Hi everybody, I am hoping somebody can shine a light on a problem I am having on my 2005 TD6.
I have searched the forum back and forth and can not find anything similar enough to compare issues but that's not to say some of you RR geniuses on here will not be able to point me in the right direction.
12 months ago I had the dreaded but expected (150000 miles clocked up) gearbox failure, only a couple of days warning with 3 episodes of slight rumble at 30 mph when accelerating then total failure. No other driving or engine issues up to that point.
Car went in to reputable gearbox centre who replaces these L322 TD6 boxes at a rate of about one a week.
Total refurb done and 12 month warranty given, great I thought. However in the first week I noticed the car was misbehaving when cruising down a slight decline with foot off the accelerator, it would drop down a gear then a second later back up and then continue to go up and down until I levelled out. Then a few days later it would do the same on flat ground when lifting off the gas.
I returned to garage who immediately inspected the box but could find nothing wrong. I put it down to a possibility it was the adaptive learning of the new gearbox.
It gradually got worse and the gearbox centre suggested I take it to a general garage to check for restrictions in power such as egr valve, injectors etc as it could be a fuel starvation problem.
Did this and had EGr valve cleaned and everything checked. All ok
Returned to gearbox centre and explained it was still the same so they rebuilt me a new gearbox from scratch.
Whilst in the garage the car would not start and needed a secondary fuel pump. This could be partially why the car was going up and down gears.
I got the car back and it has never driven the same since. Not terrible to be honest but can often search for gears and sometimes holds onto gears.
Just lately it has developed a different gearbox fault ( I am guessing gearbox but this is where I need help )
When leaving work in the evening and the car is cold it gets up through the gears fine, about 5th gear at 30-35mph but then when I gently accelerate it seems unhappy, it judders but not in a gearbox way but as it would having a manual car in too high a gear, if I kick down it is fine. Also I have had a couple of occasions when I have been in 5th gear at around 35mph, lifted off the gas to slow down and the car has stayed in top gear too long and when I go to gently accelerate it is in the wrong gear for that speed.
I am booked back into the gearbox centre for him to check things over to rule out gearbox issues.
But I do not know where to start first with solving the problem if it is the engine
I now feel I have a great gearbox connected to a not so great engine. The engine although high mileage has been exceptionally well maintained and has wanted for nothing during my ownership, I never scrimp on the repairs and maintenance.
Rather than start changing transfer box ecu and gear selectors etc I thought I would ask you guys if you might have a good idea what it could be. I must mention since getting the car back 12 months ago I have always had a judder at around 50 mph in 5th gear when accelerating, that could be 22 inch wheels, although the tyre size gives it the same rolling road radius as normal RR alloys.
Could this be an injector problem or the in tank lift pump problem?
I would be grateful for any help offered.
Thank you in advance.

Hey,

Sorry to hear about that issue.

Did the gearbox place flash/reset your gearbox ECU when you got it rebuild the first time?

My understanding is that they need to reset it so it will recalibrate as you begin to drive it again. All new internals etc combined with your driving style. This might leave it a bit weird for a couple hundred miles.

If they didn't do it then the gearbox could be searching for a new gear when it shouldn't have to and is creating a bumpy ride.

The td6 is a pretty solid under-stressed unit.

Hi, thanks for the reply.
The reset was done and I did expect a bit of a different drive for the first couple of thousand miles whilst the box was learning, however it has been in for 11000 miles now and still isn’t right ☹️

Have you tried doing the adaptive gear reset routine? There's a thread on the forum about it, which involves inserting the key into the ignition, turning the key to position II then depressing the accelerator, etc. Can't remember who on the forum had posted about it, but it's supposed to reset the ecu to default driving style which then 'learns' your driving.
It may be worth a search, and a try?

Hi mate, yes I’ve tried it a couple of times in the last 5 months but it hasn’t seemed to make difference unfortunately

have you got any decent diagnostics to plug it into ?
It could be injectors or wiring causing the issue but i would expect a fault to be logged and the injector looms are very well known to fail as i found out with the TD6 i am currently nursing for somebody.
i would read the codes but if you dont get any issue you could try removing the top engine covers and gently touching the injector loom wires but they are fragile so you may create a problem you didn't already have.
i could tell by using my faultmate and reading the fuel compensation of each cylinder whilst touching the loom but my fault was at idle and caused judder when moving away off idle and there was a cylinder 3 fault logged.
It would also be worth asking if they tested the valve body in the gearbox and had the sonnax upgrade done if it was required which is the route of the GM box fail.
You can remove the valve body and have them tested at valvebodies.co.uk or something like that and they will also carry out the upgrade but have a search of RRPhil's posts on the subject as he hof course has much more knowledge on the subject but again i would be reading the codes with a gap tool or something similar.

Hi, thanks for your reply. The second gearbox was built from new. The first one that they rebuilt was eventually put in another customers car, such was the garages confidence that it wasn’t a gearbox issue, and they’ve never seen that car again. So I’m sure the valve body etc is ok, although when I take it back they are going to strip and check everything. My other suspicion is as you say, injector problem and now the loom after you have mentioned that. The gearbox garage are going to plug it in to check for faults but if their equipment is basic I will then take it to somebody with an all comms system.
The main objective first is to rule out the box, valve body, solanoids etc.
I hoped somebody might have read this and went ahhh, that’s exactly what happened to mine and this is the fault you are looking for but with all the things that it could be I knew I was grasping at straws 😬
Thank you for your help though it is very much appreciated 👍🏼

Somebody on landyzone chased a vibration problem and had the prop rebuilt and engine mounts i think and torque converter i think and ended up being an injector after a long time and expense of trying to solve it

Thanks mate, I’m definitely going to Pursue the injector issue. Thank you

No bother.
There you go - if you have a free week, have a read

https://www.landyzone.co.uk/land-rover/pro...on.302806/

Thanks buddy, all help is greatly appreciated. Have a good weekend

Did you ever get to the bottom of this.? Think I'm having the same issue