Hi,

I know this has been discussed to death, but thought I'd add the IID codes also in this one.

Got the limited gears message after about 10 minutes of driving. Comes with the obligatory F on dashboard. Can be cleared temporarily after clearing codes.

My amber suspension light is also on and only disappears for a bit after I also clear the faults.

Any ideas ? hopefully the two are connected as I know how tempramental these can be, and really hope it's not a fecked gearbox.

I have listed the codes from IID Tool:


Suspension

C1A20-64 (AF) Pressure increases too slow when filling reservoir - Algorithm based failure - signal plausibility failure
( on 26-07-2020 20:59:46 at 187638 km )
Transmission

P0730-00 (6D) Incorrect gear ratio
( on 26-07-2020 21:15:33 at 187638 km )
P0782-64 (ED) 2-3 shift - Algorithm based failure - signal plausibility failure
( on 28-07-2020 18:13:22 at 187646 km )
Vehicle Dynamic

U0132-87 (2B) Lost communication with ride level control module - Bus signal/message failure - missing a message
( on 26-07-2020 20:59:46 at 187638 km )
Ventilation

B1B78-84 (2F) System pressure - Bus signal/message failure - signal is below allowable range
( on 26-07-2020 15:23:45 at 187638 km )


 RRS 2.7 HSE Stornoway Grey
P38 4.6 HSE V8

Well you need a replacement gearbox
Probably A new suspension compressor or tank
And the air con filling.

Thanks for the feedback Andy

Regarding the gearbox replacement... I'm just trying to establish it's 100% the gearbox that needs replacing, I know the IID Tool doesn't lie so further road testing done, and yes the gears feel like they are slipping i.e. if I put the foot down it does drive for a bit but then it's like it's revving in the gear, and ten minutes later I get the F on dash.

Also, is it possibly a flywheel replacement ? or is it just worth changing the full gearbox. And as for the transfer case/box, where does that come into the equation ?

I'm just trying to gauge what's involved in changing the gearbox. We've done an engine replacement a couple of years ago on this, whereby you and others on this forum gave me much valuable information on the way to fixing the engine, so am merely looking at this point to find out what I may have in store if tackling this myself.

Any information, or links to posts whereby someone has been down a similar route would be gratefully accepted.

 RRS 2.7 HSE Stornoway Grey
P38 4.6 HSE V8

Yeah it's probably the gearbox.

You could try driving it in manual mode.
You may find one gear doesn't pull very well.
Obviously if you find out which gear is trouble some you can avoid using that for a bit while your source a replacement.

The main issue with the gearbox is the weight. Though see video below of the method one person used on a similar gearbox. (but 8 spd)

The transfer box is bolted onto the end, so I assume requires removal first. (yeah it does for clearance apparently)

The torque convertor is the other issue you need to consider replacing. (between gearbox and engine - looks like a big donut) If you experience juddering (cattle grid) or the rev counter going up and down by a small amount (when at a constant speed) are the signs this needs replacement. Lots of videos of BMW revcounters on youtube to give examples.



Last edited by Andy K on Wed Aug 12 2020 1:23pm. Edited 1 time in total

Nice one Andy thanks for that, might be something I could do.

Yes you're right, it drives better for a wee bit longer in manual, and I've also got the (cattle grid) thing going on.

I'd be looking at gambling on a used gearbox, theres loads online that include the torque converter and transfer box.

I'd just be looking at finding out all the tricks and tips of this change, i.e. is it better to drop the full thing down or do it in sections?

Feel free to all add your tuppence worth.

 RRS 2.7 HSE Stornoway Grey
P38 4.6 HSE V8

I've not done it yet, so not a lot to add ATM

DerrekL wrote:

Nice one Andy thanks for that, might be something I could do.

Yes you're right, it drives better for a wee bit longer in manual, and I've also got the (cattle grid) thing going on.

I'd be looking at gambling on a used gearbox, theres loads online that include the torque converter and transfer box.

I'd just be looking at finding out all the tricks and tips of this change, i.e. is it better to drop the full thing down or do it in sections?

Feel free to all add your tuppence worth.

Thanks Andy, if you find anything else, please let me know...

Thanks for the input RRSTDV8, OK you've got my attention... replacing the torque convertor clutch maybe a solid choice for me here I hear you say... I'll obviously have a look into what's involved in replacing the TC clutch only, but if you have any experience in doing this kind of job then I would appreciate all you have on this.

My newbie questions probably start with these:

1) Can the TC be taken out without disturbing the gearbox or does everything need to come off anyways? i.e. does the full gearbox need to be dropped ?

2) When you say replace the TC Clutch, would it be easier/better to just replace the whole TC unit rather than the TC Clutch itself ?


Yes agreed, purchasing a "scrapyard" gearbox wouldn't the best solution

Any other info would be greatly appreciated, especially with my symptoms described at the top of this post, and replacing only the Torque Convertor.

 RRS 2.7 HSE Stornoway Grey
P38 4.6 HSE V8

Gearbox needs to come out to replace TC as it's in the middle between engine and gearbox

The TC issue is
Slightly less important than your gearbox issue I would say.

You may as well replace both at the same time and then see what you end up with.

I believe modified TCs are available which should last longer

I don’t think a clutch is a separate item : edit apparently it is!

Last edited by Andy K on Fri Aug 07 2020 2:03pm. Edited 2 times in total

The TC clutch is within the TC housing so you get a new one when you replace the TC.

The TC is between the engine and gearbox so you'd need to remove the gearbox to get to it. That means disconnecting the rear prop shaft, front prop shaft, removing the transfer box and then dropping the gearbox.

Search for user Naks hereabouts. In his signature is a link to the workshop manual. That would seem to be a sensible rear if you're doing it yourself.

I'd be tempted to get the gearbox reconditioned by a suitable company. Then you'll get everything that needs replacing replaced and you end up with a gearbox that's as good as new without spending out for a new unit. 2012 SDV6 - it's missing a couple of cylinders
2008 TDV8 - it was a labour of love and is much missed

Superb!! short and to the point, just how it should be, thanks again guys

So in a nutshell... my options:

1) Replace TC only and take a massive/stupid ? gamble all will be OK.

2) Replace full gearbox which includes TC and Transfer box with a "scrapyard" lump. Nearly sensible gamble.

3) Get gearbox reconditioned. Should work as new. No gamble.


anymore for anymore ?

 RRS 2.7 HSE Stornoway Grey
P38 4.6 HSE V8

New gearbox time

2nd hand can be a big gamble

You may as well use your existing transfer box as it’s known good.

Yeah a used one is a gamble. Your
Saving £1000? But if it doesn’t work and you can get a
Refund I guess its ok as long as you get it fitted quick.
I noticed Ebay have reduced the return notification to 10 days?
It is different for business sellers?

I would be interested in your sums. (Not to critique them)

Thanks for all the info guys, at least now I have an idea of what route to go down, and thanks for chipping in Mikey, much appreciated

I'll keep yous posted on my travels with this one...

 RRS 2.7 HSE Stornoway Grey
P38 4.6 HSE V8

Ok plan is to drop the gearbox at least.

Few things I'm not sure about...

Does it matter what position the gear selector is in, Park, Neutral or doesn't it matter ?

Do I need to touch the exhaust system ?

Does starter motor need to come off?

Any other nuances i could be better off knowing about before I get stuck in ?

 RRS 2.7 HSE Stornoway Grey
P38 4.6 HSE V8