Sticky Downshift.....

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Saint.V8

Dyed-in-the-wool 100% RR Junkie
Full Member
Odd one....

When braking and the box is downshifting from 2nd to 1st as you come to a halt it is as if the Gearbox isn't 'letting go' similar to if you are coming to a halt in a manual and forgot to press the clutch until the last minute and then the engine revs drop then stutter back to idle again....

It doesn't do it all the time, only occasionally, but once it has done it it will continue to do so until you switch off and it has cooled down for an hour or so!

As I say it is as if the clutch isn't slipping until the engine revs drop then they stutter, the gearbox 'releases' and the revs pick up and back to idle....

Also when braking and you have the windows open you can hear a click from under the car fairly central....not a menacing click, just a mechanical click....doesn't make this click when crawling, only above 10mph or so....

Any clues as I'm stumped.

PS: only starts doing it after a moderate to hefty braking situation i.e. braking downhill to a set of traffic lights....from then on each braking moment to a halt causes it, unless you lift off the brakes a tad to reduce retardation until you come to a halt....

4.4 2003 Vogue on Gas....
 
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Researched a little -

Seems like there was a software update for the L320 Sport and the LR3 Disco to change the shift/throttle torque reduction maps....might give a friendly LR Dealer a call and see what thats about.

Also, reading a few BMW Forums, they seem to point to a MAF issue...one guy on there writes:

Cam shaft sensor or indeed the MAF

Let me guess the hard down shift is when your doing 3-4-5 mph almost coming to a stop? if so watch the RPM the will drop below 500 just when the tranny downshifts.

That is 100% the MAF

Any Comments?
 
More Research - found this might help someone...(I know it says 6spd, but technically they are the same thing I should imagine)

Will try the 'on petrol' journey tomorrow and report back.
 

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Did the journey to work on Petrol this morning and tried to recreate the scenario...

Didn't seem to do the harsh downshift, and I tried to initiate it with some moderate to heavy braking to a complete halt at a few traffic lights - but no avail....

As I said it only does it occasionally, so maybe it is playing ball today...

I did notice a couple of times the revs dropping low as coming to a halt, but the pickup back to idle wasn't anywhere near as harsh as it is on Gas...

Will try the journey home this evening on petrol too, as it seems more prone to do it on the way home - will report back.
 
Well drove home and the harsh downshift, jerkyness coming to halt happened twice on the way home....

I was running on petrol so seems to happen on both fuels....

I will check connections to the MAF, and also call my friendly LR dealer and ask about the software update....

Anyone any clues??

Rewmer - intrigued by your request to test it with petrol, could you elaborate?
 
It's only that mine does exactly the same on gas only, and I know the calibration is out on my lpg system oh well. If you can get some live data from your maf, I have some readings from a known good system.
 
Could be the gearbox fluid,gearbox fluid cooler, or radiator. I had my gearbox cooler changed and the fluid, the problem went away.
Diagnosed with a laser thermostat, measured the sump pan temp underneath the car and it was well over 126 (fluid well cooked). It's now about 95c after a drive through traffic. Oddly I was not getting any fault messages on the dash. Hope this helps.;)
 
Half the problems with range rovers and other 4x4 petrol powered vehicles.
Is that people buy/convert them to run on LPG!
LPG aftermarket convertions never, i repeat NEVER work for long without fooking something up!

A v8 petrol is a v8 petrol!
Saint!
I would sell the car asap, i think it may be one of those cars mate that just has issues!
And go out and buy a Td6 vogue.
I get 30 to the gallon mate and after a remap it has loads of grunt too!

Ive bin there done that with LPG convertions and now would not touch one with a very large barge pole!
Sorry for dissing your cars guys.
I just had a load of realy bad issues with an LPG convertion on a Grand Cherokee.
It nearly cost me my life when the air box Exploded!
Killing the Electrics and engine at 75mph on the motorway!
Try controlling a car thats on fire! No power steering, no visibility, in fast lane of m1 in rush hour!
LPG
NO WAY
Lol
 
Half the problems with range rovers and other 4x4 petrol powered vehicles.
Is that people buy/convert them to run on LPG!
LPG aftermarket convertions never, i repeat NEVER work for long without fooking something up!

A v8 petrol is a v8 petrol!
Saint!
I would sell the car asap, i think it may be one of those cars mate that just has issues!
And go out and buy a Td6 vogue.
I get 30 to the gallon mate and after a remap it has loads of grunt too!

Ive bin there done that with LPG convertions and now would not touch one with a very large barge pole!
Sorry for dissing your cars guys.
I just had a load of realy bad issues with an LPG convertion on a Grand Cherokee.
It nearly cost me my life when the air box Exploded!
Killing the Electrics and engine at 75mph on the motorway!
Try controlling a car thats on fire! No power steering, no visibility, in fast lane of m1 in rush hour!
LPG
NO WAY
Lol

Well mine's been fine for ages (and never had an lpg problem). Sounds like you just had a crap conversion - cheapo single point? Must have been to blow up the air box.
 
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