Ok, time for another newb question: Again, 2004 XJ8, ~71K miles. A few days after I bought it, I had it at the local dealer to to an OBD-II readout to see if any faults were in the computer, and if any readings were getting close. Nothing showed up, but there was a pending recall for an ECM software upgrade, which the dealer provided. In addition, they reset the "learning" mode of the transmission, to adjust to my driving habits vice the previous owners. Nice, I thought.

Now, there are occasions, admittedly rare, where I can be sitting stopped at an intersection and when I press the accelerator, the transmission seems to "bang" into gear. Has anyone else experienced this? It's not all the time, I haven't particularly noticed if it happens when the car is still "cool" (It's June in South Texas, cool is relative), etc. The first few I wrote off to the learning period, but now I'm not so sure.

Appreciate any insight. I am totally loving driving this car. My wife, who loves her 2003 Chevy Tahoe, even wants to drive it, and she hates riding so low to the ground.

Mitch

 

Hi Mitch, I bought my '04 last September and have seen times when after a stop sign it seems the car slid into gear abruptly on take off. Now I don't always come to an absolute and standing stop, so I have written it off to the car learning my driving style as opposed to the PO.

 

So, it never did this before they reset the learning curve?
Nice folks.
It would have learned your habits and modified it slowly.

Now, it's going to have to learn from scratch.
The problem with that is, if you take off hard, it will learn that, and you'll be harsh shifting from now on.

I remember some General Misunderstandings, where when the computer was reset, that happened, and the "kid" picked the car up from the shop for the "folks", and they brought it back the next day with a "transmission problem", because the "kid" had done burnouts at every stoplight on the way home, and "taught" the empty computer to shift that way.

 

I am fairly certain it didn't do this before the reset, but I bought it on a Saturday, and the reset was done the following Thursday, and I can't recall if it was happening before.

I consider myself somewhat conservative in driving. I'm 46, and I think I've got all those burnouts and jackrabbit starts out of my system. If I do accelerate heavier than normal, I don't "tromp" the pedal, but try to press the pedal gradually down.

Anyway, it sounds like it's something that will eventually resolve, as the computer learns my driving habits. It was just unnerving enough to be a concern, but not happening often enough to go to the service shop and pay $120/hr :^/

Thanks everyone. This forum has been a great help in the short time I've been here. Hopefully, my learning curve will taper off soon so I can start being a help, as well.

Cheers!

 

I have hard shifts from time to time. Once a week or so.
Oddly enought all ahrd shifs stopped when they reset the TCM as part of the ECU recall.

A couple of days later hard shifts are back. I'm also a cautious driver. Sometimes I wonder if that's the reason and I should "push" it more.

Or could be old transmission fluid.

 

I was having a similar problem and took it into the dealer just before the warranty was out. They did the TSB on the transmission noise and it has been as smooth as glass ever since. They put in a transmission additive.

 

As an 8-month owner of a 2004 XJ, I am having this issue as well. The dealer gave me the same "reset and re-learn" schpiel that you got. And I have the same issue still.

I am VERY interested to hear what the additive was done for you!! and what was the TSB that they used to do it?..

Thanks.

 

Hi, I had this on my Uk 2003 3.5 V8 as well, the dealer did a reset and it did not make much difference. I then had them do another full reset, mind you it did cost about £100, after that I drove it without harsh acceleration and did not use sport mode for about 1000 miles or so, it has been fine now for about 4000 miles, so I think that is sorted now.
hope this helps, regards form the UK

 

The bulletin #JTB00040 was used to install the additive. If your car is out of warranty, you will have to foot the bill, about $250.

 

Well, I suppose I was just impatient (and a bit apprehensive). It seems to have stopped, at least for now.

Thanks, all for the suggestions!

Mitch

 

Well, as a follow-up, yesterday (Sunday) evening I got the amber warning light and "transmission fault" message on the display. Since we were about a block from our destination, I just parked the car, we had dinner, then when we left, the car seemed to work fine. Just the heat, I assumed (it was over 105 degrees at the time). No fluid leaks on the ground, or smell of burning TF.

Today, I drove to work (22 mile commute one way) with the radio off and the fan down to listen. No problems noted. On the last few miles of the drive home, I stopped at a 4-way. When I started off, the light and fault message returned.

I spent my spare time at work today searching forums for information, and just got off the phone with the local Jag dealer to bring the car in for repair. I bought an extended warranty (not from Jaguar), something I normally never do, so I think it might only end up costing $200, but my fear now is that the warranty company will not honor replacement of the transmission, but insist on repair or rebuild.

Oh, well.

 

I know we seem to have been over this quite a lot in this thread, but there are still a couple of things that I don't get.

Ok, here is what I read:
1) The tranny in my '04 XJ is a ZF 6HP26.

2) The OEM fluid for the tranny is a Jag dealer item, generically Shell M1375.4.

3) There is a TSB for hard shifts, #JTB00040, that drops in an additive to the existing tranny fluid. However, this can ONLY be done ONCE (per the TSB).

4) Castol claims (and is the only manufacturer that I can find) that its Import Multi-Vehicle ATF IS an appropriate replacement for the Shell M1375.4 fluid (per http://www.castrol.com/liveassets/bp...s_ImportMV.pdf)

6) The concensus appears to be that you should only use the Jag fluid, regardless of the exhorbitant cost.

7) Even though this transmission is used in several other vehicles, the concensus is that the tranny programming will not respond favorably to a change in the viscosity of the fluid and may have disasterous effects.

SO..... here is the $64 question...

If the tranny is going to "respond poorly", to whatever extent that is, to something other than the OEM fluid,.... how does it respond to the OEM fluid with an additive "NOT poorly"?

I mean, I don't know exactly what the additive does, but I would have to assume it would change the viscosity to some extent. And if the original fluid with an additive is OK,.. then why not another brand (at one twentieth the price, no less).

Lastly, the real thing that I wanted to do is to change the ATF filter. Get out any metal particles and gunk that is in there. But I believe to do that, you have to drop the pan. And if you are going to do that, you have to replace the ATF. So,.. that's where I am.

Welcoming thoughts on this one.

 

1. Correct. Except XJR use slightly modified version also used in AMG Mercs.
2. Fluid is formulated by ZF, various OEMs sell it under different names.
4. Castrol e-mailed me, saying "Well it's kind of comaptible, but viscosity is different and I can get lower mileage". I can forward you the e-mail if you want.
6. ZF says the fluid name is LifeFuardFluid6 - you can get it from BMW, Benz, Bentley, Audi and various ZF dealers - make sure you get the fluid for 6HP26 equipped vehicle. Hyundai Genesis with 4.6 engine also uses the same transmission, may be they'll have the fluid cheaper - have not checked.

The additive is also formulated by ZF - I assume they built the trany and know what they are doing.

I had a gasket seal replaced on my trany, they saved the old fluid and ony added 1 quart.

 

Just wanted to follow-up with the fix action performed by Jaguar. Essentially, they reprogrammed (reflashed?) the TCM and reset the learning mode. That's it. It's been 5 days since, and everything appears to be working. The days have been in the 100s, so the heat hasn't been affecting it. The day after the repair, we drove ~180 miles to Corpus Christi and back with no problems. Here's hoping that the issue is resolved.

Thanks to everyone for their input.