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.

[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?

[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.

[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 .....

[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 ........

[MaverickV12]

ds2000 said:

will probably do the G/B as well

I changed the Auto oil when I changed the diff oil 15 months ago. The diff oil is obviously the subject of this thread, but the auto oil was not burnt, and came out almost as nice as the stuff going in. If you are changing this yourself, then apparently (what I am told) is that you drain off what you can, say about 3 litres. Then refil with 3 litres of new oil, run the car and mix the oil. Then drain 3 litres and refil and run, etc etc. You can take the car to a specialist gearbox place who (so I'm told) will be able to drain everything in one go, but I am told it is a specialist job to do this.

millsjq said:

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

3200GT is quite right. I used the pump to insert the oil because the fill bung is up on the side of the diff. The drain bung is right at the bottom and was easy to drain (other than I had to get a big hex bolt). The V8 uses the same diff and gearbox (whether manual or auto), if you have a manual the fill bung would be on the other side.

originalgeezer said:

fill the differential with Shell SAE 75W-90 oil and add one bottle of Kendall additive

I am all ears about the Kendall additive, but can't find any info on it, let alone where to get it.

[MaverickV12]

SS972 said:

80 000kms with regular oil changes they are good for 250 000kms

I can understand the, "sealed for life", is not correct, but I did not think that an Auto Box would fail at 1/3 of its life span

SS972 said:

additives for its LSD and they are quite good,if intrested I can find the ref.

please .....

[MaverickV12]

SS972 said:

Jeep additive ref is PN 43118060AB, two needed for a diff containing 2 liters.

Thanks, I will research what this is.

I got sent these today ......



I got them from Aston directly,

I also bought this ......



The filter is a gauze and not an actual filter, and looking at the new one, I think the old one can be washed out.