P38 gearbox troubles

[willem]

G'day guys,

My 99 P38 4.0 is having a sulk about something. :(

Yesterday when going up a hill coming out of a roundabout the gearbox seemed to 'declutch and reclutch' three times in quick succession. It 'declutched' and the engine revs went up, 'reclutched' and they went down as the load came on again. All this happened in a space of a second or so. Then a 'Gearbox fault' message came up. The car kept driving but without the gear indicator showing, which, I think, means that it is in a 'limp' mode and stays in the gear it was in.

After it was switched off and later restarted the error message had reset and it ran fine ... except that I could make it surge a bit - the same sort of 'declutch/ reclutch' thing but much milder. Otherwise the gearbos does everything right - changes at the right places, smooth ... etc

Thinking back, the 'declutch/ reclutch' thing has been happening for a while, but only mildly.

The trans was serviced this week and the transmission people reported no problems.

Any ideas?

Thanks

Willem

[green_rangie]

Hi Willem,

Did they change the fluid when they serviced the trans ?

I wonder if it was the correct fluid ? Also, was it the same as what you had before - when changing the fluid they would have need to do to some length to do a complete change rather than a partial change that you do when you just drain and fill it and perhaps there is an incompatability ?

Cheers, Steve.

[willem]

Hi Willem,

Did they change the fluid when they serviced the trans ?

I wonder if it was the correct fluid ? Also, was it the same as what you had before - when changing the fluid they would have need to do to some length to do a complete change rather than a partial change that you do when you just drain and fill it and perhaps there is an incompatability ?

Cheers, Steve.

Thanks, Steve, for your response.

I'll check that out, but I do think the problem was already there before the service. I think its an electrical/ electronic problem ... but I don't know.

Willem

[mike 90 RR]

Yesterday when going up a hill coming out of a roundabout the gearbox seemed to 'declutch and reclutch' three times in quick succession.

Tell your trans people to RECHECK the level of trans fluid .... ;)


If it all settled down on level ground ... then it sounds as tho the trans pump got a heap of air, rather than fluid ....




By the way ... a pump sucking air will = shagged auto pump, etc

Mike
:)

[PaulieJ]

Hi Willem,

Following on from Mike 90 RR

Do you know if they replaced the trans filter?

I was having trouble with my '00 P38 not selecting gears properly last year and it turned out to be a split O-Ring on the trans filter - this was causing the fluid to become airated and resulted in delayed/harsh gear selection...

Paul

[willem]

Thanks for the input guys.

Because the problem pre-existed the auto trans service I don't think the service was the problem. Also, changing gear is not a problem - it changes as it should and when it should.

I was going up a long moderate steep hill this morning at relatively low speed - about 60-70 kmh - when it did the apparent declutch/ reclutch thing twice, separated by about half a second. I noticed that each time it did it the 'check engine' light came on momentarily. So I'm beginning to wonder if its possibly an engine problem rather than a gearbox problem.

Other than this the car is running well.

Willem

[WasabiPimpNinja]

I havn't really had a look to see what kind of switch the RR's have, but it could be something in your kickdown switch on the gearbox. If it's shorting out or reading the wrong value it may be try to downshift for you, then realize it doesnt need to and try and re-engage the belts.
Dont have my RAVE cd with me so cant have a look.

[LandyAndy]

As metioned.
If its just had a service,the levels are correct,the seating/seal of the filter needs to be looked at asap.
Goodluck
Andrew

[DT-P38]

Hey Willem, Is it possible that engine electronics are the cause and not the trans? Does the behaviour occur at a set rev point and continue until you back off? Perhaps it feels a little like spark is being interrupted/breaking down? Mine behaved like all of that not too long ago. It turned out to be the crank angle sensor banging on something and trying to eat/destroy itself. Hoo-Roo!

[willem]

I havn't really had a look to see what kind of switch the RR's have, but it could be something in your kickdown switch on the gearbox. If it's shorting out or reading the wrong value it may be try to downshift for you, then realize it doesnt need to and try and re-engage the belts.
Dont have my RAVE cd with me so cant have a look.

Hmmm. Thanks for this. I shall have to check this out.

Willem

[willem]

Hey Willem, Is it possible that engine electronics are the cause and not the trans? Does the behaviour occur at a set rev point and continue until you back off? Perhaps it feels a little like spark is being interrupted/breaking down? Mine behaved like all of that not too long ago. It turned out to be the crank angle sensor banging on something and trying to eat/destroy itself. Hoo-Roo!

Yes, Dave, that possibility is one that I'm thinking about also. The problem *seems* more noticeable on LPG than on petrol. The LPG system in an injection system with its own ECU that piggybacks on the engine ECU.

Willem

[Junosi]

Did you manage to resolve this issue Willem ? Today coming back from Mt Macedon my car was exhibiting similar gearbox symptoms to what you described - with the clutch/declutch thing going on upon acceleration. It was mostly happening from a standing start as I accelerated - every gear change it seemed to briefly lose power every time it shifted. At 70km/h if I put my foot down to make it kickdown it seemed to get all confused and pretty much do nothing until I backed off the gas. It had seemed to have sorted itself out by the time I got back home but it's got me wondering now .... At a guess it seemed an electrical or ECU issue as the engine is faultless and if I manually control the gearbox it is fine also.

edit: Fluid level is fine

[BusinessConnected]

Seems to be the season for Gearbox Errors!!!

I've been playing around getting my LPG Tuned up nicely (finally getting there Junosi) and I was driving around in 1st gear at 60-70km for a minute or so today. (Coasting & Acceelerating ete ete).

Anyhow, as I came to a Stop I got my first ever "Gearbox Error" Message. I figured I'd probably been a naughty boy and overheated the Gearbox so I let it run for a while and all was well again.

Later this evening I turned on Sport Mode, And Tested the Accceleration to the full 5000-5500rpm and as soon as I came to a stop at the lights again, Gearbox Fail... Car Stalls and I'm forced to turn LPG Off and attempt to restart the car.

I'm beginning to wonder whether perhaps my Issues are related to a need for a Battery Replacement, as All Fluids were changed in the last 10,000km. (Trans & Differential).

Here's to hoping I haven't broken something.