2.5 DSE Automatic - No Drive

This is a repost as I previously omitted a title:-

My DSE refuses to run. I was driving up hill when the revs started to surge associated with loss of road speed, eventually after a few minutes ending up with high engine revs and zero progress.

There was no joy in low ratio or any other gear option, after a few minutes with the engine off the car would drive for maybe five minutes and after several stops I was able to get home.

The next day I drove it a few yards, stopped and left the engine idling for five minutes after which it refused to move again. The gear box oil level is a clear pinkish colour but is 100mm higher than the top mark and has been since I bought the car over a year ago and it had not reduced.

There are no warning alarm messages showing, can anyone out there tell me what I need to worry about.

JW you have got all the answers possible on other thread. Drive selection is mechanical no electric involved. So the problem whatever it is will be internal. If the forward clutch had gone, you should still be able to engage the reverse clutch, sounds like a loss of fluid pressure for some reason. In any case it's box out i am afraid.

wammers said:

JW you have got all the answers possible on other thread. Drive selection is mechanical no electric involved. So the problem whatever it is will be internal. If the forward clutch had gone, you should still be able to engage the reverse clutch, sounds like a loss of fluid pressure for some reason. In any case it's box out i am afraid.

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That's odd Tony, I thought that drive selection was effected by the solenoid valves driven by the ECU. Otherwise you are right the box is stuffed.

Datatek said:

That's odd Tony, I thought that drive selection was effected by the solenoid valves driven by the ECU. Otherwise you are right the box is stuffed.

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As i read it drive selection is mechanical. Changes are electrical. When you start engine pump fills torque convertor hence oil level drops. When you select drive forward clutch is feed oil via a manual valve to engage it. Dependent on position of gear selector box is electronically restricted to a set change pattern. When you select reverse. Oil is fed to reverse clutch via a manual valve to engage that. Keith have a read of gearbox operation in RAVE and see if you get the same impression. Just read it again still sounds same to me. It says a manual valve controls fluid feed to D,P,R and R positions. Changes are made by electronic MV (movable valves) means.

wammers said:

As i read it drive selection is mechanical. Changes are electrical. When you start engine pump fills torque convertor hence oil level drops. When you select drive forward clutch is feed oil via a manual valve to engage it. Dependent on position of gear selector box is electronically restricted to a set change pattern. When you select reverse. Oil is fed to reverse clutch via a manual valve to engage that. Keith have a read of gearbox operation in RAVE and see if you get the same impression. Just read it again still sounds same to me. It says a manual valve controls fluid feed to D,P,R and R positions. Changes are made by electronic MV (movable valves) means.

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OK Tony, I see where you are coming from. The lever selects forward or reverse and the changes are electronic But it still seems to me that the electronic control valves have to operate to engage the appropriate clutch to activate a gear as there is no other apparent connection to the clutches A failed sprag clutch will stop the vehicle moving in drive but by selecting 1st it will move as it will by selecting reverse

Datatek said:

OK Tony, I see where you are coming from. The lever selects forward or reverse and the changes are electronic But it still seems to me that the electronic control valves have to operate to engage the appropriate clutch to activate a gear as there is no other apparent connection to the clutches A failed sprag clutch will stop the vehicle moving in drive but by selecting 1st it will move as it will by selecting reverse

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It would seem to me that engagement of the forward and reverse clutches is done conventionally by the valve block, as it was in the earlier model box. Only the gear changes and various interlocks are done by electronic means. If he can get drive in position 1 then change up manually i think that is the forwards sprag clutch failed. If he can get reverse that would indicate forward clutch duff. Both senarios would indicate oil pressure is available. I find it hard to believe both sprag clutches have failed along with forward and reverse clutches. So it only leaves lack of oil pressure as the cause. I have never had one of these apart so am only going off RAVE description of operation. Anyway i think we can agree it's a box out and have look jobby. Unless someone with more info can give him a clue. Also from his description the oil level does not go down when engine starts, this would indicate to me that torque convertor is not being filled.

you are right in that it reverse and drive are selected maually with solenoids been used fot t/c lock up and gear changes ,normally rear most clutch burns out loosing drive in r and d with clutch A been burnt as well ,normally free wheel in clutch c gives problems ,when improved from hp 22 it was this free wheel and clutch A that where beefed up,most times it would be either clutch A or/and F but oil not discoloured ,ive found epicylic gear hubs broken loosing drive as with epicylic which need one part held to transmit drive,but its rare ,as is and just as likey for pump to fail,or oil pick up (common if filter changed carelessly) or internal seal ,but would be worth testing pressures ,but as wammers says will still end up with box out but would be nice to know if was pressure issue where in system it occured pump or after