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Old 02-08-2012, 15:31   #1
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md7a gearbox trouble

We've got a 1980 Md7a with the MS gearbox that won't quite go astern. When the oil in the box is cold it works, when the oil warms up it will not engage. We have tried putting 60 grade oil in that's an improvement because at least the shaft turns .... very slowly, We have also just put a new cable in so it's not the connection to the box that is slack. Anyone got any suggestion 'cause taking the thing out is a last ditch resort.
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Old 02-08-2012, 17:17   #2
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Re: md7a gearbox trouble

You dead sure the fault is not on the cable side? I mean you had it disconnected from the cable and cannot switch gears by hand?

We had similar problem here but it was bad cable alignment/tuning.

b.
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Old 02-08-2012, 23:15   #3
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Re: md7a gearbox trouble

We have tried to switch the gears without the cable connected and it still won't engage astern
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Old 03-08-2012, 07:25   #4
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Re: md7a gearbox trouble

Assuming the oil is OK and the cable is not the culprit:

If the issue developed over time in a gradual manner, I would suspect the liners.

If the change happened from day to day I would expect a mechanical damage to one of the components.

Both liners issues and mechanical failure require taking the box out ;-(.

I have read of many such cases with MS and MSB - as they grow old they sometimes refuse to engage in on of the positions when the oil gets warmer.

The box can be removed and opened for inspection. A good garage will re-do the liners but if any mechanical failure is found, some original VP parts are no longer available - then repair depends on ability to source or manufacture the replacement part. There is an online catalog that quotes availability and the prices too.

If there is a VP shop in your area then and experienced VP mechanic will be able to tell you the exact cause without taking the thing out. AT times, they will tell you what the issue is just by listening to your story. 99% of the time such a diagnosis is well worth the hourly they charge.

I am not a mechanic just a user so listen to all other inputs before you commit to removing the box.

barnie
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Old 05-08-2012, 23:40   #5
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Re: md7a gearbox trouble

Thanks for your reply, all these problems take time to solve but with input from many people we might have a solution keep you posted
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