Hello,

Been a while since I've checked in here. My wife's S-type has been gone for over a year now, but I have a problem with a current zf trans and every other google search I do sends me here.

09 Kia Borrego 4.6L, about 145k. Bought it with 133. Drained 3-4 qts of fluid within the first couple K and refilled with SP. Old fluid looked worn, but nothing out of the ordinary. Haven't had the pan/filter off yet.

Overall, it runs and drives perfectly fine, and most drivers wouldn't even notice, but a couple things...

The one that bothers me the most is when it is in 6th and you let off the throttle there is a mild whine, kind of like a worn out bearing. Also, when it gets to 59-60 and downshifts to 5th there is a noticeable clunk.

1st is almost pointless. It shifts into 2nd immediately after it moves from a stop. Maybe this is normal, but it seems strange to me.

If I drive it in manual mode it feels better overall, but there's still the whine when coasting on the highway.

Should I just get it to the trans shop and let them poke around?
There's an ATSI in town that I have quite a bit of faith in.

 

Keep in mind that the ZF 6HP26 fluid capacity is 10 litres. Your one drain-and-fill replaced less than half of the original ATF. Before taking the vehicle into the shop and paying someone else for their time, I would do at least one more drain-and-fill using Mercon SP so that most of the ATF in the system would then be relatively fresh. I would then drive the vehicle for a week or so to see if the ZF begins to operate more smoothly again....

At 145,000 miles it may indeed need a refurbishment, but I would try more fresh Mercon SP before considering that option. At less than $7 per quart, it is certainly worth your time and effort if you are doing the drain-and-fill yourself....

 

Yeah, I knew it wasn't much, but we bought it with 133k and I didn't see any entries in the maintenance records for trans service (one owner, always dealer service). We were planning for a ~500 mi trip soon after the purchase so I wanted to do SOMETHING. I'll probably get under there again this spring. I need to do the pan too.

 

Hi n2audio,

A few thoughts: 1st gear is also used very briefly in Jaguars that use the 6HP26, unless in Sport Mode and under hard accelleration. Jags are tuned for low Noise, Vibration and Harshness (NVH), and 2nd gear is perfectly adequate for moderate accelleration from a stop. This is probably also how your Borrego is tuned. If you were to start up a steep hill, it's likely that it would remain in 1st longer.

The whine you describe when you let off the throttle could be indicative of low transmission fluid, or it could indicate failing pinion bearings in a differential (rear, or front if your Borrego is AWD).

The harsh downshift from 6th to 5th may improve with a full fluid flush (the cooler lines are convenient access points). With the Jaguar implementation, it is also possible to clear the adaptations in the Mechatronic (combined transmission control module and valve body), and upgrade the firmware to improve shift quality. A KIA dealership may be able to do something similar with your Borrego.

Aside from flushing the fluid, another thing you can check is the large electrical connector on the rear of the transmission. The plastic sealing ring tends to develop leaks and allow transmission fluid to contaminate the connector pins.

I am attaching some of the Jaguar TSBs in case they may give you any clues. You might see if you can find any relevan KIA TSBs.

Cheers,

Don

 

A few more hours were spent on this one. From abonano's comments about the E-clutch, I devise a simple experiment. I put the car in 3 on the J-Gate. According to some literature, I read the E clutch is not specific to a gear but rather messes with the ratio in gears 4/5/6 like an overdrive. If I keep the car in 3 and drive around it's smooth as silk, not hunting or bouncing around. If I go into 4 or 5 the fun starts. So suspecting it's related to the E-clutch after all. I have read it's a smaller clutch and typically the first to burn out.

I do have a question though. The previous owner had put Valvoline MaxxLife ATF fluid in it. As I mentioned it was shifting hard when I got it. I had it drained and put ZF fluid in it, that's when the hunting started, it was drained a second time and more fresh ZF6 was added (so the MaxxLife should be getting pretty diluted by now). The car is better than before so I am wondering if there could be an issue with the MaxxLife in that transmission. Maybe the E-Clutch being the smallest is the first to slip.

Anyway at the wild shot point in the debug now. Has anyone ever tried Lucas transmission slip oil in these or is that a no-no?

Thanks again for all the input. If I can't fix it hopefully someone will get some benefit out of this thread anyway.

John.

 

ZF lifeguard 6 (or a very select few other ATFs) are the correct ones for 6hp26. See:
https://www.jaguarforums.com/forum/s...s-type-264102/

 

I always find it interesting that people ignore what the engineers who designed a complex part of a vehicle, such as a gearbox, recommend for fluid specifications simply to save money. The best part is when the modification they attempt causes the assembly/gearbox to not perform correctly, and want a solution that's in itself inexpensive.

I know there are forum members who have successfully used other fluids in the ZF 6HP26/28, but those fluids meet the specification for Ford, Stellantis or other manufacturer using a variant of the 6HP26/28.

While this may not be the situation in this instance, why substitute another gearbox fluid for what the manufacturer's specification recommends?

It's good that you're using Lifeguard fluid to flush the gearbox to see if performance can be restored.

 

Hi John,

To save you from having to read through a lot of incorrect information, the only three fluids we know are correct in the ZF 6HP26 are ZF Lifeguard 6, Ford Motorcraft Mercon SP, and Shell Spirax S4 ATF MSP. All three fluids are manufactured by Shell and are chemically identical aside from dye color (with normal batch variations, of course). This fluid is bottled under various automaker brands (Jaguar, Land Rover, BMW, Maserati, Hyundai, Audi, VW, Aston Martin, Rolls Royce, Ford, Kia, Bentley, etc.), but it is all made by Shell.

You would do well to flush all of the Valvoline MaxLife ATF out of the system. It's viscosity is significantly higher than that of the correct fluids (it's too "thick"), and the 6HP26 requires a "thin" fluid due to the close tolerances and small passages that made it possible to fit six forward gears into the same space where only five gears used to fit.

There are multiple ways of exchanging the fluid. One method is described in the post at the link below. I prefer this method over disconnecting the cooler lines at the radiator due to the risk of damaging the radiator or causing leaks that are difficult to resolve, either at the fittings or crimp joints or in the flexible sections of the cooler lines:

ZF 6HP26 /28 Transmission Fluid Flush DIY

At the very least, one more drain and fill might be worth the time and fluid. I don't know your location, but in the U.S., Motorcraft Mercon SP is the most available and affordable option and is available at Ford dealerships and stores like Advance Auto Parts. Since Mercon SP is chemically the same as LG6, aside from its red dye, it can be mixed with LG6 with no problem.

Remember that the fluid level must be set with the vehicle level and the transmission fluid (not the plastic pan) at a temperature of 40°C / 104°F. The easiest method of measuring the fluid temp is with a scan tool that can view Live Data. If you use an infrared thermometer, be sure to aim it at the fluid dripping from the fill hole and not at the plastic pan, which can have a temperature several degrees cooler than the fluid. If the fluid temp rises much over 40°C / 104°F, the fluid level will be too low.

I have used Lucas Transmission Fix in older transmissions, sometimes with noticeable improvement, sometimes with none. But a friend who is a retired transmission rebuilder has told me more than once that the Lucas Transmission Fix causes more problems than it solves in transmissions that already have internal component failure, causing more components to require replacement than might otherwise have been necessary. I personally would not put it in an advanced modern transmission like the 6HP26.

EDIT: One other thought - I don't remember the model year of your Jaguar, but in 2005 Jaguar issued a firmware update for the 6HP26 that helped resolve various harsh shift issues. If your car is a model year '04 or '05, it might benifit from this update. It has helped several cars I service, some whose owners were convinced their transmissions needed to be rebuilt.

EDIT: See the attached ZF documents which give the full instructions for setting the fluid level. I couldn't get them to attach last night but apparently the forum glitch worked itself out and the documents came through eventually.

Cheers,

Don

 

Always good advise from Don. I would like to add something, which Don was probably thinking of, but not writing...:
Don Wrote: "Remember that the fluid level must be set with the vehicle level and the transmission fluid (not the plastic pan) at a temperature of 40°C / 104°F."
Addition: ...; while the engine is running!

 

Thanks, Peter,

I actually intended to attach the instructions for setting the fluid level but for some reason the forum wouldn't allow me to post the attachment last night. There's actually more to the fluid fill procedure than just fluid temp and having the engine running.

Attached is a ZF document which gives the full procedure for setting the fluid level. In addition to having the vehicle level, the engine running, A/C and other loads off, and the fluid temperature correct, you also need to run the gear selector lever through the prescribed gear positions, holding each position for the minimum time prescribed, etc. Just follow the flow chart.

Cheers,

Don

EDIT: Hah! I see now that a couple of documents I tried to attach last night actually did get posted eventually with my previous post. Go figure.

 

Interesting documents. I bet most people would not know about the extra gear selector procedures. So, good to know,
There is even the tightening sequence of the oil-pan-bolts and the torque depending on the material of the pan.

Criticism on the ZF document: It describes a 50%-ATF-fluid change only, not a full flush, which in my opinion does not serve any purpose in any situation. It is like doing an engine oil change, where you refill 50% of the old oil after releasing it, and top it up with 50% of new engine oil.

The ZF document also does not mention that STEP 1 is to loosen (not remove) the oil filler plug, which frequently is recommended by various people here on the forum. The logic is simple: It is very hard to open it, Thus, if someone does a ATF fluid change (release of old ATF first) and then finds, that he cannot open that filler plug, he is in a real pickle, because he cannot DRIVE it to the garage anymore, plus towing without ATF also is not an option, as the ZF document states... A tilt-tray-tow-truck to the garage might then be the only option...

 

Hi Peter,

Since withersjw has already had two drains and fills, and has enough Lifeguard 6 for one more drain and fill, the ZF document I posted should be a good reference for him.

The tip to loosen the fill plug first is very important, but ZF probably omits it from their document because it is written for professional technicians who already know the basics of transmission service (there are plenty of other important tips that are common knowledge among pros, so they aren't repeated in every service document). But many members of these forums and others have learned the hard way that draining the fluid first, then being unable to open the fill plug, creates a serious challenge. If his happens, the best course is to measure the old fluid drained. Put the same volume of new fluid, plus a little extra for spillage, into a fluid pump. Inject the fluid into the transmission via the drain hole and quickly reinstall the drain plug. Then figure out how to loosen the fill plug!

Cheers,

Don

 

@ Don: Filling by the drain plug sounds messy. But inspired by your idea:
If you are in that pickle, maybe take that amount of fluid as described by you, remove the upper pipe (coming from the transmission), which goes into the radiator, and fill that fluid into the radiator opening (via funnel and hose). That should work.

 

That will work, but I don't like disconnecting the cooler lines from the radiator unless I absolutely have to. Too many reports of damaged radiators and cooler line leaks after being disturbed.

Filling via the drain plug port is standard procedure on lots of Mercedes-Benz, Aisin and other transmissions, so there's nothing unusual about this method - just a little spillage while you get the drain plug started back in.

Cheers,

Don

 

@ Don: Yes, I read that in one of your threads before that your do not like disturbing the pipes on the radiator...
Nevertheless, I would have another question in these regards - maybe you know the answer - but it is about X-Type, thus, I just created a new thread with my question in the X-Type section:
https://www.jaguarforums.com/forum/x...x-type-266112/