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Discussion Starter #1
I have 2008 Range Rover Full-Size Supercharged with approximately 127K. The transmission fluid has been flushed every 50K and was last performed at 100K. There are no leaks and ZF fluid was used.

Recently I have been experiencing a slight transmission slip at slow speeds after coasting and re-engaging the gas pedal, e.g. coasting into a city block turn and then engaging the gas to accelerate out of the turn; at a stop light to accelerate on go. It slips for a second and then engages. I define slipping as engaging the gas pedal the revs go up but it's clear the transmission isn't engaged. When the transmission does engage after the slip, there is no banging or odd feel, it just engages. The issue is occasional and doesn't happen on every drive. It's more likely to occur when the car has sat overnight and it doesn't happen at high speeds.

I have a sophisticated diagnostic computer and there are no trouble codes.

Lastly, I've noticed that if I have the gear selector on Sport Mode, I haven't had any slipping.

Thoughts on what I should be looking for?
 

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I have 2008 Range Rover Full-Size Supercharged with approximately 127K. The transmission fluid has been flushed every 50K and was last performed at 100K. There are no leaks and ZF fluid was used.

Recently I have been experiencing a slight transmission slip at slow speeds after coasting and re-engaging the gas pedal, e.g. coasting into a city block turn and then engaging the gas to accelerate out of the turn; at a stop light to accelerate on go. It slips for a second and then engages. I define slipping as engaging the gas pedal the revs go up but it's clear the transmission isn't engaged. When the transmission does engage after the slip, there is no banging or odd feel, it just engages. The issue is occasional and doesn't happen on every drive. It's more likely to occur when the car has sat overnight and it doesn't happen at high speeds.

I have a sophisticated diagnostic computer and there are no trouble codes.

Lastly, I've noticed that if I have the gear selector on Sport Mode, I haven't had any slipping.

Thoughts on what I should be looking for?
There are a ton of posts on this issue. Some call it "tip in thump" others call it "roll out 2-1 kickdown" etc. What is happening is on no throttle deceleration like coming to a stop, the transmission does not complete the shift from second to first before the car stops. Then you are applying the throttle again when the transmission is not yet engaged in first. The revs come up a little and then it finally hits first gear at high revs the drive train thumps hard like you dropped it in gear from neutral. Sometimes brutally hard if you really step on the gas quick. It is a very common problem with a number of different things that people have tried that fix it at least temporarily so there are a lot of opinions out there. People have had success with fluid changes, internal seal replacements, shift solenoid replacements, entire valve body replacements, transmission adaptation resetting and software reflashes. I am convinced it could be fixed permanently with software but there are no aftermarket software modification programs available anywhere. The only software that can be installed is the latest version of the factory program that does NOT address the actual issue. The fact it doesn't clunk on your car when you use sport mode and the fact you can manually downshift from 2-1 before you stop, say at 15mph, it will NEVER CLUNK proves that the "learned" software program is just not downshifting soon enough when it is in control. My car did it regularly, had a complete valve body replacement and it went away for 6 months, then slowly developed into a full fledged thump again as the transmission "adapted" to the driving style. I've modified my driving style to come to a complete stop or manually downshift coming to a stop sign and avoid the clunk altogether but it's nonsense that there is no simple programming mod that can set the 2-1 no throttle downshift to 15mph or so like every other normal transmission does. Do some forum searching and contact RRphil with your exact symptoms for his advice on this. He knows more about these transmissions than anyone I've seen yet.
 

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Discussion Starter #3
There are a ton of posts on this issue. Some call it "tip in thump" others call it "roll out 2-1 kickdown" etc. ... The fact it doesn't clunk on your car when you use sport mode and the fact you can manually downshift from 2-1 before you stop, say at 15mph, it will NEVER CLUNK proves that the "learned" software program is just not downshifting soon enough when it is in control.
Thanks this is very helpful. It also reinforces that it's more likely a software issue rather than a mechanical issue since it works in Sport without issue. I was going to clear the adaptations and redo the process; however, a lot scary discussions about this. Additionally, if I cleared the adaptations, I would need to figure out where exactly I would do the relearn without getting into an accident.
 

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Thanks this is very helpful. It also reinforces that it's more likely a software issue rather than a mechanical issue since it works in Sport without issue. I was going to clear the adaptations and redo the process; however, a lot scary discussions about this. Additionally, if I cleared the adaptations, I would need to figure out where exactly I would do the relearn without getting into an accident.
Yeah, the "re-learn" procedure is completely absurd. If you go thru the whole process you quickly realize no shop in any real city is going to be able to perform it properly given daily traffic considerations. It's especially hard to find a dead chicken to swing over your head after you spin around three times and face to the North.
 

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Discussion Starter #5
While I do not know if this was the cause of the "tip in thump" problem I was having; however, I noticed while driving today the gear selector would very quickly jump out of drive into neutral and back into drive whenever there was the slightest inertia in the car, e.g. braking, taking corners, etc. I just happened to notice this because I was looking down near the gear shifter and saw the Drive "D" light flicker out. "N" never illuminated because the "D" would come on a split second after it flickered off.

I did some more tests while stationary and a slight touch to the shifter would take it out of drive.

This problem points directly to the transmission linkage cable. I sprayed linkage with WD-40 to clean it up, followed by silicon spray. The jumping out of drive was solved. I haven't done enough driving after cleaning up the linkage to determine if my "tip in thump" symptoms are separate from the linkage issue - however, the transmission/engine feel of jumping in and out of drive seems to be similar to the "tip in thump" symptoms.
 

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Discussion Starter #6
I've taken the vehicle for 4 drives since cleaning and lubricating the linkage cable and the slight transmission slipping when accelerating out of a stop and while taking turns is now gone. It would never have occurred to me that the transmission gear selector was slightly jumping in and out of drive.
 

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I've taken the vehicle for 4 drives since cleaning and lubricating the linkage cable and the slight transmission slipping when accelerating out of a stop and while taking turns is now gone. It would never have occurred to me that the transmission gear selector was slightly jumping in and out of drive.
I've taken the vehicle for 4 drives since cleaning and lubricating the linkage cable and the slight transmission slipping when accelerating out of a stop and while taking turns is now gone. It would never have occurred to me that the transmission gear selector was slightly jumping in and out of drive.
That's a completely different issue than the "tip in thump". Never heard of the shifter actually moving? Wow.
 

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Discussion Starter #8
That's a completely different issue than the "tip in thump". Never heard of the shifter actually moving? Wow.
This post answered by RRPhil was my exact problem. The initial post describes a similar slipping out of transmission issue.
 
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