Being a mechanical neanderthal, i am totally nonplussed at the turn of events this past week. My usually realible 3.0 S-type 2003 with 60,000 miles has finally given me a dreaded warning light..."gearbox fault". I think the car started to run in limp mode using gears 3 and higher. There was no engine warning light. So like an idiot i head off to Aamco to take advantage of their "free" diagnostic and after 4 hrs they tell me they couldn't get a read and it would cost between $200/400 to read the codes. They did say i had a transmission fluid leak which they topped up. I get out of there as fast as i could and drive to a local highly regard jag mechanic. We got the codes P1784/P1785 (transmission mechanical failure) and he's saying i need a new tranny. Jag want $4500 for 1 yr warranty, Jasper offer 3 yrs for gulp over $6 grand and i found one at europeantransmissions for $3200. As i drive out i notice immediately the fault light has gone and car seems to be driving normally. What the heck is going on here?? Called up the mechanic and he's still relying on that code reading. Should i be taking this somewhere else to find the leak or is that wasting time and $$$. Another shop is saying talk to Jag customer relations in Mahwah...silent recall blah blah huge problems historically with these transmissions. I always thought that the zf's were hugely reliable.

 

how the hell did they top off your tranny fluid?

Oh, and get a new battery.

 

I'd like to know as well...and with what and how much was added?????

The electrical sleeve is notorious for causing a leak, plenty of threads about that.

Here is one if you would like to educate yourself about it:
https://www.jaguarforums.com/forum/s...ics-faq-30991/

Plenty of others about the ZF6HP26 in the FAQ

 

You cannot just casually top up the fluid in a 6HP26 box. I agree with replacing the battery first it's your cheapest option. After you have changed the battery drive the car and if you get a "Gearbox Fault" have someone pull the code immediately.

The ZF box is considered very reliable with the notable exception of the connector sleeve. Also a TSB was issued for the 03 concerning the faulty lining in the torque converter it will throw a P0741 code. My STR is in the transmission shop getting the torque converter rebuilt. I spoke to the techs yesterday and the rebuilder said the lining was indeed shredding.

It took me some time to find someone I felt confident knew this box and it can be worked on. If you drop the pan for any reason get the sleeve connector replaced and fluid changed. You can use the Land Rover fluid for their 6HP26 box it's Lifeguard6 at a fraction of the cost and readily available at any LR dealer.

You may solve your problem with replacing the battery but be aware of the concerns I have noted.

This advice is worth exactly what ya paid for it...

 

I wouldn't believe ANY transmission shop that casually told me, "Oh, we topped up your ATF in your S-Type." I would be asking for step-by-step details on how they supposedly did so. It would become very obvious very quickly that they are simply lying....

And I concur with a new battery as your first step if your existing battery is older than 4 or 5 years....

 

mistral - welcome to the forum (and please post an into in the New Member area).

If they did actually do any work on the gearbox it may well now be underfilled or overfilled. Both are bad news. Any way you can check if they actually did mess with it? (The fill is under the vehicle.)

I'm struggling to find those codes (meanings or even their possible flagging) for your car

 

I did a search for those 2 codes and came empty through alldatadiy.

 

SeaRanch, how did you determine that the torque converte required a rebuild?

OP ran into a typical trans. repair shop lookin for a sucka.

 

TSB and repeated P0741 when transmission hot, climbing hills and slipping down a gear from 6 to 5, 5 to 4 and later manually shifting into say 4 when climbing a hill and backing off the throttle slightly - bingo another P0741. In normal driving the box worked perfectly but the slipping was getting worse while I sought out someone competent to repair it.

In Canada an OEM torque converter is $2,000 and $1,426 from Nalley. The Tech working on the box suggested a rebuild and in fact even Brutal suggested a rebuild when he responded to another owner with the same problem.

My STR is my summer - have fun car. Since I had the sleeve connector replaced it was shortly thereafter this issue raised it's ugly head. I subsequently checked the fluid level myself and found it to be overfilled by 2/3 of a litre. Drained out the excess and the problem went away for 5 days and then came back.

Been dealing with this for almost two months. No long road trips and summer is almost gone.

 

I think you're right. Let's hope they did no actual damage.

I think they made up the codes!!

hmm, unless they were P0784/P0785. (Covered by TSB JTB00072. Reflashes the TCM. Dealer-only, or a good jag indy.)

 

OK, first off thanks so much for all your input. There seems to be some confusion about the "seeled" zf. So i called up Jag service and they told me its only "semi sealed" and can be topped up. My mechanic confirmed this. The codes P1784/5 are Jag Diagnostic Trouble Codes (also confirmed by jag service) indicating transmission mechanical failure. So apparently certain problems can snowball and throw out additional codes really confusing things, ie gearbox fault. I've been advised to drive normally and if the gearbox fault comes on again get it prompto to a code reader...easier said than done. The advise about locating the leak is most helpful. Of course it would be terrific news not to have to replace the whole tranny.

 

I don't think that there is any confusion, at least not from the people who responded as they are well aware of the filling procedure.
ZF and Jaguar state that the box is sealed for life, this is not true and the fluid can be drained, re-filled or topped up, however it is vital to follow the correct procedure which involves monitoring the gearbox temperature and checking the level within a fairly narrow temp range. Hopefully this procedure was followed.

 

+1

The details are in the FAQs

Something's wrong, though. No-one has ever heard of those codes before, despite having access to jag technical documents, workshop manuals, etc.

I found the codes for Fords, but the S-Type is not a Ford and does not use the same control modules in this regard.

 

my 97 xk8 was running pretty good until one day i started it up and it gave me a gearbox fault code. so i just let it pretty much sit in the garage with a cover on it. then i replaced the rotary switch it cost me 100 bucks or so, tried to start it and the battery was dead. I took it to autozone to have it charged and checked, autozone told me that it was a nogood battery. I went to o,reilly to second that emotion and they said it was a good battery. Now the xk8 says that the battery is not charging and im getting gearbox fault and stability control failure along with a abs light. Im thinking changing the battery and going from there.

 

Can't speak for the XK8 (wrong forum LOL) but for the S-Type it's tough to test a battery properly - the old-fashioned way simply doesn't pick up a failing battery whereas the computer modules will!! Gearbox fault is often just failing battery - and it'll likely test "OK" even though it isn't.

 

The mechanic has access to same online service codes and manuals as jag service. He pulled up same codes which i also found on this website....
Jaguar Check Engine Light DTC Trouble Codes
P1784 Transmission Mechanical Failure - First And Reverse
P1785 Transmission Mechanical Failure - First And Second

 

Those codes are not S-Type specific...

Regardless, did you change your batt yet? And did you ask you Mech how he Topped up your tranny? Details please.

 

Sadly many of those are WRONG.

They also are not specific to the S-Type let alone your car's model year. Ignore them. Use proper Jag ones.

+1 on the tranny fill. You are in danger of writing-off your tranny at the moment. I am (sadly) NOT joking.

 

We are not trying to poke you in the eye here. Just trying to help. It is very possible that you have serious tranny issues. But it is also very possible that your Mech either does not know what he is talking about, miss-informed, or just plain trying to rip you off. It is also possible, and VERY LIKELY that all your issues may simply just be a bad Battery. The leak still needs to be addressed.

But please, get detailed information from your Mech on how he topped up the fluid. This will let you, and us know if he does know what he is doing, or ripping you off. Like has been said, it is not an easy job, and takes time, and is a temp sensitive procedure to be done. Plus it is not in an easy to get-to location.

Then, go get a battery. Even if it's not the issue, your batt is old and these cars HATE bad batteries.

 

What he said. GO GET A GOD*MN NEW BATTERY.

Jaysus...