Changing DB9 diff oil (Automatic)

[MaverickV12]

Wanted to change the diff oil in my DB9 as tight corners have started to induce a stutter in the diff, like turning a corner and finding it grinding a bit, or shuddering. I had it changed myself about 15 months ago, at a franchise dealer, it made a difference then and thought that it would be the same now.

The official manual says .........



Sealed for life ...... it is not sealed for life, and AM now say change every 2 years. Having said that I just phoned up AM again today (HR Owen) and they said it needs to be changed every 4 years or 40k miles.....umm .....

At 15 months I did not want to change the filter, just the 1.7litres of oil to make sure there was no problem.... little did I know .....

You will need this .....



Incidentally the draper pump worked bril.

The drain bung is here and is a big hex plug ........



The fill bung is here .....



If you have a manual gear box, then you'll find the filling bung on the other side.

I drained the oil and I found this .........



Surprised was not the word ....... I was expecting a little tinge of brown, but to find the oil comes out black was not what I thought would happen.



So I changed the oil with 1.7 litres of clear fresh diff oil, the drive was different and again i did not think that it would make that much of a difference, but it did. I have now ordered a new filter from HR Owen and 3 litres of new diff oil. I will leave the oil as it is for a little while, then change it all in the next couple of weeks. Being gear oil and not engine oil I was expecting to find it the same colour or slightly brown, not burnt and black.

[DB9VolanteDriver]

Well, since the diff is of the limited slip variety, it has clutch packs which release when you are turning tight corners (hence the grabbing/shuddering). As these clutch packs wear the oil gets dirty, unlike the gearbox itself. So not a big surprise.

[SS972]

I run an independant Land Rover workshop and we are changing the diffs, gearboxes and tranfer box oils in all vehicles evry 40 000kms (25 000miles) and I do the same for my DB9.The sealed for life thing is a stupidity.

[MaverickV12]

SS972 said:

I run an independant Land Rover workshop and we are changing the diffs, gearboxes and tranfer box oils in all vehicles evry 40 000kms (25 000miles) and I do the same for my DB9.The sealed for life thing is a stupidity.

When you change the LR oils, is the oil the same black colour? Is it burnt?

[Gibberish]

MaverickV12 said:

...I will leave the oil as it is for a little while, then change it all in the next couple of weeks.

Maverick, when you change the oil again, consider a Kendall LSD type additive as well.

It certainly helps to temper the worst of the juddering.

[Neil1300R]

Give up. Can't spot the headache tablets, where are they in one of the pictures?

[ds2000]

I think I'll be doing this on mine in the coming weeks. While it drives well I can't help but think the diff is growling slightly

[MaverickV12]

Gibberish said:

It certainly helps to temper the worst of the juddering.

When the oil was changed 15 months ago, the change was revolutionary. I am guessing the oil was years old then and never been changed. After 15 months, the oil was still, "ok", but in changing it, again, the change was, "marked", (not revolutionary). I am assumming that when it is changed again with the new filter and the ful 2.4 litres, I am guessing that the diff will run about as best as can be.

Do you think that when the oil is brand new AND with a new filter, are you saying the additive will make a further difference?

[MaverickV12]

ds2000 said:

I think I'll be doing this on mine in the coming weeks. While it drives well I can't help but think the diff is growling slightly

Do you know the last time it was changed? If it has been a while, you may find that you have slowly grown, "used", to the way it feels. In normal driving there is almost no difference, in slow maneuvering there is a big difference and when pulling away from a turning, a huge difference.

[Gibberish]

MaverickV12 said:

...are you saying the additive will make a further difference?

Yes,

mine had the diff oil changed at my last service and without the additive, the noise at full lock and low speed was quite bad.

At the time of it being serviced, I hadn’t realised that I’d need to request its inclusion within the oil change.

My car was promptly returned to have the additive put in and all was well again.

[Genie Chaser]

Maverick, when you change the oil again, consider a Kendall LSD type additive as well.


Don't add a Kendal addative with the oil pictured, as it is already added to that oil. Putting more in I believe can cause damage to the diff assembly.

[MaverickV12]

Gibberish and Geniechaser, this additive I can't seem to find any info on it to read. It seems like other PH'ers have had the same problem ......

http://www.pistonheads.com/gassing/topic.asp?t=110...

Do you have a link where I can read about this additive, if its good ( and if AM are putting it in then I guess it must be) I would like to read about it. There is nothing on eBay and when I put the name in, it only brings up forums.

Thanks in advance .....

[Gibberish]

Genie Chaser said:

...Don't add a Kendal addative with the oil pictured, as it is already added to that oil. Putting more in I believe can cause damage to the diff assembly.

Just curious. Which one of bottles has the additive in it?

[yvr]

Maverick,

More from the colonies... A technician working at an Aston dealership is a regular contributor at 6speedonline and had this to say about transaxle/diff fluids...

The Castrol BOT 270 A is not available in N.A, the "BOT" number is a term they use in the UK..being that we can only order it from Aston, we checked locally with our Castrol rep..our rep advised us the N.A version would be Castrol SynGear 75W90. Only difference is the SynGear does not have the same amount of additive for the diff clutchs, so per Aston there is a additive for this which is the
Kendall Diff Additive..I put in the additive then fill with the Castrol SynGear fluid

For the 1-2 shifting, the fix is to slightly grind the top left corner of the shifter ball holder(grind the plastic only about 1mm)..this allows for a further engagement.

For the DBS/DB9 manual box, same fluid is used Castrol BOT 270 A, or equal which we use Castrol SynGear 75W90 + additive.

For the auto box, Shell ATF M-1375.4 is used by Aston in the UK, we can only get this from Aston..we also service Land Rovers and Jaguars here which all use the ZF auto trans. We asked are hotline if the Land Rover fluid can be used, for it's much easier and faster to get, hotline gave us the O.K for the fluid is the same type. So we use the Land Rover/Jaguar ZF trans fluid for the trans axle and the Castrol SynGear + additive for the Diff.

[Genie Chaser]

Believe that the 704349 pk oil as shown in the picture has the adative pre mixed. May be worth a call to your dealer to confirm this. Have heard excessive adative can cause diff failures.

[Genie Chaser]

Also, the filter in the bottom of the diff, held by 2 x 8mm bolts is a plastic filter, no need for replacement. Just clean out with brake cleaner.

[MaverickV12]

Genie Chaser said:

plastic filter, no need for replacement. Just clean out with brake cleaner.

I was told it was a steel gauze type and its damned expensive at £68.00 plus vat, I have ordered one and will change it later on. Having said that I will take out the old one and look at it, if it is cleanable then I would indeed be foolish to throw it away.

Will email a AM franchise today and try and get an answer about the additive. I can understand the theory with the 6speed forum, but if Gibberish took his car back and AM added an additive (bad English there - sorry), then they must have done so for a reason.

I base the theory on the fact that the designers of the car originally specified, "sealed for life", and this was clearly wrong, ok, at least AM addressed the matter and didn't say, "no its fine", they changed the design. If they changed it, then clearly (amoung many other factors and items all over the car) then the design is a, "work in progress", in that designs are constantly being updated. Indeed this would be spec development.

I'm thinking, original spec was sealed for life, then changed for 40k/4years (HR Owen), others say 20k/2years (Derby Franchise - forgot the name), should we really ignore an oppourtunity to look into the additive issue? When I attended the GenerationAMR open day, they said that they change the gearbox oil after every race, not sure I want to change my diff oil every weekend ........

[ds2000]

MaverickV12 said:

Do you know the last time it was changed? If it has been a while, you may find that you have slowly grown, "used", to the way it feels. In normal driving there is almost no difference, in slow maneuvering there is a big difference and when pulling away from a turning, a huge difference.

I would assume its never been changed. Its very grisly when cold and turning hard left or right out of a junction onto the main road. Not mechanically nasty sounding but to my ear makes me think it needs changing.... will probably do the G/B as well

[millsjq]

Excuse my ignorance, what is a draper pump? And the diff filter, does a Vantage have one, I did not think it did.

[originalgeezer]

If you cannot get Shell Spirax Spirax ASX 75W – 90 oil, fill the differential with Shell SAE 75W-90 oil and
add one bottle of Kendall additive