XJ8/XK8 & XJR/XKR gearbox oil change

[black1]

thanks mate will get my xk8 in for an oil change as well

[GavinPearson]

robocop said:

Jaguar steve said:

.... Perhaps you could use a normal Dexron 3 spec oil instead?

Thats exactly what my G'box specialist recommended. The original stuff was just designed to last so much longer so they could sell it as a "sealed for life specification" - when in fact that probably really means a few years ( or at least until the warranty had expired! ) If you think about the physics of it all, the oil will be very 'used' after 10years

Mine is a 11yr old XK8 with 92k mls. Just had a G'box service done on it by BK Transmissions, Andover and as BK says, Dexron III is what ZF put in in other configurations. He says it will good for about 5 years. Having seen the state of the filter, I shall certainly be doing this as regular maintenenace from now on. The Box was as smooth as ever with Dexron III and in fact, the stationary changes into D and R were much improved.

No! No! No! No! No!

You DO NOT want to use Dexron III.

Just because ZF used it in the older transmissions, it doesn't mean it is good for use in a 5HP24, and the fluid characteristics are very different to those of Esso LT71141. That's at a microslip level, governing the way the clutches engage the and affecting the control system for the clutches.

When you look at the money you save on the oil, versus the potential damage it will do to the transmission (or the shorteneing of trans life) I'd say it just isn't worth it.

You can of course argue to the contrary, but as somebody involved in the design and sign off of the transmission, I'd advise you as strongly as I can to use OE spec materials.

[sliced bread]

That certainly bears out what I was told by ZF(UK) when I phoned them. Their response to my query (about Dexron 6) was that Esso LT formed part of the design parameters of the XK8 box and only that fluid should be used. The chap said he'd never heard of Dexron 6.

[black1]

gavin im off to the us in 3 weeks can you tell me the best oil for the job and how much i need ?

then i can fill my suitcase up with it !

[robocop]

GavinPearson said:

No! No! No! No! No!

You DO NOT want to use Dexron III.

Great, looks like I have been given duff gen

Thanks for the advice Gavin, I will get it changed back. Can I still drive the car?.. are you saying long term it will do damage?

Edited by robocop on Monday 4th February 21:49

[CHJ]

I have had my XJR gearbox oil changed as a precaution recently at 80k miles, but never having had a car with a semi-auto box before I was wondering what generally happens when they break? Do they just not engage gear or do they slip out of gear when in "D"? I presume the semi-auto would also not work?

How much are they to replace?

Interesting to know in case of future problems (none hopefully!).

Thanks, Chris

[groomi]

CHJ said:

...but never having had a car with a semi-auto box before I was wondering what generally happens when they break? Do they just not engage gear or do they slip out of gear when in "D"?

First signs are usually rattly and jolting gearshifts, then a bit of slipping. This can sort itself out though for a while before ultimately leaving you stranded with no drive in any gear (except in odd cases like mine where neutral provided just enough drive to get onto the pavement and relieve South East Londons rush hour gridlock caused by me).

[robocop]

Further to the discussion about whether or not to use OE Spec oil in a A/T service, I have sought further advice to confirm/deny some of the thoughts above.

The following is from www.testransmissions.co.uk  Ltd based in Westbury who are a large independent transmission specialist:

Thank you for your enquiry. Dexron II/III is absolutley fine for all ZF transmissions. Had the vehicle been here that is was we would have also used. There is a school of thought that would suggest that the manufacturers oil should be used and obviously this can be done so if wished, however the Dexron oil is absolutley fine. As reconditioners we have used this oil on many transmissions over the years with no problems so I am confidnet that all will be well.

Please give us a call if we can be of further assistance.

Best Regards,

Tom Hunt
Works Manager
TES Transmissions
01373 822041


The following reply is from a trade oil stockist www.northwiltslubricants.co.uk  This seems to have been the most comprehensive and full reply I have had so far :

Thanks for your enquiry concerning the use of the correct lubricant for the ZF 5HP24 Auto transmission.
As always, owners will give conflicting advice as to the use of the lubricants in search of an alternative to what the manufacturer stipulates usually based on cost!!.
Having checked the technical manual for this particular box, Jaguar stipulate the Esso LT71141 - Why?
Because during the boxes development stage, jaguar and ZF would have looked at readily available products to do the job (ie Dexron II, Dexron III etc) before they commissioned ESSO to formulate the LT71141. On "sealed for life" gearboxes, the service fill of oil MUST be capable of providing all the necessary operating requirements for both the Flywheel and the Box, Cold and Hot operating conditions etc for the life of that Box ( 100,000 miles). It would be fair to say that ANY ATF Fluid would in part fulfill that requirement but would be very limited ie clutch and stator slip, rapid gear wear would be evident in a short period of time as where the LT71141 is a proven product for 100,000 miles - tried and tested by Jaguar.
It may cost a few pounds more per litre than something like Castrol TQ Dexron III but you would have the peace of mind that you have used the correct product to do the job.


Just to offer some comparisons here are the Technical Specs for the LT71141 and the DIII

Test	Dexron III	LT71141
Kinematic viscosity at 100C	8.1 cst	7.3 cst
Kinematic viscosity at 40C	37 cst	36.8cst
Viscosity Index	204	168

The important factor here is the Viscosity Index which, if too high will cause slip and where a stator/box required a certain amount of friction to operate then this would be a factor.
Also there is a test called the FZG 4ball Wear test, which for the LT71141 is 12 but for the DIII is unknown!!

Hope this offers some assistance

Regards
Barry ( North Wilts Lubricants)

So still conflicting advice, although NWL do put up a more thorough and measured explaination.

Any more thoughts from anyone

[GavinPearson]

robocop said:

GavinPearson said:

No! No! No! No! No!

You DO NOT want to use Dexron III.

Great, looks like I have been given duff gen

Thanks for the advice Gavin, I will get it changed back. Can I still drive the car?.. are you saying long term it will do damage?

Edited by robocop on Monday 4th February 21:49

You can drive the car, but would have the oil changed sooner rather than later. As you know that the internals are relatively clean you could just drain the sump, refill, run, add fluid, block off the weir plug, run for 10 minutes at idle and then drain to try to dilute what is in the converter.
Then drain the sump, refill, top off at the correct temperature and all should be OK.

[GavinPearson]

CHJ said:

I have had my XJR gearbox oil changed as a precaution recently at 80k miles, but never having had a car with a semi-auto box before I was wondering what generally happens when they break? Do they just not engage gear or do they slip out of gear when in "D"? I presume the semi-auto would also not work?

How much are they to replace?

Interesting to know in case of future problems (none hopefully!).

Thanks, Chris

In many cases the first issue seen is that of excessive slip and the transmission selects a gear path that avoids the slipping clutch pack, and it usually comes in with a huge bang.

5HP24s often have the forward clutch go, so as you put the car into D it knows the clutch is slipping (because the sensors are saying so) so the trans engages 5th with a bang.

Interestingly, for diagnosis, if you drive the car to a point where there is a very slight downhill slope you can turn the engine off, resetting the transmission default, then start up in neutral, release the brake to get rolling and the engage D. The engagement will be smooth, and using miniscule throttle you will hear the transmission change up the transmission through all of the gears until you reach 5th. That way you can tell the internal valves work OK, just knowing that the key clutch has failed.

[avos]

@Robocop

First of all I am with GavinPearson, not because I have direct knowledge about the subject; however I have read enough about gearbox oils being part of the design and can understand (a little) the importance. Then as it seems that gearbox oil is one of the most complex oils on the market due to the additional properties it needs to have, compared to f.i. engine oil, I would personally stick to the original specification. I would only consider another type of oil, if that supplier fully warrants the gearbox for damage caused by the oil, and the cost of proof would be paid by the oil supplier.

But to comment on the Viscosities, I have seen different suppliers of Dexron III (with latest specification H) and also different values for the viscosities, and some come closer to the Esso LT 71141 168, like 185-190 (and not the values shown in the table from North Wilts Lubricants).

So as the viscosity at 40 and 100 degrees and the index could be reasonably close (depending on which Dexron III has been used in your car of course, better check it), you might not need to change everything overnight, though I guess it is wise to switch back to the Esso one.

Andre.

[lowdrag]

Thanks lads. I love my Jaguars as well as the next one but for everyday transport I have an old C class Merc so I popped into my local dealer and asked him about the gearbox oil. The car has just passed 90,000 and is due a service and they strongly advised an oil and filter change although MB say it isn't necessary. Seeing the photos above and reading the logic I'm glad to have read this thread.

[P700DEE]

Sorry I also think you should stick to the OE spec oil. To remove all the oil from the gearbox and torque converter is very difficult. Most companies who change the oil . filter etc. do not flush the box nor extract the oil from the torque converter so you will still have old oil present. Mixing oil types is not usually recommended. I had the oil done on my R (Mercedes box) changed last year and I have not regretted it. Note Jaguar say sealed for life, Mercedes say oil change every 60K miles !

[a8hex]

P700DEE said:

Note Jaguar say sealed for life, Mercedes say oil change every 60K miles !

In some cases when Mercedes say for life, they mean life.
(not in most cases obviously, and certainly not with things like fuse boxes... Oh no don't get me started again!)

[NST]

my 2001 xkr has done 65K, what oil does the auto box take? i've been thinking about getting the oil changed along with the diff oil in the summer for preventative maintenance

update: Shell ATF 3403-M 115 is the correct oil for the 5sp merc box used in the xkr.

Edited by NST on Wednesday 6th February 14:08

Edited by NST on Wednesday 6th February 14:09

[Jaguar steve]

Just been on the North Wilts lubricant site.

They stock Esso ATF 71141 in 1 and 5 litre containers - at only £1.50/litre more than Dexron 3. So my previous about only availibility for this oil is in 20 litre drums at nearly £100 is complete bollox..sorry.

Can't see any reason not to use the correct stuff now....

[robocop]

Hi Steve,

Actually it is only available in 20L from Esso, so you are correct. Barry at NWL then decants it into the smaller containers for ease to customers. Most people probably need a couple of bottles of 5L(@ £29.99) to do an oil change.

However, I bought a whole 20L as I am going to do a couple (maybe 3) flushes to get rid of the Dexron. He let me have it for £95(incl VAT) which is a good price, but that is to 'collect' as he is only 5mls away! I negotiated that price for the www.xkec.co.uk club, but I am sure if you mention me he will do the same price for Pistonheads ;-)

Rgds
Simon

...and yes, if I had known I could get it for that price, I would not have had Dexron in the first place!!!!

Edited by robocop on Friday 8th February 18:13

[Jaguar steve]

Thanks for that....looking back through this thread how difficult can a gearbox oil change get FFS!

[robocop]

I know ...crazy!

Although I have decided to go back to Manufacturers recommended OE spec oil, I still find it so odd that so many specialists(like TES Transmissions of Westbury) and independents (Bill Knight, Andover) would recommend DexronIII

To maybe give a final difinitive piece of information on this, I have today, finally received an official reply from ZF GB. Whilst it is no surprise that they advise using the Esso LT71141 oil for the 4.0XK8 5HP24 G'box, I think it is worth reading their reasoning behind it.

Posted here for all to read:

Thank you for your enquiry regarding the correct grade of oil for the ZF 5HP24 automatic transmission as used in the Jaguar application. My reply is based solely on the design and technical requirements of the 5HP24. Cost of the oil is not an influencing factor, as you will appreciate; ZF also has to purchase the oil from Esso.

The design specification of the 5HP24 requires the use of Esso LT 71141 and is filled for life. There is no alternative or equivalent oil, Esso is the only supplier of LT 71141. Under normal operation, the oil is changed after 10 years or 100, 000 mls.

The transmission was not designed to run on Dexron III and if installed you run the risk of premature failure. The transmission is equipped with a sophisticated torque converter lockup control (TCC) system and the correct oil specification is critical to its function and operation. One of the main functions of the oil is to provide the correct coefficient of friction and cooling of the torque converter lockup lining during regulated slip conditions. The longevity of the lockup lining would be adversely affected by the use of Dexron III and in most cases deterioration in shift quality and lockup engagement is also experienced.

I hope these points’ help you make the correct decision to use Esso LT 71141 which will continue protect the longevity of your transmission. The use of alternative oils can only be considered as false economy.

ZF Great Britain Ltd
[e-mail]

I think the bottom line is now that we know we can get LT71141 for a reasonable price, it makes sense to use the OE spec oil.

Here's to the next 100,000mls

Edited by robocop on Monday 11th February 18:21

Edited by robocop on Monday 11th February 18:35

[NormanD]

PART 2

Oil change in the XKR in this months (March) magazine.


They will be doing an article on the 6 speed later in the year