Discovery gearbox suddenly lost gears but now works What gives?

Richard387
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Discovery gearbox suddenly lost gears but now works What gives?

Unread post by Richard387 » February 26th, 2018, 10:06 am

I have an automatic V8 1997 discovery, yesterday i was driving it and suddenly wouldn't get any gears so i towed it home and this morning i put it in high range and drive and it drove so i took it out of high range and still drove.
So what does that mean? Is the gearbox on the way out? Or was there just something stuck in there?

Peter Aawen
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Re: Discovery gearbox suddenly lost gears but now works What gives?

Unread post by Peter Aawen » February 26th, 2018, 12:15 pm

Where were you driving & what were you doing when it suddenly didn't get any gears??

Many 4WD's with 'full time 4WD' have 'transmission overheat protection circuits' built in so that if you are driving in Full time 4WD on loose stuff & making the 'centre diff' work too hard/get dangerously hot when you really should have locked the 'centre diff' to avoid that, the transmission &/or transfer case electronics will shut down to protect the transmission/transfer case from meltdown!!

Sooo, is there any chance you were driving with the centre diff in the 'normal road' selection on a loose or slippery surface for a while?? Even driving only about 30-50 metres on soft sand or ice/snow slippery enough that you get wheel spin at each end can overheat the 'centre diff' enough to make those safety circuits kick in! Basically, if the surface is loose enough for a gently swung foot to kick up loose debris or it's soft/slippery enough to compromise traction &/or get wheel spin at both ends while driving normally, you should seriously consider selecting 'high range' or locking the centre diff/doing whatever it takes to deliver drive equally to both ends in order to avoid cooking the centre diff or the gears/electronics that emulate that - and even vehicles with traction control &/or electronic systems that vary the delivery of drive to each end can suffer from this!! Hey, overloading the ABS circuits thru traction control operation can do it too!! :eek:

So once again; where were you driving & what were you doing when it suddenly didn't get any gears?? It could well be that you overheated the electronics &/or the transmission fluid so the protective devices cut in, and once everything had cooled down again, it's all back to normal.... at least until you overheat things again!! ;) Or it could be something else entirely?! :confused:
An Ex-Service person is someone who thought enough about their country & how great it is, how lucky we are to live here, to write a blank cheque made out to 'The People and Commonwealth of Australia' for the value of 'Up to & including my Life!'

Richard387
I'm new, be nice!
Posts: 9
Joined: February 11th, 2018, 3:03 pm

Re: Discovery gearbox suddenly lost gears but now works What gives?

Unread post by Richard387 » February 26th, 2018, 4:32 pm

Ok, hopefully it just got hot.
It was just sitting in my driveway for about 2 weeks then on the weekend i decided to take it for a drive around the block in 2wd ( all asphalt ) and in about 500mts is when it cut out

Peter Aawen
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Re: Discovery gearbox suddenly lost gears but now works What gives?

Unread post by Peter Aawen » February 26th, 2018, 6:47 pm

Yeah, that might not be a 'overheat protection circuit' issue!! I'd guess it's more likely going to be a low fluid or blocked filter issue!! When was the transmission last serviced properly, ie trans fluid & filters changed, belts etc checked & adjusted & all that stuff??? Might be time.... ;)
An Ex-Service person is someone who thought enough about their country & how great it is, how lucky we are to live here, to write a blank cheque made out to 'The People and Commonwealth of Australia' for the value of 'Up to & including my Life!'

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