GD290 gearbox stuck in reverse

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lambaj
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Joined: 08.01.2009
Location: Basildon

Hi Folks

Has anybody seem this problem before so I can try to save a huge bill!

The gearbox on our GD290 LHD, 5 speed manual 461 LWB has gone wrong :cry:. 1st symptom was the gearbox would jump out of reverse, but now the problem is it will not come out of reverse...... even though the gear lever does......
So, when in neutral, you lift the clutch and go backwards. Fine
When you select 1st, 2nd, 3rd, 4th or 5th, you go nowhere and the engine stalls. Obviously the reverse selector has remained stuck in, so selecting a forward gear just locks the box solid. If you put the transfer case in neutral, and gearbox in neutral (read reverse), there are no nasty noises or crunching sounds, so I am guessing that a selector fork or selector link has lost a pin/bolt/spring and is simply not pulling the reverse idler gear out from the gearset. The gear lever is very sloppy now, but all gears can be found by stiring about a bit.

Not expecting this to be a common problem, but you never know. Generally our G is in excellent condition, but has been offroaded a lot recently. Nothing too extreme, but it has been door handle deep in muddy water, working hard in deep ruts and fully "exercised" on non-rocky test tracks requiring all the capability of the ol girl. I doubt any of this would hit the box as it is well out of the way, but the chassis has had a few firm groundings (again not on hard stuff).

Any thought appreciated, and I will let you folks know the outcome (and the bill!)

Cheers
Tony

Pistonhead
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Joined: 16.12.2006
Location: Loughborough
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Re: GD290 gearbox stuck in reverse

Hello Lambaj,

Sorry to read of your problem. The job will require some degree of strip-down, in order to ascertain the problem. Your prognosis is probably, correct, something has had to come adrift on the selector mechanism.

I would ask you to firstly, dislocate the selector rods from the levers by the side of the gearbox (g/box), I am going to assume this will be on the nearside (n/s) of the vehicle. Once disconnected, check the positions of the levers. They should be centrally positioned, i.e. the levers should all face a 12 o’clock position, for neutral gear.

The levers will move one position either clockwise or anti-clockwise, from the 12 o’clock position to be in gear. Since, your gear already is suspected to be stuck in reverse, one of your levers will not be in a 12 o’clock position, given this, try and select a gear with any one of the other levers; what you should find is that you cannot do this. This normal.

Then de-select the reverse gear, by facing the lever at 12 o’clock. Choke the wheels of your car. Handbrake applied, to test you are truly in neutral; with your clutch pedal depressed, start your engine and slowly ease off your clutch pedal, with the g/box in neutral, naturally you will be able to fully lift off your clutch pedal.

If however, the gear remains selected, although the lever may have neutralised, a further strip-down will be necessary. Drain your g/box oil, remove the selector lever cover, you will have to gently tap out the cover and lightly tap in the selector rod into the box. With the cover adrift from the g/box, with your fingers supporting the selector forks at the same time, push the selector forks away from the cover, towards the g/box, and then you will be able to remove the cover completely.

With more visible room, you can inspect your gearbox and some anomaly should manifest. Probably this is the stage at which you hand the job to a professional, if you cannot solve it for your self. If it is a matter of simply tightening a dislodged bolt back on, then I would suggest you use a thread lock sealant to glue and keep the nut secure.

Regards,

lambaj
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Joined: 08.01.2009
Location: Basildon
Re: GD290 gearbox stuck in reverse

Hi again

Well, the G has a bent selector rod, spares ordered from Germany, be about a week.....
God knows how the selector rod got bent. I shall be looking to ask some probing questions of the people who last took this vehicle out.....
I'll post more info as I get it. At least the box is not Fubar'd and hopefully can be repaired in situ.
So, only the aux drive belt, tensioner, rear brakes and handbrake to sort now.....
Thanks to Pistonhead for your inputs.

Cheers
Tony

Pistonhead
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Joined: 16.12.2006
Location: Loughborough
GWOA Groups: Committee, Members
Re: GD290 gearbox stuck in reverse

You should be able to straighten the selector rod as a contingency in the vice, purhaps you may need to heat it first.

Goodluck,

lambaj
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Joined: 08.01.2009
Location: Basildon
Re: GD290 gearbox stuck in reverse

Hi Folks

Been A while since I followed this story up. In the end, the garage concerned tried to change the selector levers only to find the problem remained. They also changed the gear lever housing, also to no avail. At this point I needed the vehicle back (about 5 weeks) so the supporting contract company called in an apparent Merc Gearbox specialist.
Net result of all this is that the G now has a brand new gear box. I never received a proper diagnosis of the fault, and thank God I don't have to pick up the bill !
So, in the end, the 'G' is in a good place with a new box, and new Aux belt, rear brakes and a handbrake that actually does something.

Now its starting to do odd things to the idle speed (hunting) when the A/C is on......
Oh Boy !

Cheers
Tony

mgrays
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Joined: 07.11.2005
Location: Aberdeen Scotland
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Re: GD290 gearbox stuck in reverse

Was this a Getrag gearbox then?

Mine and the original family owned G (when new) would jam in 3rd gear.

Solution is a smart smack away from you into 1st/rev gate which usually dislodges it. It is a fobile of the remote gearchange linkage not the box IMHO. Eventually the gear stick becomes bent and you need to pull it back towards you (RHD) to straighten it..

The new at that time G got a new gearbox after a while..£3.5k or more sticks in my mind from 20 years ago..