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My Turn for the Big Yellow taxi home.


Pete Attryde

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Evening all,

Well it was my turn to get the big yellow taxi home tonight as my 1996 Discovery 300TDi auto lost all drive.

Driving along quite normally at about 30mph just accelerating gently as I was leaving a 30 limit there was a gentle clunk and I had no drive. I pulled on to the verge and tried the following things to see if I could get any drive:-

1. put in diff-lock (to eliminate a stripped drive flange)

resulted in no drive and no horrible noises. The engine rev'd freely.

2. Put it in to low ratio.

Same result as 1 above.

3. put it back into high and took out difflock and selected reverse.

Again resulted in no drive and no horrible noises.

4. Selected 1st rather than D.

Again no drive and no noises.

5. Gave up and rang the RAC.

resulted in two hour wait for the tow-truck but at least the sent a sensible sized flat bed to pick me up on the first attempt.

Whilst waiting for the tow-truck I checked that there is oil in the gearbox (which there is although I can't say if it's the right amount as I was stopped on a slope and the box was warm) and then contemplated what might be wrong and I think that my Torque converter has probably failed as I would have thought that if a clutch pack in the box had failed I would still have been able to get reverse. I am not very familiar with Auto's so can one of you lot with more experience help me out. I will be calling Ashcrofts in the morning but I would like to be able to give as much info as possible.

Just to put a smile on my face when the tow-truck arrived the bloke driving got out and tells me his gearbox had also failed as he could not get reverse, Still pick me up and we managed to get most of the way home with only one gear at about 20mph. He could off-load my Discovery as where I live he would have been trapped, so he took the truck and my Discovery back to the depot and I should be getting it back by lunch time tommorow.

Sorry about the long post,

Pete.

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The torque converter drive plate is a common-ish failure but you normally get a hell of a banging noise like a little dwarf is trying to get out of the bellhousing with a hammer!

The other possibility is the output shaft from the auto box where it engages with the transfer box - the same splines strip as on the manuals, but with an auto you can change it much easier because it is just a stub shaft on the end of the box.

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The torque converter drive plate is a common-ish failure but you normally get a hell of a banging noise like a little dwarf is trying to get out of the bellhousing with a hammer!

The other possibility is the output shaft from the auto box where it engages with the transfer box - the same splines strip as on the manuals, but with an auto you can change it much easier because it is just a stub shaft on the end of the box.

Drive plate very nearly failed on the nas 3 of the 4 or was it 2 of the 3 bolt HOLES holding the plate to the flywheel had sheared due to a blooming great big tear across the plate, held together by it's teeth! But there was a strange noise to which many grown-up's listened and came to the conclusion drive plate. So if silent possibly not the plate which is of course a gearbox out job. Not cheap either and to add insult to injury the new one was water jet cut from a tough steel such as SAE 41-30 and we have about 2 tonnes of narrow strip in stock that I will cut on our water jet next time the nas makes that noise :lol:

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Pete if its the stub shaft splines then i have a spare one off a v8 autobox in the shed at home? is it a zf4hp22 box?

ring me if you want it and i'll get my dad to dig it out for you and drop it round?

Mike

Cheers Mike,

When I get it back (hopefully before lunch) I'll investigate a bit further and will give you a call. Yes it is ZF4HP22.

This may set back the re-wire plans for this weekend <_<

Pete

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silly thing worth checking, only mentioning it as its just happened to me - the fluid cooler pipes going from the box to the rad are prone to cracking and letting the oil leak out quite quickly and you'll lose drive. Ye shall know of this fate by the copious splattering of oil undernath the car.

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silly thing worth checking, only mentioning it as its just happened to me - the fluid cooler pipes going from the box to the rad are prone to cracking and letting the oil leak out quite quickly and you'll lose drive. Ye shall know of this fate by the copious splattering of oil undernath the car.

Yeah thought of that, The pipes are less than a year old and there was no sign of fluid loss so I don't think it's that. Thanks anyway.

Pete.

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Right got the vehicle back and whilst un-loading from the flat-bed tried the in park and see if it rolls thing and it still rolls :P , so I thank Cipx for the pointer as it looks likely that the stub shaft splines have gone. Just waiting for Dave at ashcrofts to call back and i'll order a new stub shaft and a crossdrilled gear for the 1.4 transfer box I have sat in the shed and hopefully I'll be mobile soonish.

Pete.

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Well it looks like my intial diagnosis might be right after all.

I have just jacked a front and rear wheel of the ground and put difflock in and with the hand brake off but the gearbox in park I can't turn the wheels, if i take it out of diff-lock I can turn the rear wheel and the front one turns as well.

with all for wheels off the ground with the engine running I can select any position on the gear selector and I get no drive :( . I also get no nasty noises, there might be a slight hum coming from the front of the gearbox, bell housing area but thats all.

anyone got any ideas?

Pete.

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Pull the pto cover off remove the bearing carrier and the i/p gear

30mins and you'll have a better idea of eliminate another possibility

Right pulled the pto cover and removed the i/p gear, pleasantly suprised to find a cross drilled gear with splines in good condition and the stub shaft splines are also in good nick. I put a spanner on the bolt in the end of the stub shaft and stuck the box in park and upon turning the stub shaft got a definate click as the park brake engaged and the stub shaft stopped turning.

So looks as though it's either the gearbox or the torque converter or the flex plate then.

Keep the ideas coming

Pete.

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Further investigation (with pointers from Ashcrofts). I removed the bell housing cover and with the engine running checked if the torque convert was spinning (it is) to help eliminate the flex plate. also checked if stub shaft was turning with the I/p gear removed (it isn't), am now waiting for a further call back.

I also checked the oil level and it is correct and reasonably clean.

Any one else think of anything I can check?

I think this is going to hurt my wallet :(

Pete.

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Thanks Tony,

I have had a further conversation with Ian Ashcroft and it would appear that the box has failed :( . There is a known weak point within the box which would cause the symptoms. So I have ordered a new gearbox. I have to say that I am so far hugely impressed with Ashcrofts service.

Pete

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Hi Pete,

When are you getting your new box? I have a good zf4hp22 in the unit if you want it? Let me know when your getting the box and i'll come over and help you fit it, or if you can sort transport we can move the 110 outside and you can put it in the unit if you like?

Mike

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Mike,

New box is coming Wednesday, So I am planning to take the later part of next week off to swap it over. Thanks for the offer of both your box and the use of the unit. I will leave the box as I am getting an ashcroft recon which should last longer than the rest of the vehicle, and as I have already started stripping the transmission down I will have to do the job here. Your help would be appreciated when ever you are available.

Pete

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Right after a bit of effort we have managed to track down the issue:-

It appears that I have anasty infestation of Transmission Troll who have eaten my gearbox :P

19-04-08001.jpg

Sorry Mike couldn't resist. :ph34r: .

With Mike's assistance I now have the box out of the car. every thing seems to be in good condition even the flex plate is in good nick so hopefully the new box will see me mobile again.

Pete.

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Right after a bit of effort we have managed to track down the issue:-

It appears that I have anasty infestation of Transmission Troll who have eaten my gearbox :P

a gentle tap round the back of the head should get the troll working flintstone stylee - almost as fast and easier on the fuel too :ph34r:

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Hi Pete...

Sorry to read that your truck was in need of some TLC. Good to see the support of the forums kicking in again... You doing a Tech thread to show how you removed Mikes head and stick it on the gear selector ?

Neil

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