I've been researching previous threads about the not uncommon surging problem, but I can't piece together from them exactly what I need to do for mine. I have an '04 VDP with about 176k miles now. Fairly soon after I changed the transmission pan/filter, I started getting a 100-200 rpm surge. It's more persistent when the engine is cold and under a little load. When cruising without engine strain the surging is gone or barely perceptible. After 20-25 miles of driving it's much, much less.


I had a very good local transmission shop give me a diagnosis. They put a scanner on and let me go along for a test drive. I had driven about 70 miles before arriving there, and unfortunately it wouldn't do its surging thing on the test drive. So they said they didn't find anything wrong with it, but recognized it could be the torque converter and recommended waiting until there were more symptoms before bringing it back for another check.


My questions. What's the likely cause? Will it hurt the trans to keep driving this way? Some drivers have said they just live with it. I can get a reman torque converter from Precision in Iowa for $262 (plus $200 refundable core charge), which is the best I've found. The trans shop said that's actually where they get theirs. The labor would probably be about 8 hours, although I didn't get an estimate. So I'm looking at around $1,000 for the TC job. Any thoughts? Thanks!

 

Hi kbeachy,

One thought that occurs to me is that perhaps your transmission doesn't like the new fluid or the fluid level. Any possibility that could be an issue?

Cheers,

Don

 

I have re-checked the level, and it appears okay. I think I would have shifting issues if it weren't, and it shifts extremely smoothly. In fact, the fluid change got rid of a hard/lurch sort of startup when stopped and then accelerating.
I used Mobil 1 ATF and some Lucas additive. I had researched that the Mobil 1 would work. Maybe it's something with the type of fluid?

 

It very well could have something to do with the type of fluid. If you have the ZF 6HP26 gearbox, the fluid ZF specifies is Lifeguard 6.

According to the Mobil 1 ATF datasheet, its viscosity at 40ᵒC is 36.3 mm2/s:

Mobil 1™ Synthetic ATF


The viscosity of Lifeguard 6 at 40ᵒC is 28 mm2/s (a very low viscosity compared to many ATFs):

http://www.zf.com/media/media/docume...enblatt_EN.pdf


I could not find a viscosity rating for Lifeguard 6 at 100ᵒC, but that specification for Mobil 1 ATF is 7.4 mm2/s. For comparison, Redline D6 ATF has viscosities of 30.7 mm2/s at 40ᵒC and 6.4 mm2/s at 100ᵒC.

Viscosity is just one of the important specifications for a transmission fluid, but it seems possible that the viscosity of Mobil 1 ATF may be too high for the ZF 6HP26 transmission.

Since the ZF 6-speed gearboxes were used in a lot of high-end vehicles, there is a vast amount of information and speculation about Lifeguard 6 on a wide variety of forums. Here is just one example:

http://forums.vwvortex.com/showthrea...ion-Fluid-type

A statement in one post in that thread may be relevant to your symptoms:

"According to VAG, an important attribute of the Lifeguard 6 is the friction coefficient characteristics required for the TC regulator (lockup clutch is designed to slip while driving instead of just closed or open). Without these modifiers, it can slip too much, or grab and shudder or just make a moaning noise........"

Sure makes me wonder if the Mobil 1 ATF may not be a suitable fluid in our Jags...

Cheers,

Don

 

Wow--that's very helpful. So if indeed I need to mortgage my house in order to buy some ZF fluid, what would be the best way to counteract the Mobil 1 and Lucas additive that I put in there? Do repeated changes?

 

Probably - since the torque converter typically holds 4-5 quarts that don't drain when you open the drain plug or drop the pan. It might be worth searching the forum for information from members who have had recent transmission service or upgrades on their X350s or X358s. I think JimC64 had some work done on his transmission, and he posted photos of a really outstanding transmission service shop in the U.K. There may be some info in Jim's posts related to professionally flushing the fluid in a transmission.

Please keep us informed!

Cheers,

Don

 

Are you positive the surge was not there prior to the service? I'm at about 160k miles now and I get a surge as you describe, and always have. Goes away once up to operating temp, so I just ignore.


Bob
Liberty MO

 

It absolutely started AFTER the pan/filter change. Probably within 50 miles after.

 

This surging issue has to be the "hardiest perennial" on the X350 forum. (S-types are also affected.).

I am told it is cured by swapping out the torque converter. However, the surging disappears when the transmission fluid has warmed up, so how can it be a defective torque converter ? If I was told I needed to spend hundreds of pounds to cure it, I'd want to know why the surging occurs in the first place.

I think somebody in Jaguar engineering needs to come on here and explain it. As my car is 11 years old, eleven years is surely enough time for the cause to have been determined and announced.

 

The S-Types affected only seem to be ZF 6HP26 trans and certain years. Most haven't even checked the fluid level let alone changed it, never mind any other trans maintenance/repairs so I guess we really have terrible data...

If it's the TC lock-up not occurring at some temps then you'd think fluid/repair/software should fix it. No idea if anyone's even talked to jag corporate. (Dealers are franchises and a fair few are hopeless, to be nice.)

If it's the same issue with same trans with XJ then it would be good to get ZF / Jaguar comments.

 

My Jag had the TC replaced under the extended warranty for surging. It does not surge, so it solved the problem.

I'm about to change the fluid/filter with lifeguard 6. CTSC seemed the best price overall.

Seems to be an era of ZF trannys with this issue, common in the 5 speed ZF's in Audi's of the similar years.

 

I think what I'm going to do is have my local trans shop flush the trans fluid for me and refill with Lifeguard 6. They'll charge about an hour and a half labor. I found the best price for the Lifeguard 6 on EBay, which ends up being less than CTSC charges once shipping is figured in. I did about $23/quart including shipping charges.
This is less expensive than replacing the TC, and I'll be sure it's not the fluid that way. It just seems odd that the problem started right after I replaced the fluid with a too high viscosity mixture.

 

RCSnyder,
I'd be interested in hearing more about your surging. When did it start? Already doing it when you got it? At how many miles did it start? What do you mean by operating temperature? How many RPMs will it surge, and under what driving conditions? Has it gotten any worse over time? All your answers will be much appreciated!


rosskuhns,
I think I remember your mentioning the TC change when we met. What mileage was that at? Anything more you know about its occurrence?


Thanks, guys.

 

I just looked up the invoice. It was at ~43k miles by the Jag dealer.

I recall the PO, a meticulous member here, told me he rode with the tech, who agreed the car was surging.

I see from the invoice notes that "IDS INSTALL SOFTWARE & STILL THERE REPLACE TRANS TORQUE CONVERTER AND FILL TO SPECS".

So they did try a software update but it didn't do it.

The PO and I had both thought they would have changed the fluid too, but I noticed that it was only 1 AUTO TRANS - OIL part number.
oh wait, I just looked the part # up, that is a 5 liter jug! I feel better

I'm still going to do the fluid and filter, my shifts are a bit harsh. If that doesn't take care of it, the calibration has drifted and I'll get a dealer to reset.

 

Ross -


Let us know how it goes. You'll probably have the newer pan bolts, and they'll probably come off pretty well which will be nice. I hope that takes care of your harsh shifting, which I expect it will.

 

I was at my local Jaguar independent yesterday to have four tyres fitted. We got into conversation, as you do, and I said the only problem I've never been able to bottom is the "hunting" gearbox during warm-up. The technician used to work at Jaguar, and told me that to speed-up warm up of transmission fluid, there is code in the TCM software to rapidly switch the torque converter lock-up on and off to generate heat. The problem with this clever wheeze was that the friction surfaces in the TC were not suitably profiled for this action, so owners see the 100-200 rpm hunting. A mod was done to later torque converter production that re-profiled the friction surfaces.

Because the syndrome disappeared after a few miles, I had always thought this was a TCM software problem, so suggested the simple answer would be to alter the TCM code to not carry out this rapid switching and asked why Jaguar had not done so. The answer is because it is there for emissions purposes, (quicker warm-up, less emissions), the program cannot be altered as it would affect the emission rating of the car. Of course, one can always fit a new torque converter to cure the problem, but it is not really a problem, it is a feature !

The reassuring news from all this is that anybody worrying that the gearbox or torque converter is about to pack up can rest easy. Just learn to live with the hunting. I just put the transmission into '4' until I've done a few miles.

 

I bought my XJR about 4 years ago with 78k on the clock. Turned over 160k yesterday.


Surge occurs - and has as long as I've owned it - under light throttle, at low speed (<30 mph) and on the slightest of grades until the temp needle moved up past the 1/4 mark (Full warm is just below half-way). The surge consists of a 2-300 rpm up/down under these conditions. It is clearly caused by the converter not locking under those conditions, as it does when it's warmer.


Oh, and when it's really cold, it actually surges less. Say, below 10 F as it was much of the past two winters here. But at those low ambient temps, it also seems to run a different shift map, holding the lower gears longer. So, what, when warmer, is a 4th gear surge condition, in the extreme cold, I'm still in 3rd.


And, yes, my car sits outside all year and the first 2 miles in any direction is in a 30 mph zone. I do get the surge and other than occasionally dropping the J-gate into 2nd, I happily live with it.


It is possible that the surge was not "original" and the previous owner traded the car because of a dealer's torque converter diagnosis, running scared from a potentially expensive repair.


I have not yet serviced the transmission, and know I need to get this done, but other than the occasional hard 1-2 shift, it is flawless.


Overall, this car has been the best car I've ever owned. Not only does it get me from A to B reliably and comfortably, but it truly has been a quality piece.


Hope this makes sense.


Bob
Liberty MO

 

Hi kbeachy,

I was thinking about your surge issues and the sequence of events. I'm wondering if, when you changed the transmission pan/filter, did you simply refill with Mobil 1 ATF, or did you do two or three fluid changes to help flush the old fluid out of the TC?

If you just refilled the one time, then your fluid is a mixture of the Mobil 1 and the original Lifeguard 6. I have read a lot of accounts online of owners who have experienced bad fluid interactions when draining and refilling the trans fluid only once. I wonder if, either rather than, or in addition to the Mobil 1 viscosity being incorrect, a bad interaction between the Mobil 1 and Lifeguard 6 is the cause of your TC acting up and the resulting surging?

Cheers,

Don

 

Thanks for sharing your experience Fraser-I have this slight surging under the exact conditions which kbeachy describes ie

"under light throttle, at low speed (<30 mph) and on the slightest of grades"

This only occurs for about 150 yards in one spot.

I can stop being irritated and worrying about it now!

 

Thanks for you help, Don. I did only add the Mobil 1 once, so it is mixed with the original fluid along with the Lucas additive.


I have an appointment for this Thursday to have the ATF flushed and new Lifeguard 6 put in. I invested in 12 liters of the stuff so as to be sure to have enough for the infusion. It will be interesting to see if that makes any difference. One way or the other, it will be known whether the fluid is the cause of the surging in my particular case.