Unpleasant gearbox fault X308

Unpleasant gearbox fault X308

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BOH

Original Poster:

134 posts

212 months

Wednesday 5th September 2007
quotequote all
Twice now in the last 3 months when 'booting' on the dual carriageway my X308 Sovereign did the most bone shacking gear changes I could imagine. Thought for a moment something had locked completely solid.

Subsequent changes pretty rough, however once engine switched off and restarted, the changes were mysteriously back to their normal smoothness.

Once this happened when the car had just undertaken a 150 mile journey, and the other after about 5 miles from cold.

The car has approximately 95000 miles on the clock.

Any ideas?

Trooper2

6,676 posts

232 months

Wednesday 5th September 2007
quotequote all
Any warning lights or messages in the message center when this occurred or are they present now?
Did the battery get drained low, perhaps, before this happened?
Is the sport mode button engaged?

First thing to try is fully charge the battery then disconnect the negative lead for at least 2 minutes (module hard reset). Drive it and see if it occurs again.

Jags, because of all the electronic controls are very sensetive to voltage, if the battery goes below a certain voltage the modules can get confused and need to be reset. It's an easy place to start anyway.


GavinPearson

5,715 posts

252 months

Thursday 6th September 2007
quotequote all
Transmission has defaulted and gone into 4th.

This is seriously bad news, A clutch is failing.

Change gear oil immediately if you want the trans to last any length of time, or have it rebuilt.

BOH

Original Poster:

134 posts

212 months

Thursday 6th September 2007
quotequote all
Hi, many thanks for your advice.

So would changing the oil extend the life of an already failing gearbox?

I would imagine any gearbox work would be expensive, perhaps the best course of action would be to do nothing, wait for it to fail and replace it with a recon unit - I've seen them advertised at £1600 inc. fitting.

Strangely enough the cruise control wouldn't 'arm' - the red light wouldn't illuminate when the event happened.



Edited by BOH on Thursday 6th September 15:28

GavinPearson

5,715 posts

252 months

Friday 7th September 2007
quotequote all
BOH said:
Hi, many thanks for your advice.

So would changing the oil extend the life of an already failing gearbox?

I would imagine any gearbox work would be expensive, perhaps the best course of action would be to do nothing, wait for it to fail and replace it with a recon unit - I've seen them advertised at £1600 inc. fitting.

Strangely enough the cruise control wouldn't 'arm' - the red light wouldn't illuminate when the event happened.



Edited by BOH on Thursday 6th September 15:28
Changing the oil will extend the life noticeably, the fact that the oil has probably lost most of the additives' usefulness will not help gear or clutch life.

Just bear in mind that the rebuilt gearbox is exchange and if you supply them with scrap then you need to pay a (big) core charge.

Your call.

BOH

Original Poster:

134 posts

212 months

Thursday 13th September 2007
quotequote all
Had a spot of trouble starting the old girl yesterday. The starter motor turned over the engine vigorously, but it wouldn't fire. After taking the key out of the ignition and locking and unlocking the doors, it started at the next attempt. Then reversing out of the parking space, all didn't seem right as it felt rather unresponsive to the throttle. Put her in D and she pulled away very slowly and Gearbox Fault was annunciated. Switched off the engine and she started immediately, felt normal and gearbox functioned correctly without the fault annunciation.

Any thoughts?

GavinPearson

5,715 posts

252 months

Friday 14th September 2007
quotequote all
Gear cable adjustment.

BOH

Original Poster:

134 posts

212 months

Friday 14th September 2007
quotequote all
Hi Gavin,

Thanks as ever for your learned thoughts.

I wonder if the gear cables could have anything to do with my more unpleasant episode at the top of the thread?



GavinPearson

5,715 posts

252 months

Friday 14th September 2007
quotequote all
No.