Hey folks, seek seom help over here as am stuck.
I have an 06 DB9 volante that recently has this problem. The car shudders heavily when I turn either left or right but is on when I go straight. This happens at low and high speeds. Could this be due to the differential?

 

Sounds possible, has the fluid been replaced..if it has, was the additive added to teh gear oil?

The diff is a clutch setup, wrong lube, ages lube, lacking additive..you will experience shuddering in corners, mainly at full lock.

If the vehicle is high mileage or has seen a large amount of track use, the clutchs can be worn out and need to be replaced..

First diagnose would be to inspect the fluid and see the state of it, if no concern with fluid9looks new), check the torque of the clutchs by turning the wheel while 1 wheel is locked..if torque is ok and gear oil showed no signs of abnormal wear..replaced fluid with correct grade and add bottle of additive for LSD's(you would replace the gear oil to verify the correct grade is inside, there's no way of knowning the grade previously inside if it had been replaced by someone other than yourself)..

 

Hey Irish, thanks for the feedback. The car shudders even at a slight turn. I assume that the differential oil and transmission oil is the same thins? Car has about 13k miles on it. Was told by Aston that the oil used is
"The transmission oils is Jaguar, part C2C 8432, I think when totally empty the system takes about 13 litres." Do I need to add additional LSD oil inside?

I plan to do the following:
1. Do a full transmission oil change (I get the occasional GEAR BOX FAULT light on and off)
2. Add the LSD oil if I need to

Don't know how much the oil change will do but worth a try I guess..

 

If your comparing to Jag, I assume your DB9 is a automatic?

The auto trans is a 6 speed ZF 6HP26 automatic transmission and torque
converter, the Jag and Land Rover fluid can be used..Aston's fluid can be bought through a Aston dealer(the fluid from Aston is Shell ATF M-1375.4), I remember hearing on a training course, bands are different in the Aston ZF trans for high torque applications, so Aston spec fluid(Shell ATF M-1375.4) is recommended for best driveability)..I myself have never compared the data specs of the Jag and Aston fluids..both fluids though are campatible with there ZF trans and..hehe do spell both like Cat **** though..

The diff is not the same fluid as the trans, both units do not share the same fluid, both units are closed off from each other..all VH platform Aston's use
Shell Spirax ASX 75W-90, which already has the additive inside. In my area we cannot get Shell, only Mobile 1 is available, so a
SAE 75W-90 plus the Kendall additive(Aston supplied part) meets and exceeds standards..

The auto ZF trans takes 10L, + 1.6L in the cooling system so 11.6L total and the diff takes 1.7L, + 0.7L in cooling system so 2.4L total. You won't be able to take all the oil out of the cooling system, long as you get the amount listed from each unit..you'll be good to go

 

Yea the diff and trans are two parts in the transmission. There are also two different fluids. First you state the shudder which is the more likely fault of the diff. Early DB9's had a issue with this and the additive was the fix. Then we start talking trans, lets make sure you are in the right area first.

 

My DB9 is a automatic.
Will replace the trans fluid with Shell ATF M-1375.4. (Red Cat **** )

I will try to get my hands on Shell Spirax ASX 75W-90 and replace the diff fluid.

Hope that by replacing these both, the shuddering should stop though am not certain how much damage the diff already has.. Fingers crossed..

 

You will get some shudder after the fluid replacement of the diff, it will just take driving, mainly cornering in say a parking lot at near full steering lock.. doesn't have to be fast, just to coat the clutch plates with the new gear oil..then the shuddering will reduce and possibly be deleted

 

The trans fluid is not red is this car, its gold.
I would not even change the transmission fluid, change the diff first then see what happens.

 

Don't know why you keep wanting to mess with the transmission oil, you've only done 13k miles, ZF recommend the transmission oil is changed at 100,00 km (62k miles). They have found that oil changes are the main cause of premature failure, i.e. there is more risk changing the oil than leaving the oil as it is.

Sounds like you need to fix the back axle as irish07 has suggested. If you want to change some more oil, do the engine, it won't fix the back axle problem, but would be safer than changing the transmission oil.

 

There is a lot of mixed information on transmission fluid intervals. Some manufactures set it at "filled for life" and some have certain mileage to service.

The Aston ZF DB9 trans is "filled for life" ..I myself have seen the out come of "filled for life" transmission fluid after 100,000km..some are clean and some are just "WOW WTF IS THIS SLUDGE"..

I myself do not follow the "filled for life" routine because of what I've seen*(this is my opinion)..at low mileage I wouldn't change the trans fluid unless slipping was present or gear changes were unnormal. I would change the fluid anywhere between 60,000-100,000km, not before..there is no damage changing before..just it's a waste cause there is no combustion and the fluid is perfectly fine..(unless this is some GT4 car and it's life is track only then forget all that I'm stating..lol)

If this was my car with the same concerns and I tracked it the odd weekend..diff fluid change with correct oil as stated above in previous post would be done..I'd also "check" the trans fluid level, which might require 1-2L..I don't know why but ZF trans like to consume it somewhere..Land Rover, Jaguar, Aston Martin..etc same results..it gets hungry I guess and stores it away with no leaks..VOODOO

I would also change the brake fluid if it has not been done in the last 12months..V12's are every 12 months and V8's are every 2 years..all under normal driving conditions

If the coolant has not been replaced in 5 years, I would also change the coolant..Aston spec is every 5 years or 160,000km

And engine oil, just follow your intervals..if your due..change it

 

I think that ZF was finding that people were letting grit fall into the transmission whilst changing the oil and the grit was generating the premature failures (and potentially causing some of the sludge that you've seen?)

They reasoned that it was better to leave it as it left the factory, rather than risk putting grit in there. So, if the job is professionally done by somone that knew what they are doing, and cares about what they do, then its very low risk, but ...

 

Just did the differential oil change this morning and what an amazing difference.
Absolutely no more shuddering now. Used Castrol 75w-90 synthetic for LSD application as couldn't get shell here. When the mechanic drained the old diff oil, it was black and dirty and only 1L came out. He put in nearly 3L of new oil. There was no apparent leak. Not sure what happened to the old oil.. just vanished..

 

Had the same problem. Changed diff oil with Shell Spirax 75w-90. For two days of driving after oil change the shuddering has gone for almost 90%. Did not believe to results. Thank You very much irish07.

 

So i dont have to worry about thie "NEW" slight vibration i have when i turn.? it just started.
only 24,000KM (14,912 miles)
not many miles but its a 2006. could the diff oil be old? maybe just an additive to see ?
never seen a diff additive here.