Transmission issues

Member
Firstly thankyou for letting me join .. now if I may pick some brains ?? We have had our 2006 3.0 td for a couple of years now after changing from a p38 . Lovely car and has not really missed a beat until monday just gone .. we were on our home home from holiday when at the top of an incline it dropped into 4th gear the revs went up as if it slipped then lost drive , I coasted down the other side to a stop it let me go into drive and tried to move but very clunky. Got recovered to get it off I had no reverse ?? Engine revs drop but the site as if in park . Put into drive it goes forward but as soon as I throttle up it goes fail safe mode.. I have disconnected props . In drive the lower part of transfer box sounds noisy ?? But will only turn one way even in reverse?? . I have dropped the oil transfer box oil looked ok a bit dark. Transmission oil a light brown with as far as I can see not metal or bits .. have yet to drop sump... up until this point the only fault it had was when towing up hill it would have a slight vibration but would drop into 4th and go ?? Am I looking at another box ?? I am a mechanic but have never stripped an auto box..
Sorry my first post is long boring and asking for help straight away . But dont want to do a box if it's only transfer box
Thanks in advance.
Stew

This is the GM box? @Bemble is the gearbox God.

Grrrrrr said:

This is the GM box? @Bemble is the gearbox God.

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Hi yes it is , good to hear nice to be on a forum where people reply to you .

Stalky said:

Hi yes it is , good to hear nice to be on a forum where people reply to you .

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The GM box often only lasts for 80/100K miles, the valve block is made of cheese. Also the torque converter lock up clutch breaks up knackering the gearbox. The transfer box only turning one way will be due to the gearbox not selecting reverse. Not heard of many problems with the transfer box.

Datatek said:

, the valve block is made of cheese.

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Have often wondered if the parts made from cheese are better or worse than those made of chocolate?

Beneagles said:

Have often wondered if the parts made from cheese are better or worse than those made of chocolate?

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I think chocolate is probably more expensive so beyond the means of Land Rover

Ok great thankyou I have been offered a complete driving box torque converter and transfer box . Does it need to be programmed or just plug and drive . VERRY GENTLY lol

Stalky said:

Ok great thankyou I have been offered a complete driving box torque converter and transfer box . Does it need to be programmed or just plug and drive . VERRY GENTLY lol

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A second hand box is a very tempting option, but it is also a gamble as to when it may do the same as your present box?? Get some quote for a replacement box and converter just so you have all the info. If there is any metal in the box and converter then it will also be in the gearbox cooler and pipe work.
Caution is a winner.

I'm a little hazy on the GM box but try googling Sonnax and see if that throws up a lead. As Mark says, need to fix the underlying problem.

The plan was to put this other box in . Spend a bit of time stripping mi e and rebuilding it then keep as a spare . I have had quotes of 2k up but most with a 6 month warranty.. if I fit myself ... seems a lot of money for a 6 month gamble

Mines just gone in for a gearbox and TC refurb and they quoted me £1500 to remove, recon and refit with the Sonnax valve block. Hopefully that cost won't change when they get into it.