S

suk115

New Member
Hi I am new to this forum and need some help. I have a Range Rover (L322) Vogue 4.2 V8 supercharged 2006.

When I am driving the gears change at the normal rpms, however for higher speeds I have to drive faster before the rpms drop back down to the normal 2000's. So basically now when I get to 70mph the rpm counter does not drop down which it normally does, now it stays in the 3000's. It's only when I get to 75mph that the rpm counter drops back down to its normal 2000's. I tested this several times and noticed that only when getting to 75mph would the rpms settle. It's as if the threshold for the gear to change has increased. No error messages are coming up on the dash.

Incidentally today I had a new tyre fitted on the front right of the car as I got a nail in it and the problem above has happened since this. I can't see how this would have anything to do with it but it may just be one of them coincidences
 
Firstly wecome, secondly you need to change both front tyres at the same time uneven wear isn't good on a 4x4 1 tyre worn 1 nrew not good may solve it may not but like you say odd as it happened only after changing the tyre
 
The transmission controller inhibits shifts while cornering to avoid ‘unbalancing’ the vehicle. It decides this by comparing the left and right wheel speeds. Maybe your new tyre has a different rolling radius to the rest? Is it the right size? You wouldn’t expect the 6mm radius difference between new & worn to trigger this, though. Another possibility - inhibited upshifts are often caused by the transmission fluid overheating.

Phil
 
Thanks for your replies, much appreciated. I have further inspected the tyres and the following are the numbers on them:-

Original tyres on the car: R255 / 50 R20 109 V
The new used one: R255 / 50 R20 109 Y

Therefore there is a difference with the tyre. I did a bit of reading and have found that:

R255 is the width
50 is the profile
R20 is the size
V is the speed

Therefore I guess the V and Y could possibly make a difference. I'm assuming now my problem must be happening due to different rotational speeds and possibly affecting the gear change? I really do hope it is as simple as this. It does make partial sense as the lower gears change fine but when getting faster app 65-70 the gear isn't until 75 is reached suggesting needs more rotations or something (I'm really guessing now). I will let you know how I get when I get the tyre changed.

Silly question but as it is with the tyres that are on am I doing damage to the car, someone mentioned something about differentials?
 
Your tyres are the same diameter bar the wear, 255 is 255 mm wide and the 50 is the wall depth as in 50% of the width, the V and Y is the speed rating as in how fast you can safely travel at with that specification of tyre.
A different diameter tyre to the rest is in theory causing the differentials to constantly compensate which is why it is recommended to not have an odd tyre so most at least change both on the same axle
 
Nah, Y just means it was tested to a higher speed rating or somesuch. More expensive!

Important parts are the others: the R20, the R255 and 50.

Don't know anything about the L322. Does it get its speed from sensors on the hubs? Have they knocked one slightly?
 
holidaychicken said:
Your tyres are the same diameter bar the wear, 255 is 255 mm wide and the 50 is the wall depth as in 50% of the width, the V and Y is the speed rating as in how fast you can safely travel at with that specification of tyre.
A different diameter tyre to the rest is in theory causing the differentials to constantly compensate which is why it is recommended to not have an odd tyre so most at least change both on the same axle
Click to expand...

How sensitive is it? Would it pick up different pressures? I've had a tyre done before and got back to discover it was inflated to 50psi!
 
So front tyres been changed to exact same ones, no change to the problem though:-(. The car drives well and the gear changes are smooth and appropriate. It's only when it changes at what would be about 4th or 5th that you have to get the speed at 75mph before the rev counter drops to normal levels. It can't be a fuse I guess otherwise the problem would occur at all gears, I don't think it's a setting in the car. It's as if the gear at that level turns into sports mode or something and just for that one bit in transmission. If anyone has any other ideas it would be much appreciated. It's just so frustrating that the car is working well but this snag is really annoying. I would think if the rpm didn't bother dropping down at all then there was a problem with transmission but it does but the threshold for speed is higher. It it transmission oil or something like that- does that even exist? I agree with 'Grrrrr', L322 is a space age mystery!
 
Sounds like a sticking valve to me, a slipping clutch would slip till you eased off the throttle, wouldnt it?
 
Yes I understand that, I was trying to explain that I thought a sticking valve would stop the clutch biting properly rather than a worn clutch slipping all the time if you can follow my drift
 
I dont know about the L322 auto box but on the P38 changes at the wrong speed can be related to the ECU temp sender on the engine and also the crank sensor .
 
Interestingly if I put the gear into sports mode and drive the car using 'manual commandshift gear selection' if I shift the gears up and down manually they change exactly where I want them to and respond very well. It's making me think that some sensor of some sort is to blame in full auto if not changing gear 5 to 6 automatically unless hitting 75mph? But why only at this gear change is confusing.
 
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