a BMW D7 single cylinder motor with a HBW 50 gearbox. When i engadge reverse the motor dies even after i have warmed up the engine. Sometimes the motor does not cut out but will not pick up reves.No prpblem with forward.I have sent it back 3 times to the agents and even they are stumped.The shaft turns freely. Thanks Mike.

 

[Guest]

May I ask who the agent is? NM

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[Guest]

Try another agent, and suggest this:-

Mike,

Not familiar with the HBW myself, but most reversing gearboxes work by engaging clutches or break-bands to allow or prevent, rotation of the appropriate gear clusters. Older models mechanically, nowadays this is all done by hydraulic pressure.

With bad wear, incorrect adjustment, or blocked oil control valve-gear, I have actually seen a gearbox in both ahead (a lot) and reverse (a little) at the same time. This exhibited similar symptoms as you describe, obviously the engine was not too keen and in this case, flogged itself very hard to try and power the shaft. A mass of heat was produced and quite a bit of evil smelling smoke from the gearbox as well.

Does your engine pump out lots of black smoke when it IS running in reverse? This would indicate that it is working very hard to power the gearbox.

I would assume that prop clearance/shaft movement has also been checked here? There is always a certain amount of for and aft movement, could something be fouling somewhere? It shouldn’t be too much trouble to disconnect the propshaft and try the engine/gearbox combination unloaded.

Does your agent need a good mechanic?

 

[Guest]

Symptoms sound as though forward and reverse cones are being energised at the same time.

Try thinner oil in the box - if that doesn't work, you'll have to strip the box and check the spacers on the shaft.

 

[Guest]

Re: May I ask who the agent is? NM

the agents are Z.F. in isando johannesburg

 

[Guest]

Thanks.....not the one I\'m currently in an argument with!

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[Guest]

Hurth HBW 100

I've looked at a drawing of the big brother of the gearbox you've got which is a drop-centre box with a sliding cone common to the two cone clutches for forward and reverse.

I would suggest the following actions - 1. Check the forward/reverse lever on the outside of the box is hitting its stops when the remote-control activates it. You are probably not fully disengaging from forward and only partially engaging reverse.

2. If that doesn't cure the problem drain and refill the gearbox with SAE10 or 15 oil.

3. If that doesn't clear the problem, have the box out and stripped, but not by the "agents" you've already approached

 

[Guest]

What oil are you putting in your g/box Mike, it should only be automatic transmision fluid.There are two sets of clutch plates in the g/box if the prop shaft is free to turn in neutral I would have thought you could not be both in forward and reverse, hope this helps.